1 SPF-001 (Rev.D1) DOCUMENT RELEASE AND CHANGE FORM Prepared For the U.S. Department of Energy, Assistant Secretary for Environmental Management By Washington River Protection Solutions, LLC., PO Box 850, Richland, WA 99352 Contractor For U.S. Department of Energy, Office of River Protection, under Contract DE-AC27-08RV14800 TRADEMARK DISCLAIMER: Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof or its contractors or subcontractors. Printed in the United States of America. Release Stamp 1. Doc No: HNF-14755 Rev. 06E 2. Title: 242-A EVAPORATOR DOCUMENTED SAFETY ANALYSIS 3. Project Number: ☒ N/A 4. Design Verification Required: ☐ Yes ☒ No 5. USQ Number: See Block 8 ☐ N/A 6. PrHA Number Rev. ☒ N/A Clearance Review Restriction Type: public 7. Approvals Title Name Signature Date Clearance Review Curry, Mary P Curry, Mary P 06/27/2018 Design Authority Goetz, Tom Goetz, Tom 06/25/2018 Checker Lansing, Lisa C Lansing, Lisa C 06/25/2018 Document Control Approval Porter, Mary Porter, Mary 06/27/2018 Originator Smith, Ryan D Smith, Ryan D 06/25/2018 Responsible Engineering Manager Goetz, Tom Goetz, Tom 06/26/2018 USQ Evaluator Smith, Ryan D Smith, Ryan D 06/26/2018 8. Description of Change and Justification Incorporates DSA page changes from negative USQDs (EV-15-0448-D R1, EV-17-0089-D R4, EV-17-0504-D R1, EV-17-0723-D R0, EV-17-1213-D R0, EV-17-1262-D R0, EV-17-1262-D R3, TF-17-1362-D R0, EV-17-1384-D R0, TF-17-1451-D R1, TF-17-1451-D R2, TF-17-1569-D R0, TF-17-1569-D R1, TF-17-1690-D R0, EV-17-1803-D R0, EV-17-1803-D R1, EV-18-0197-D R0, TF-18-0373-D R0, EV-18-0424-D R0, TF-18-0491-D R0, TF-18-0491- D R1, EV-18-0609-D R0) that support the 2018 annual update. Additional editorial and format changes were made that meet the definition of an inconsequential change per TFC-ENG-SB-C-03 and are GCX-2 for USQ evaluation. 9. TBDs or Holds ☒ N/A 10. Related Structures, Systems, and Components a. Related Building/Facilities ☐ N/A b. Related Systems ☒ N/A c. Related Equipment ID Nos. (EIN) ☒ N/A 242-A EVAPORATOR FACILITIES 11. Impacted Documents – Engineering ☒ N/A Document Number Rev. Title 12. Impacted Documents (Outside SPF): N/A 13. Related Documents ☐ N/A Document Number Rev. Title HNF-15279 02C 242-A EVAPORATOR TECHNICAL SAFETY REQUIREMENTS HNF-2905 00 1998 242-A INTERIM EVAPORATOR TANK SYSTEM INTEGRITY ASSESSMENT REPORT HNF-3327 01 242-A EVAPORATOR LIFE EXTENSION STUDY HNF-3327 00 242-A EVAPORATOR LIFE EXTENSION STUDY HNF-4240 01 ORGANIC SOLVENT TOPICAL REPORT HNF-5183 05N TANK FARM RADIOLOGICAL CONTROL MANUAL HNF-SD-CP-CN-002 00 THE PACKAGE BOILER SITING CALCULATIONS FOR VESSEL OVERPRESSURIZATIONAT 242 A EVAPORATOR FACILITY HNF-SD-PRP-HA-030 05 242-A EVAPORATOR EMERGENCY PLANNING HAZARDS ASSESSMENT HNF-SD-WM-DQO-014 07 242-A EVAPORATOR DATA QUALITY OBJECTIVES HNF-SD-WM-FHA-024 08C FIRE HAZARDS ANALYSIS FOR THE EVAPORATOR FACILITY (242-A) HNF-SD-WM-OCD-015 46 Tank Farms Waste Transfer Compatibility Program HNF-SD-WM-TSR-006 08D TANK FARMS TECHNICAL SAFETY REQUIREMENTS RPP-11736 01 ASSESSMENT OF AIRCRAFT CRASH FREQUENCY FOR THE HANFORD SITE 200 AREA TANK FARMS RPP-13033 07H TANK FARM DOCUMENTED SAFETY ANALYSIS RPP-13384 02 ORGANIC SOLVENT TECHNICAL BASIS DOCUMENT RPP-13482 08 ATMOSPHERIC DISPERSION COEFFICIENTS AND RADIOLOGICAL/TOXICOLOGICAL EXPOSURE METHODOLOGY FOR USE IN TANK FARMS RPP-13750 40 Waste Transfer Leaks Technical Basis Document RPP-15810 15 Enveloping Tank Farm Transfer Pump Power Discharge Head and Flow RPP-27867 08 BUILDING EMERGENCY PLAN FOR 242-A EVAPORATOR RPP-30604 06 Tank Farms Safety Analyses Chemical Source Term Methodology RPP-37897 02 WASTE TRANSFER LEAK ANALYSIS METHODOLOGY DESCRIPTION DOCUMENT HNF-14755 Rev.06E 6/27/2018 - 10:43 AM 1 of 578 Jun 27, 2018 DATE:
Transcript
1 SPF-001 (Rev.D1)
DOCUMENT RELEASE AND CHANGE FORMPrepared For the U.S. Department of Energy, Assistant Secretary for Environmental ManagementBy Washington River Protection Solutions, LLC., PO Box 850, Richland, WA 99352Contractor For U.S. Department of Energy, Office of River Protection, under Contract DE-AC27-08RV14800
TRADEMARK DISCLAIMER: Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof or its contractors or subcontractors. Printed in the United States of America.
Title Name Signature DateClearance Review Curry, Mary P Curry, Mary P 06/27/2018Design Authority Goetz, Tom Goetz, Tom 06/25/2018Checker Lansing, Lisa C Lansing, Lisa C 06/25/2018Document Control Approval Porter, Mary Porter, Mary 06/27/2018Originator Smith, Ryan D Smith, Ryan D 06/25/2018Responsible Engineering Manager Goetz, Tom Goetz, Tom 06/26/2018USQ Evaluator Smith, Ryan D Smith, Ryan D 06/26/2018
8. Description of Change and Justification
Incorporates DSA page changes from negative USQDs (EV-15-0448-D R1, EV-17-0089-D R4, EV-17-0504-D R1, EV-17-0723-D R0, EV-17-1213-D R0, EV-17-1262-D R0, EV-17-1262-D R3, TF-17-1362-D R0, EV-17-1384-D R0, TF-17-1451-D R1, TF-17-1451-D R2, TF-17-1569-D R0, TF-17-1569-D R1, TF-17-1690-D R0, EV-17-1803-D R0, EV-17-1803-D R1, EV-18-0197-D R0, TF-18-0373-D R0, EV-18-0424-D R0, TF-18-0491-D R0, TF-18-0491-D R1, EV-18-0609-D R0) that support the 2018 annual update. Additional editorial and format changes were made that meet the definition of an inconsequential change per TFC-ENG-SB-C-03 and are GCX-2 for USQ evaluation.
9. TBDs or Holds ☒ N/A
10. Related Structures, Systems, and Components
a. Related Building/Facilities ☐ N/A b. Related Systems ☒ N/A c. Related Equipment ID Nos. (EIN) ☒ N/A
242-A EVAPORATOR FACILITIES
11. Impacted Documents – Engineering ☒ N/A
Document Number Rev. Title
12. Impacted Documents (Outside SPF):
N/A
13. Related Documents ☐ N/A
Document Number Rev. TitleHNF-15279 02C 242-A EVAPORATOR TECHNICAL SAFETY REQUIREMENTSHNF-2905 00 1998 242-A INTERIM EVAPORATOR TANK SYSTEM INTEGRITY ASSESSMENT REPORTHNF-3327 01 242-A EVAPORATOR LIFE EXTENSION STUDYHNF-3327 00 242-A EVAPORATOR LIFE EXTENSION STUDYHNF-4240 01 ORGANIC SOLVENT TOPICAL REPORTHNF-5183 05N TANK FARM RADIOLOGICAL CONTROL MANUALHNF-SD-CP-CN-002 00 THE PACKAGE BOILER SITING CALCULATIONS FOR VESSEL OVERPRESSURIZATIONAT 242 A
EVAPORATOR FACILITYHNF-SD-PRP-HA-030 05 242-A EVAPORATOR EMERGENCY PLANNING HAZARDS ASSESSMENTHNF-SD-WM-DQO-014 07 242-A EVAPORATOR DATA QUALITY OBJECTIVESHNF-SD-WM-FHA-024 08C FIRE HAZARDS ANALYSIS FOR THE EVAPORATOR FACILITY (242-A)HNF-SD-WM-OCD-015 46 Tank Farms Waste Transfer Compatibility ProgramHNF-SD-WM-TSR-006 08D TANK FARMS TECHNICAL SAFETY REQUIREMENTSRPP-11736 01 ASSESSMENT OF AIRCRAFT CRASH FREQUENCY FOR THE HANFORD SITE 200 AREA TANK FARMSRPP-13033 07H TANK FARM DOCUMENTED SAFETY ANALYSISRPP-13384 02 ORGANIC SOLVENT TECHNICAL BASIS DOCUMENTRPP-13482 08 ATMOSPHERIC DISPERSION COEFFICIENTS AND RADIOLOGICAL/TOXICOLOGICAL EXPOSURE
METHODOLOGY FOR USE IN TANK FARMSRPP-13750 40 Waste Transfer Leaks Technical Basis DocumentRPP-15810 15 Enveloping Tank Farm Transfer Pump Power Discharge Head and FlowRPP-27867 08 BUILDING EMERGENCY PLAN FOR 242-A EVAPORATORRPP-30604 06 Tank Farms Safety Analyses Chemical Source Term MethodologyRPP-37897 02 WASTE TRANSFER LEAK ANALYSIS METHODOLOGY DESCRIPTION DOCUMENT
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2 SPF-001 (Rev.D1)
13. Related Documents ☐ N/A
Document Number Rev. TitleRPP-48050 01 Technical Basis for Releases from Deflagration or Detonation in the 242-A EvaporatorRPP-48900 00F 242-A Evaporator Hazard Evaluation Database ReportRPP-5924 05 RADIOLOGICAL SOURCE TERMS FOR TANK FARMS SAFETY ANALYSISRPP-7475 08 CRITICALITY SAFETY EVALUATION REPORT FOR HANFORD TANK FARMS FACILITIESRPP-8949 00 PROJECT EXECUTION PLAN FOR 242-A EVAPORATOR LIFE EXTENSION UPGRADESRPP-CALC-23897 09 VFD DRIVEN INDUCTION MOTOR/PUMP PERFORMANCE EVALUATIONRPP-CALC-29700 03 Flammability Analysis and Time to Reach Lower Flammability Limit Calculations for the 242 A EvaporatorRPP-CALC-47411 00 Technical Basis for Release Events Due to Vessel Failure for the 242-A Evaporator FacilityRPP-CALC-50347 00 242A PSV-PB2-1 PRESSURE RELIEF SYSTEM ANALYSISRPP-CALC-52079 00 PSV-RW-3 and BFP-RW-11 ASME B31.1 Analysis, Support Analysis, and PSV-RW-3 Flow AnalysisRPP-CALC-54586 01 SIL Verification Calculation for the 242-A Evaporator C-A-1 Vessel High Level Control SystemRPP-RPT-33306 00A IQRPE INTEGRITY ASSESSMENT REPORT FOR THE 242-A EVAPORATOR TANK SYSTEMRPP-RPT-42119 07 242-A Evaporator PSV-PB2-1 Relief Valve - Functions and Requirements Evaluation DocumentRPP-RPT-51829 02 242-A Evaporator BFP-RW-11 and PSV-RW-3 Backflow Prevention Devices - Functions and Requirements
HAZARDSRPP-RPT-53035 04 242-A Evaporator C-A-1 Vessel Seismic Dump System - Functions and Requirements Evaluation DocumentRPP-RPT-54583 07 Design Analysis Report for the 242-A Evaporator C-A-1 Vessel Flammable Gas Control SystemRPP-RPT-54584 05 Design Analysis Report for the 242-A Evaporator C-A-1 Vessel Waste High Level Control SystemRPP-TE-52377 00 P-B-2 Pump Seal Water Pressure AnalysisRPP-TE-53945 02 Technical Basis for 242-A Safety Instrumented Systems Sensing Parameters and TimersRPP-TE-55027 00 242-A Safety Significant Process Piping Equivalency B31.1-1973/2004 to B31.3-2012WHC-SD-SQA-ANAL-20001 00 MCNPH CALCULATED GAMMA DOSE AT THE 242A EVAPORATOR BUILDINGWHC-SD-SQA-ANAL-20002 00 CALCULATED GAMMA RADIATION AT 242-A EVAPORATORS AREA RADIATION MONITORS AND GAMMA
CONTOUR PLOTS AT SELECTED ELEVATIONSWHC-SD-WM-ER-124 01 THE 242-A EVAPORATOR CRYSTALLIZER TANK SYSTEM INTEGRITY ASSESSMENT REPORTWHC-SD-WM-PE-054 00 242-A CAMPAIGN 94-2 POST RUN DOCUMENT
14. Distribution
Name OrganizationBaxter, Diana NUCLEAR SAFETYBoshers, Kimberly PERFORMANCE ASSURANCEGoetz, Tom NUCLEAR SAFETYLansing, Lisa C NUCLEAR SAFETYSmith, Ryan D NUCLEAR SAFETY
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HNF-14755Revision 6-E
242-A Evaporator Documented Safety Analysis
Prepared by
R. D. SmithWashington River Protection Solutions, LLC
Date PublishedJune 2018
Prepared for the U.S. Department of EnergyOffice of River Protection
Contract No. DE-AC27-08RV14800
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Approved for Public Release; Further Dissemination Unlimited
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EXECUTIVE SUMMARY
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2
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CONTENTS 1 2
3
ES.1 FACILITY BACKGROUND AND MISSION .............................................................ES-14
2.5.4 242-A Evaporator Process Operations ................................................... 2-21 40 2.5.4.1 Feed Preparation .................................................................... 2-23 41 2.5.4.2 Waste Volume Reduction ...................................................... 2-24 42 2.5.4.3 Decontamination of Offgas and Process Condensate............ 2-25 43 2.5.4.4 Interfaces Between Systems .................................................. 2-25 44
2.5.5 Process Flow Diagram for 242-A Evaporator Operation ...................... 2-25 45 2.5.6 Process Chemistry and Physical Chemical Principles ........................... 2-25 46
2.5.7 Ion Exchange ......................................................................................... 2-27 1 2.5.8 Mechanical Process Systems ................................................................. 2-27 2
2.5.8.1 Evaporation System ............................................................... 2-27 3 2.5.8.2 Vapor Condensation and Treatment ...................................... 2-32 4 2.5.8.3 Process Condensate System .................................................. 2-35 5 2.5.8.4 Steam Condensate Monitoring Systems ................................ 2-36 6 2.5.8.5 Vapor Condensation and Treatment System, Operating 7
Limits..................................................................................... 2-38 8 2.5.8.6 Component/Equipment Spares .............................................. 2-39 9 2.5.8.7 Cold Chemical Systems......................................................... 2-39 10 2.5.8.8 AMU Service and Utility Systems and Components ............ 2-41 11 2.5.8.9 HVAC Room Equipment ...................................................... 2-41 12
2.5.9 Instrumentation and Controls ................................................................. 2-42 13 2.5.9.1 Instrumentation and Control Systems ................................... 2-42 14 2.5.9.2 Safety Instrumented Systems ................................................ 2-43 15 2.5.9.3 Process Control Instrumentation ........................................... 2-47 16 2.5.9.4 Instrument Systems and Component Spares ......................... 2-56 17 2.5.9.5 Evaporator Control Room ..................................................... 2-57 18 2.5.9.6 Instrumentation for Safe Operation ....................................... 2-59 19 2.5.9.7 Effluent Monitoring Instruments ........................................... 2-64 20 2.5.9.8 Data Logging ......................................................................... 2-67 21 2.5.9.9 System Interlocks .................................................................. 2-68 22 2.5.9.10 Ventilation Control System ................................................... 2-68 23
2.5.14 Remote and Contact Maintenance Techniques ...................................... 2-80 34 2.6 CONFINEMENT SYSTEMS ............................................................................ 2-80 35
2.6.1 Building Ventilation............................................................................... 2-81 36 2.6.1.1 K1 Ventilation System .......................................................... 2-81 37 2.6.1.2 K2 Ventilation System .......................................................... 2-84 38 2.6.1.3 Chilled Water Cooler............................................................. 2-86 39 2.6.1.4 Vessel Ventilation System..................................................... 2-86 40
2.7 SAFETY SUPPORT SYSTEMS ....................................................................... 2-88 41 2.7.1 Fire Protection Systems ......................................................................... 2-88 42
2.7.1.1 Fire Rated Barriers ................................................................ 2-89 43 2.7.1.2 Water Supply Adequacy and Reliability ............................... 2-89 44 2.7.1.3 Fire Suppression Systems ...................................................... 2-89 45 2.7.1.4 Location of Sprinkler Heads.................................................. 2-90 46
2.7.2 Radiation Protection Systems ................................................................ 2-90 47 2.7.3 Fire Protection Alarms, Lights, and Signs ............................................. 2-91 48
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2.7.4 Communications and Alarms ................................................................. 2-91 1 2.8 UTILITY DISTRIBUTION SYSTEMS ............................................................ 2-91 2
2.8.3 Water ...................................................................................................... 2-94 8 2.8.3.1 Raw Water System ................................................................ 2-94 9 2.8.3.2 Filtered Raw Water and Process Condensate Recycle 10
System ................................................................................... 2-96 11 2.8.3.3 Sanitary Water System .......................................................... 2-99 12
2.8.4 Compressed Air System ......................................................................... 2-99 13 2.8.4.1 Air Compressors (CP-E-1 and CP-E-2) ................................ 2-99 14 2.8.4.2 After-cooler (E-E-6) .............................................................. 2-99 15 2.8.4.3 Air Receiver Tank (R-E-1) .................................................... 2-99 16 2.8.4.4 Compressed Air Distribution ................................................ 2-99 17 2.8.4.5 Safety Considerations and Controls ...................................... 2-99 18
2.8.5 Maintenance Systems........................................................................... 2-100 19 2.9 AUXILIARY SYSTEMS AND SUPPORT FACILITIES .............................. 2-101 20
LIST OF APPENDICES 29 30 31 2A STRUCTURAL SPECIFICATIONS ............................................................................ 2A-i 32 2B RESERVED FOR FUTURE USE ................................................................................. 2B-i 33 2C INTERLOCKS ............................................................................................................... 2C-i 34 35 36
LIST OF FIGURES 37 38 39 Figure 2-1. 242-A Evaporator Facility ................................................................................. F2-1 40 Figure 2-2. Physical Boundary Representing the Scope of this Safety Analysis ................. F2-2 41 Figure 2-3. First Floor Plan .................................................................................................. F2-3 42 Figure 2-4. Second Floor Plan .............................................................................................. F2-4 43 Figure 2-5. Elevations ........................................................................................................... F2-5 44 Figure 2-6. 242-A Evaporator Process Flowsheet ................................................................ F2-6 45 Figure 2-7. Pump Room ....................................................................................................... F2-7 46 Figure 2-8. Evaporator Room ............................................................................................... F2-8 47 Figure 2-9. Condenser Room ................................................................................................ F2-948
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Figure 2-10. 242-A Building Structural Components .......................................................... F2-10 1 Figure 2-11. Ground-Level Aqueous Make Up Room ......................................................... F2-11 2 Figure 2-12. Heating, Ventilation, and Air Conditioning Room .......................................... F2-12 3 Figure 2-13. Process Slurry Reboiler.................................................................................... F2-13 4 Figure 2-14. Typical Pump Room Jumper Arrangement ..................................................... F2-14 5 Figure 2-15. Process Condensate System ............................................................................. F2-15 6 Figure 2-16. Cold Chemical Systems ................................................................................... F2-16 7 Figure 2-17. Flammable Gas Safety Instrument System ...................................................... F2-17 8 Figure 2-18. High-Level Safety Instrument System ............................................................. F2-18 9 Figure 2-19. Evaporator Feed Control System ..................................................................... F2-19 10 Figure 2-20. Vacuum Control ............................................................................................... F2-20 11 Figure 2-21. Steam Condensate Monitoring and Sampling System ..................................... F2-21 12 Figure 2-22. Used Raw Water Monitoring and Sampling System ....................................... F2-22 13 Figure 2-23. K1 Ventilation System Flow Distribution ....................................................... F2-23 14 Figure 2-24. Negative Air Pressure Maintenance................................................................. F2-24 15 Figure 2-25. K1 Heating, Ventilation, and Air Conditioning Exhaust Equipment 16
Pad Plan ........................................................................................................... F2-25 17 Figure 2-26. K1 Heating, Ventilation, and Air Conditioning Exhaust Equipment 18
Monitoring System........................................................................................... F2-29 23 Figure 2-30. K1 Stack Monitoring System ........................................................................... F2-30 24 Figure 2-31. K2 Flow Distribution System .......................................................................... F2-31 25 Figure 2-32. Vessel Ventilation System Components .......................................................... F2-32 26 Figure 2-33. Backup Power System ..................................................................................... F2-33 27 Figure 2-34. Raw Water Supply ........................................................................................... F2-34 28 Figure 2-35. Filtered Raw Water Supply .............................................................................. F2-35 29 30 31
LIST OF TABLES 32 33 34 Table 2-1. Process Flow Material Balances ........................................................................ T2-1 35 Table 2-2. Reserved for Future Use .................................................................................... T2-2 36 Table 2-3. Spare and Alternative Instruments ..................................................................... T2-3 37 Table 2-4. Instrument Air Applications .............................................................................. T2-4 38
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LIST OF TERMS 1 2 3 ALARA as low as reasonably achievable 4 AMU Aqueous Make Up 5 ANSI American National Standards Institute 6 ASCE American Society of Civil Engineers 7 ASME American Society of Mechanical Engineers 8 BCU building control unit 9 CERCLA Comprehensive Environmental Response, Compensation, and Liability Act of 10
1980 11 CFR Code of Federal Regulations 12 DOE U.S. Department of Energy 13 DOV diaphragm-operated valve 14 DSA documented safety analysis 15 DSS double-shell slurry 16 DST double-shell tank 17 Ecology State of Washington Department of Ecology 18 ETF Effluent Treatment Facility 19 FY fiscal year 20 HEPA high-efficiency particulate air 21 HMI human-machine interface 22 HVAC heating, ventilation, and air conditioning 23 IBC®1 International Building Code 24 ICD interface control document 25 ID inside diameter 26 IQRPE independent qualified registered professional engineer 27 ISA International Society of Automation 28 LCU local control unit 29 LERF Liquid Effluent Retention Facility 30 LFL lower flammability limit 31 MCS monitoring and control system 32 MPFL Maximum Permissible Fire Loss 33 NFPA National Fire Protection Association 34 NPH natural phenomena hazard 35 NQA Nuclear Quality Assurance 36 OD outside diameter 37 PC Performance Category 38 PDI pressure differential indicator 39 PPE personnel protective equipment 40 PUREX Plutonium Uranium Extraction (facility) 41 RCRA Resource Conservation and Recovery Act of 1976 42 RCT radiological control technician 43 RTD resistance temperature detector 44 SDC standard design criteria 45
1 IBC and International Building Code are registered trademarks of The International Code Council, Inc., Country Club Hills, Illinois.
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SIS safety instrumented system 1 SSC structures, systems, or components 2 SST single-shell tank 3 TDI temperature differential indicator 4 TEDF Treated Effluent Disposal Facility 5 TOC Tank Operations Contractor 6 UBC Uniform Building Code 7 UPS uninterruptible power supply 8 U.S.C United States Code 9 VCS ventilation control system 10 VFD variable frequency drive 11 WF weight factor 12 WSCF Waste Sample Characterization Facility 13 WVR waste volume reduction 14 WVRF waste volume reduction factor 15
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2.0 FACILITY DESCRIPTION 1 2 3 2.1 INTRODUCTION 4 5 This chapter describes the 242-A Evaporator facility (see Figure 2-1) and operations to support 6 assumptions used in the hazards and accident analyses. These descriptions focus on the major 7 facility features necessary to understand the hazard and accident analyses, not just safety-related 8 structures, systems, and components (SSC). Operations and SSCs of the 242-A Evaporator 9 addressed in this documented safety analysis (DSA) are encompassed within the facility 10 boundaries depicted in Figure 2-2. Chapter 3.0 describes the hazards and accident analyses, and 11 safety classifications of the SSCs; Chapter 4.0 describes the safety-significant SSCs and Specific 12 Administrative Controls in greater detail; and Chapter 5.0 provides the derivation basis for the 13 technical safety requirements. 14 15 The 242-A Evaporator is operated by the Tank Operations Contractor (TOC). The tank farms, 16 which is connected to the 242-A Evaporator, is also managed by the TOC, but has a separate 17 DSA (RPP-13033, Tank Farms Documented Safety Analysis). 18 19 The 242-A Evaporator is located in the 200 East Area of the Hanford Site. Construction 20 extended from 1974 to 1977. Process piping was terminated at the building wall by the original 21 project and continued later to the 241-A and 241-AW tank farms under projects B-102 and 22 B-120. 23 24 The 242-A Evaporator began operations in 1977. Between 1977 and the late 1980s, the 25 242-A Evaporator missions included: 26 27
• Supporting defense-related production of nuclear weapons material; 28 29
• Protecting the environment by concentrating and transferring liquid waste from 30 single-shell tanks (SST) into double-shell tanks (DST); and 31
32 • Managing DST waste by reducing the volume and the number of DSTs required for 33
storage of liquid waste. 34 35 Portions of the 242-A Evaporator were expanded and upgraded in 1983. These modifications 36 added 1,500 ft2 to the 242-A Building and included: 37 38
• Expanding the control room, relocating instrumentation, and adding a new annunciator 39 panel; 40
41 • Expanding the men’s change room and adding a women’s change room; and 42
43 • Adding a pre-engineered lean-to building to house clean and soiled laundry (displaced by 44
other expansions) and a storage area. 45 46
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Floor plans and elevation sketches for the 242-A Evaporator are shown in Figures 2-3 through 1 2-5. Sections 2.4 through 2.9 contain detailed discussions of SSCs and processes. A process 2 flowsheet is shown in Figure 2-6. 3 4 The design life of the 242-A Evaporator as originally constructed was 10 years. In a study based 5 on 1987 waste volume projections, Westinghouse Hanford Company determined that the 6 242-A Evaporator would be required through the year 2000. Engineering studies and design 7 efforts were initiated in fiscal year (FY) 1987 to upgrade the 242-A Evaporator to extend the 8 operating life by 10 years. A major construction outage to incorporate the design changes was 9 scheduled for FY 1990. 10 11 The 242-A Evaporator was placed in temporary shutdown in April 1989, pending determination 12 if process condensate is a mixed waste due to mixed waste being introduced into the DSTs and, 13 consequently, into the 242-A Evaporator. Mixed waste contains both radioactive and hazardous 14 constituents that are classified as dangerous waste by the State of Washington Department of 15 Ecology (Ecology). Subsequent meetings with Ecology concluded that the process condensate 16 stream is a mixed waste stream regulated by Ecology, and further discharges to the 216-A-37-1 17 Crib were eliminated. The determination led to a 5-year shutdown of the 242-A Evaporator until 18 the Liquid Effluent Retention Facility (LERF) basins were constructed for storing process 19 condensate. 20 21 242-A Evaporator operation and treating and disposing of the process condensate are key 22 activities in supporting the goals and milestones defined in DOE/RL-89-10, Hanford Federal 23 Facility Agreement and Consent Order. The LERF basins store process condensate prior to 24 treatment in support of 242-A Evaporator operation. Treatment facilities were constructed to 25 reduce the concentrations of ammonia, residual organics, and dissolved radionuclides in the 26 process condensate to levels that permit direct disposal of the treated liquid effluent to the 27 Hanford Site soil column. 28 29 242-A Evaporator upgrades were initiated during the shutdown pending resolution of the 30 dangerous waste issue. The 242-AB Building was constructed to house the upgraded control 31 room (Room 18) and an electrical room (Room 19). The upgrades were completed in FY 1993, 32 and operations restarted in April 1994. 33 34 Other 242-A Evaporator changes include rerouting steam condensate from the 207-A Retention 35 Basins to the Treated Effluent Disposal Facility (TEDF) in 1997, rerouting the condenser cooling 36 water from B-Pond to TEDF in 1997, and installing a new package boiler system in 1998. 37 38 The current and future mission of the 242-A Evaporator is to support environmental restoration 39 and remediation of the Hanford Site by optimizing the 200 East and West areas DST waste 40 volumes in support of the tank farm and vitrification contractors. To support this mission, an 41 additional life extension study (HNF-3327, 242-A Evaporator Life Extension Study) was 42 prepared to identify the work scope needed to extend the facility life through 2016. This study 43 was revisited in January 2001 due to a need for the facility through 2019 (HNF-3327, 44 Engineering Study for the 242-A Life Extension Upgrades for Fiscal Years 2002 thru 2005). 45
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A report was issued in 2001 (included as HNF-3327, Appendix S) to validate the scope identified 1 in 1998 and identify any new scope not previously addressed. A Project Execution Plan 2 (RPP-8949, Project Execution Plan for 242-A Evaporator Life Extension Upgrades) was issued 3 in May 2002 to provide guidance in execution of the life extension projects. 4 5 As of July 2009, the following activities were completed: 6 7
• Replacement of the slurry jumper (FY 2003), which included a new slurry pump P-B-2 8 discharge relief valve and DI-CA1-3, a coriolis mass flow density meter; 9 10
• Replacement of several brass valves on the process condensate system (FY 2003); 11 12
• Removal of the ion exchange columns (FY 2003); 13 14
• Replacement of the ion exchange column room and non-process area roofs (FY 2003); 15 16
• Replacement of the E-C-2 and E-C-3 condensers and associated steam jets (FY 2004); 17 18
• Replacement of the electric compressors and installation of an associated closed loop 19 cooling system (FY 2006); 20 21
• Replacement of 24 instruments, including pressure, flow, and I/P transducers (FY 2007); 22 23
• Upgrade of the supply side of the K1 and K2 ventilation systems, including control and 24 distribution equipment and replacement of steam heating and evaporative cooling with 25 electric heat and refrigerant cooling (FY 2008); 26 27
• Upgrade of the monitoring and control system (MCS) (FY 2008); and 28 29
• Removal of the electric air compressors as part of the upgrade to the plant air system 30 (FY 2009). 31
32 In 2010, the following activities were completed: 33 34
• Installation of replacement air compressors; 35 36
• Removal of the out-of-service de-superheater and associated instrumentation; 37 38
• Installation of a new PC-5000 leak detection system upgrade, encasement catch tank, and 39 software modifications; 40 41
• Replacement of various instruments throughout the facility; and 42 43
• Replacement and safety qualification of the slurry pump P-B-2 overpressure protection 44 system as credited in RPP-13033. 45
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In 2011, the following activities were completed: 1 2
• Installation of a new K1 ventilation system stack and high-efficiency particulate air 3 (HEPA) filter banks; 4 5
• Modifications to the RC-1 and RC-2 sampling systems; and 6 7
• Installation of a new dip tube flushing system. 8 9
In 2012, modifications were made to the steam condensate system piping and steam traps were 10 replaced. Progress and imminent work plans on other upgrade projects are tracked through the 11 upgrades project schedule. 12 13 14 2.2 REQUIREMENTS 15 16 The design codes, standards, regulations, and U.S. Department of Energy (DOE) orders relevant 17 to this chapter, and required for establishing the safety basis for the 242-A Evaporator, are as 18 follows: 19 20
• Title 10, Code of Federal Regulations, Part 830 (10 CFR 830), “Nuclear Safety 21 Management” 22 23
• DOE G 421.1-2, Implementation Guide for Use in Developing Documented Safety 24 Analyses to Meet Subpart B of 10 CFR 830 25 26
• DOE-STD-3009-94, Preparation Guide for US Department of Energy Nonreactor 27 Nuclear Facility Documented Safety Analysis 28 29 30
2.3 FACILITY OVERVIEW 31 32 This section provides a brief overview of 242-A Evaporator configuration and the evaporation 33 process. 34 35 36 2.3.1 Facility Configuration 37 38 The 242-A Evaporator is located in the 200 East Area. The following four principal structures 39 make up the 242-A Evaporator: 40 41
• 242-A Building, main process building 42 • 242-AB Building, adjacent control room building 43 • 242-A-81 Building, water services building 44 • K1 Ventilation HEPA filter banks and stack structure 45
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The principal process components of the 242-A Evaporator system are illustrated in Figures 2-7 1 through 2-9. These components include the reboiler, evaporator vessel C-A-1, recirculation 2 pump P-B-1 and recirculation pipe loop, slurry pump P-B-2, condensers, jet vacuum system, and 3 the process condensate tank TK-C-100. This equipment is located in the 242-A Building, which 4 consists of two adjoining but independent structures. One structure houses the processing and 5 service areas, rooms A through G. The other structure contains rooms 1 through 17 and houses 6 operating and personnel support areas, such as change rooms and supply room (Figure 2-3). 7 Under Project B-534, a new building, 242-AB, was constructed to house the upgraded control 8 room and an electrical room, rooms 18 and 19, respectively. 9 10 A computer-based MCS is located in the 242-AB Building control room. The MCS is used to 11 operate and monitor the 242-A Evaporator and various tank farm facilities as described in 12 Sections 2.4 and 2.5. Utilities and services supplied to the 242-A Evaporator include electrical 13 power, water, and steam. Electrical power is provided by the electrical substation and a backup 14 diesel generator. The backup diesel generator electrical cabinet contains a transfer switch that 15 transfers power from the backup generator if normal power is lost. (Note: The diesel generator 16 and transfer switch are not required to be available during evaporator operations). Water is 17 provided from the 282-EC Building to the 242-A-81 Water Services Building. Steam used in the 18 242-A Evaporator process is provided by package boilers, located in the 242A-BA boiler annex, 19 which are operated by an independent contractor. A brief discussion of the package boiler 20 system is provided in Section 2.9.4. 21 22 The 242-A Evaporator feed is staged in the evaporator feed tank, 241-AW-102 (AW-102), a 23 one-million-gallon DST, and is pumped from feed tank 241-AW-102 to the 242-A Evaporator 24 through an underground-encased pipeline. Miscellaneous solutions are returned to feed tank 25 241-AW-102 via three underground drain lines (two of which are encased) that run from the 26 242-A Building to the tank drain pit. 242-A Evaporator slurry is pumped to a tank farm valve pit 27 via underground-encased piping. The slurry can be directed to a specific DST by tank farm 28 personnel from the valve pit using the tank farm transfer system. The tank farm transfer system 29 is connected to the 242-A Evaporator in-facility process piping at the exterior walls of the 242-A 30 Evaporator, which constitutes the boundary between the two facilities. The tank farm transfer 31 system is described in RPP-13033. Figure 2-2 shows the general location of the piping runs. 32 33 242-A Evaporator process condensate, steam condensate, and cooling water (called used raw 34 water) streams are transferred to other waste handling facilities. Process condensate is 35 transferred to LERF via PC-5000, a 4,950-foot underground transfer line consisting of a 3-inch 36 transfer line inside a 6-inch containment pipe. 37 38 Both the primary and encasement lines are constructed of fiberglass-reinforced epoxy thermoset 39 resin. Electronic leak detection is provided at 1000-foot intervals along the transfer line, and 40 swab risers are provided every 100 feet between the leak detection elements. Steam condensate 41 and cooling water are transferred via separate underground transfer lines to an underground 42 36-inch transfer line connected to TEDF Pump Station 3. The TEDF transfer system 43 is discussed in RPP-RPT-59117, 200 Area Treated Effluent Disposal Facility Interface Control 44 Document. 45 46
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This DSA is limited in scope to systems and components located within the exterior walls of the 1 242-A Evaporator, ventilation systems, 242-A-81 water supply, backup electrical system, and the 2 PC-5000 process condensate transfer line. Discussion of facilities and utilities that support the 3 242-A Evaporator are included in this DSA to clarify the interface or relationship between the 4 242-A Evaporator and tank farms, LERF, TEDF, and the package boiler system. 5 6 7 2.3.2 Process Overview 8 9 The 242-A Evaporator is designed to reduce waste volume and therefore the number of DSTs 10 required to store liquid waste generated at the Hanford Site. The process uses a conventional, 11 forced-circulation, vacuum evaporation system operating at low pressure (approximately 60 torr) 12 and low temperature (approximately 122°F) to concentrate radioactive waste solutions. 13 14 The waste feed is pumped from feed tank 241-AW-102 through an underground-encased feed 15 line to the 242-A Evaporator, and subsequently into the C-A-1 vessel for processing. The waste 16 feed is concentrated in the C-A-1 vessel to a specified concentration creating product slurry and 17 water vapor. The slurry is transferred from the 242-A Evaporator through underground-encased 18 piping to the 241-AW-B valve pit in the 241-AW Tank Farm. The slurry is generally routed 19 from the valve pit to tank 241-AW-106, or to tanks in the AP Tank Farm, but can be routed to 20 other DSTs in the 200 East Area. Process offgases and water vapor are passed through one 21 primary and two secondary condensers, creating the process condensate and a gaseous effluent. 22 Gaseous effluents are filtered and released to the environment from the vessel ventilation exhaust 23 system. Process condensate is collected in process condensate tank TK-C-100 and pumped 24 directly to LERF via the PC-5000 transfer line, or used in the process condensate recycle system. 25 In the past, if the process condensate required additional cesium and strontium removal it was 26 processed through ion exchange columns before discharge to the LERF. However, the ion 27 exchange columns have been removed because treatment is provided by the Effluent Treatment 28 Facility (ETF). Cooling water from the process vapor condensers and the steam condensate 29 stream are discharged to TEDF Pump Station 3. 30 31 Fundamental material balances associated with the systems described in this section are given in 32 Table 2-1 and show the characteristics of the systems, inputs to, and outputs from the 33 242-A Evaporator that are basic for understanding the processes in the facility. 34 35 A detailed discussion of the 242-A Evaporator process is provided in Section 2.5. 36 37 38 2.4 242-A EVAPORATOR STRUCTURES 39 40 This section describes the 242-A Evaporator SSCs and their functions. 41 42 The principal process components of the 242-A Evaporator system are located in the 43 242-A Building, which is comprised of two adjoining but independent structures designated as 44 Y and Z as shown in Figure 2-10. Structure Y contains processing and service areas and is a 45 reinforced concrete shear wall and slab structure with concrete mat footing in below grade 46
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regions and spread footings elsewhere. Structure Z, which is separated from Structure Y by a 1 seismic joint, contains operating and personnel support areas, such as change rooms and a 2 supply room. 3 4 The 242-A Building is ~75 ft. wide by 108 ft. long and 62 ft. above grade at its highest point. 5 A portion of the building extends 10 ft. below grade. 6 7 The 242-A Building is compartmentalized by physical barriers and ventilation systems into three 8 areas: process, service, and operations. The process area includes the evaporator room, pump 9 room, condenser room, and ion exchange room. The service area includes the Aqueous Makeup 10 (AMU) room, load-out and hot-equipment storage room, loading room, and the heating, 11 ventilation, and air conditioning (HVAC) room. The operations areas located in the 12 242-A Building include the control room, change rooms, lunchroom, office, and storage rooms. 13 14 The roof of Structure Z consists of metal decking supported by structural steel members 15 spanning to reinforced concrete block walls. The foundation consists of continuous strip 16 footings. This portion of the 242-A Building was designed and constructed in accordance with 17 Uniform Building Code (UBC) specifications in effect at the time. Appendix 2A lists the codes 18 and standards applied in constructing the original 242-A Evaporator and Project B-534 upgrades. 19 20 The 242-AB Building is an addition to Structure Z of the 242-A Building and is of similar 21 design and construction. It shares a common wall with the 242-A Building and is 22 45 ft.-4 in. by 40 ft. by 12 ft. high. The control room and the electrical room are located in the 23 242-AB Building. 24 25 26 2.4.1 Detailed Structure Descriptions 27 28 The following sections describe individual areas in the 242-A Building and 242-AB Building 29 and include essential dimensions, functions, features, and components. 30 31 2.4.1.1 Pump Room (B). The pump room (Figure 2-7) is 22 ft.-2 in. by 18 ft. The ceiling of 32 the room is 12.5 ft. above grade and consists of four removable concrete cover blocks that allow 33 crane access from the overhead gallery. A section of the pump room floor, 22 ft.-2 in. by 9 ft., is 34 10 ft. below grade and contains a sump. The pump room shares a common wall with the 35 evaporator room through which the 28 in. recirculation line passes. Shielding walls of the pump 36 room are 1 ft-10 in. thick concrete. A 2 ft.-5 in. by 2 ft.-5 in. oil-filled shielding window is 37 located in the east wall for surveillance and crane operation from the AMU room. The floor of 38 the pump room is lined with stainless steel and the walls are painted with a barrier coating to 39 facilitate decontamination. 40 41 A series of nozzles are located on the north, west, and south walls to provide services and liquid 42 transfer routes for the cell equipment. Jumpers are installed between the equipment and the wall 43 nozzles. 44 45
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Access to the pump room is restricted except under certain conditions to allow maintenance 1 work. A free-swinging door opens from the -10 ft. level of the evaporator room into the pump 2 room for personnel access. 3 4 Pump room systems and components introduce evaporator feed, recirculate in-process slurry, 5 withdraw slurry, and transfer the product to a tank farm valve pit. Feed material for the process 6 is pumped from feed tank 241-AW-102 to the pump room. It is routed through jumpers to the 7 28-in. recirculation line where it enters the process. The recirculation pump recirculates the 8 slurry through the reboiler to C-A-1 vessel and back to the reboiler. Slurry is withdrawn from 9 the process and routed via the C-13 jumper to slurry pump P-B-2 to the transfer piping. The 10 slurry can be transferred either by gravity drainage or by the slurry pump through evaporator 11 jumpers and the tank farm’s transfer system to any tank farm DST in the 200 East area. 12 13 The principal components located in the pump room are recirculation pump P-B-1, slurry pump 14 P-B-2, and process jumpers. Components of the process jumpers in the pump room, and what 15 function those components serve, include the following. 16 17 Feed line jumper components: 18 19
• Feed valve HV-CA1-1 – The purpose of this valve is to isolate feed flow from the 20 recirculation line. The valve actuator is timed to a slow actuation speed to prevent 21 damaging water hammer in the feed line. 22 23
• Multipurpose instrument FE-CA1-1 – This is a coriolis meter, and is capable of detecting 24 the feed flow rate and feed density of waste coming into the 242-A process. 25
26 Slurry line jumper components: 27 28
• HV-CA1-2 and HV-CA1-2A valves – The purpose of these valves is to isolate slurry 29 flow from the 242-A Evaporator and to allow flush water flow to the C-A-1 vessel and to 30 tank farms. The valve actuators are timed to a slow actuation speed to prevent damaging 31 water hammer in the slurry line. 32 33
• Pressure relief valve PSV-PB2-1 – This relief valve prevents overpressurization of both 34 tank farms piping and 242-A slurry jumpers. A discharge line from the relief valve is 35 routed to the pump room sump and is sized to ensure adequate relief flow for the relief 36 valve. 37 38
• Vacuum breaker PSV-CA1-4 – This vacuum breaker prevents column separation in the 39 slurry line, which can cause a damaging water hammer in the slurry line. Vacuum 40 breaker PSV-CA1-4 performs a safety function in the tank farms DSA to prevent the loss 41 of the safety function of tank farm safety-significant SSCs from flow transients (i.e., 42 water hammers) caused by vapor bubble collapse (see RPP-13033, Tank Farms 43 Documented Safety Analysis, Section 4.4.6). 44
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The Pump Room Sump is a 5-ft. by 5-ft. by 6-ft. stainless steel lined sump and has a capacity of 1 approximately 1,125 gallons. The sump is equipped with three dip tube lines which are used to 2 determine the sump level, the density of the sump contents, and the corrected weight-factor of the sump. 3 These parameters are indicated by the MCS. Each one of these dip tube lines is supplied with 20 psig 4 instrument air via their respective flow indicating controller (FIC-SUMP-1, 2 & 3). Raw water can be 5 supplied to the sump through the makeup valve, HV-SUMP. The sump collects liquid waste and 6 transfers it to the evaporator feed tank 241-AW-102 using the sump steam jet pump (jet ejector), J-B-1. 7 8 The purpose of the pump room sump steam jet pump (J-B-1) is to pump the contents of the pump room 9 sump to the feed tank (241-AW-102). Liquid waste that collects in the sump is normally pumped to the 10 10-in. overflow line using sump jet ejector, J-B-1 (works just like a steam jet vacuum air ejector). 11 12 The sump is pumped manually with the MCS to maintain level in the sump between the high and low 13 level alarm set points. The operator manually initiates the operation of the sump jet gang valve 14 assembly to valve 90 psig steam to the sump jet ejector J-B-1. After J-B-1 pumps the sump level down 15 to the desired level the sump jet gang valves are repositioned to block the steam from flowing to J-B-1. 16 The sump jet gang valve assembly is then purged with process air (venting to the pump room) in order 17 to cool and dry the lines. After the purge, HV-AIR-SUMP-1 closes and the valve assembly remains in 18 its normal standby condition (vented to the pump room). 19 20 2.4.1.2 Evaporator Room (A). The evaporator room (Figure 2-8) is 22 ft.-2 in. by 21 25 ft.-4 in. It is 71 ft.-6 in. from floor (at 10 ft. below grade) to ceiling (61 ft.-6 in. above grade) 22 with metal grating work platforms at elevations of 30 ft.-6 in. and 40 ft.-6 in. The ceiling/roof 23 consists of removable concrete cover blocks. This type of construction could be classified as 24 Type I noncombustible fire-resistive in accordance with National Fire Protection Association 25 (NFPA) 220, Standards on Types of Building Construction. Construction is massive reinforced 26 concrete, but doors in the partitions do not have a fire resistance rating and wall and ceiling 27 penetrations are not sealed to maintain a fire resistance rating. The cover blocks are sealed in 28 place and have not been removed since the facility was constructed. The walls are 1 ft.-10 in. 29 thick concrete to provide radiation shielding. Wall penetrations allow the 42-in. vapor line to 30 enter the condenser room and the 28-in. recirculation line to enter the pump room and return to 31 the evaporator room. Two airlocks, one at grade and one at 40 ft.-6 in., allow personnel access 32 to the evaporator room from the building exterior. Ladders extend from the floor to the work 33 platform at elevation 40 ft.-6 in. Access to the evaporator room is restricted except under certain 34 conditions to allow maintenance work. Process equipment in the evaporator room evaporates 35 water from process slurry until the required waste volume reduction is achieved. Evaporator 36 room components include the reboiler and the C-A-1 vessel. 37 38 2.4.1.3 Condenser Room and Ion Exchange Room (C and D respectively). The 39 condenser room (Figure 2-9) is 24 ft. by 27 ft. Like the adjacent evaporator room, the condenser 40 room is 71 ft.-6 in. from floor (at 10 ft. below grade) to ceiling (at 61 ft.-6 in. above grade). 41 There are metal grating work platforms at elevations 0.0 in., 30 ft.-6 in., 40 ft.-6 in., and 42 50 ft.-6 in., with stairs connecting the platforms. The ceiling/roof consists of removable concrete 43 cover blocks covered with Type A roofing. The cover blocks were removed temporarily in 1990 44 when the primary condenser was replaced. The condenser room shares a common wall with the 45 evaporator room through which the 42-in. vapor line enters. The wall is 1 ft.-10 in. thick to 46 provide radiation shielding. The other three condenser room walls are 1-ft. thick concrete. 47
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1 The condenser room is entered from the survey corridor through a personnel airlock at the 2 0 ft. elevation. Access from the exterior of the facility is through a set of doors at the 40 ft.-6 in. 3 elevation. A door at the 50 ft.-6 in. elevation provides access to the roof via an exterior 4 wall-mounted ladder. These doors are not used on a routine basis and are not designed as 5 airlocks. 6 7 The north wall of the condenser room at the -10 ft. level has a small door to the ion exchange 8 room, which is 6 ft. by 9 ft. The enclosure is 18 ft.-8 in. from the floor (at -7.0 ft.) to the ceiling 9 (at 11 ft-8 in.). The ceiling/roof consists of removable concrete cover blocks covered with 10 roofing. The walls of the enclosure are 1-ft. thick concrete. 11 12 The Ion Exchange Room houses the ion exchange column. The ion exchange column is out of 13 service and has been removed. 14 15 Process equipment in the condenser room pulls the vacuum on the C-A-1 vessel and condenses 16 water vapor and filters non-condensables before venting the products to the atmosphere through 17 the vessel vent system. The tank in the condenser room stores process condensate that is reused 18 in the process for spray to clean the de-entrainment pads, and water seals on recirculation pump 19 P-B-1 and slurry pump P-B-2. Steam condensate flow is measured in the steam condensate weir 20 box TK-C-103, and then normally sent to TEDF. 21 22 Condenser room components include condensers, steam jet eductors, filters, and tanks. 23 24 2.4.1.4 Load-Out and Hot-Equipment Storage Room (F). The load-out and 25 hot-equipment storage room is 22 ft.-2 in. by 12 ft. by 36 ft.-4 in. high. The floor is at elevation 26 0 ft. and contains two sump pits 36 in. in diameter and ~4 ft. deep lined with stainless steel. One 27 pit, designated the decontamination sump, is equipped with four fixed spray nozzles for cleaning 28 equipment with decontamination solutions. Both pits drain to the pump room sump via 3-in. 29 drain lines. The load-out and hot-equipment storage room is open to the crane gallery. The 30 north, east, and west walls are constructed of 1 ft.-10 in. thick concrete. The south wall is 1-ft. 31 thick. A door in the south wall permits entry from the loading room. A ladder on the north wall 32 provides access to the top of the pump room cover blocks. A 4-in. high curb is located at the 33 door to prevent any liquid spills from reaching the loading room. 34 35 The load-out and hot-equipment storage room serves as a decontamination and maintenance area 36 in support of pump room operations and contains sampling equipment for sampling the 37 evaporator process slurry. 38 39 The sample enclosure is located in the northwest corner of the room. It is constructed of 1-in. 40 carbon steel plate and has 2-in. thick lead shielding on the front and side faces and 0.5-in. thick 41 lead shielding on top. The enclosure contains two identical sampling devices, one for evaporator 42 feed, and one for process slurry. The feed sampler is isolated and abandoned in place. 43 Instrument air and hot water are supplied to the sample enclosure for operating the samplers and 44 flushing, respectively. 45 46
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2.4.1.5 Loading Room (G). The loading room is 23 ft.-10 in. by 12 ft. The floor is at 1 elevation 0 ft. and contains a 3-in. floor drain to the pump room sump. The ceiling is ~11 ft. 2 high and consists of a horizontally installed, roll-up, nylon-vinyl, curtain-type door. With the 3 draft curtain rolled back, the loading room is open to the crane gallery. The walls are 1-ft. thick 4 concrete. The loading room is accessed from the AMU room through personnel airlocks located 5 at ground level and at the top of the stairs from the AMU mezzanine, or from the building 6 exterior through the ground level 12 ft. by 15 ft. roll-up door. 7 8 The loading room serves as a loading dock to support pump room operations and contains no 9 installed equipment. 10 11 2.4.1.6 Aqueous Makeup Room (E). The ground-level AMU room (Figure 2-11) is 27 ft. 12 by 24 ft. and 22 ft. from floor to ceiling. Stairs lead to a metal-grate mezzanine at elevation 13 12 ft.-8 in. and from there up to the HVAC room entry and to an airlock to the bridge crane 14 service platform. The AMU room shares a common wall with the loading room, load-out and 15 hot-equipment storage room, pump room, and the associated crane gallery. That portion of the 16 wall common with the pump room and load-out and hot-equipment storage room is 1 ft.-10 in. 17 thick concrete. All other walls are 1-ft. thick concrete. 18 19 The common wall between the loading room, load-out and hot-equipment storage room, and 20 pump room has four viewing windows for crane operation. The pump room window was 21 discussed in Section 2.4.1.1. The three other windows are located at the mezzanine level. Two 22 windows, one located above the pump room and one above the load-out and hot-equipment 23 storage room, are oil-filled shielding windows identical in design to the pump room window. 24 The third window, located above the loading room, is not oil filled, but is lead glass providing 25 the required shielding. 26 27 There are three doors in the AMU room. A standard door between the AMU room and the 28 survey corridor provides routine access. A 10 ft. by 10 ft. sliding door with an integral 3 ft. by 29 7 ft. access door is located in the south wall. A personnel airlock located in the southwest corner 30 provides controlled access to the loading room. 31 32 The function of the AMU room is receipt (or makeup), storage, and transfer of antifoam and 33 decontamination solutions. It also serves as an operating area for the bridge crane. 34 35 The systems and components in the AMU room include the compressed air system, K2-5-2 36 exhaust fan, fire protection system components, electrical system components, and three 37 chemical storage tanks. 38 39 2.4.1.7 Heating, Ventilation, and Air Conditioning Room (H). The HVAC room 40 (Figure 2-12) measures 24 ft. by 44 ft.-10 in. and is located above the AMU room. It shares a 41 common wall with the loading room, load-out and hot-equipment storage room, and the 42 associated crane gallery above the pump room. That portion of the wall common with the 43 load-out and equipment storage room and associated crane gallery above the pump room is 44 1 ft.-10 in. thick concrete. All other walls are 1-ft. thick concrete. The east wall contains a 6 ft. 45
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by 8.5 ft. louvered air supply vent. The ceiling/roof of the room is concrete with insulated 1 built-up Type A roofing. 2 3 The HVAC room is entered from a staircase leading up from the AMU room mezzanine. A 5 ft. 4 by 7 ft. equipment door in the south wall opens to the building exterior and a personnel door in 5 the east wall opens to the building exterior leading up to the building roof or to the ground by 6 ladder and stairs. 7 8 The HVAC room contains equipment to supply conditioned air to the K1 and K2 ventilation 9 systems. 10 11 Section 2.6 describes both the K1 and K2 ventilation systems in detail. 12 13 2.4.1.8 Miscellaneous Areas. Miscellaneous support areas in the 242-A Building are 14 described below. 15 16 2.4.1.8.1 Men’s and Women’s Change Rooms. The men’s and women’s change rooms 17 contain sinks, toilets, showers, and lockers for personnel clothing. Note that ‘change rooms’ is a 18 misnomer; personal protective equipment (PPE) is not allowed in the change room. It is donned 19 near the radiation area entry and removed at control points. Water to the change rooms is 20 supplied from the sanitary water system and drains unmonitored to the sanitary sewer system. 21 22 2.4.1.8.2 Personal Protective Equipment Receiving and Shipping Containers. Clean PPE is 23 stored in bulk outside the 242-A Building in steel shipping containers. PPE that is ready for use 24 is staged in appropriate areas. Used PPE is removed at control points, bagged, surveyed for 25 radioactive contamination, and shipped to the laundry facility. 26 27 2.4.1.8.3 Survey Corridor. The survey corridor is located at the entry/exit points for the AMU 28 room and condenser room. This area serves as a base for radiological control technicians (RCT) 29 supporting 242-A Evaporator operations. A whole-body frisker is located in the survey corridor. 30 31 2.4.1.8.4 Office and Lunchroom. Office space and a lunchroom are provided for staff. 32 33 2.4.1.9 Control Room. The control room is located in the 242-AB Building. The 242-AB 34 Building is 45 ft.-4 in. by 40 ft. and shares a common wall with the 242-A Building. The roof 35 assembly, which has unprotected supporting steel, does not have a fire resistive rating. This type 36 of construction is classified as Type II (000) noncombustible construction in accordance with 37 NFPA 220. An interior wall divides the building into two areas, a 33 ft.-4 in. by 40 ft. control 38 room and a 12 ft. by 40 ft. electrical room. Control room access is through two doors, one of 39 which opens to the outside, and a third door which provides access to the electrical room. 40 41 The control room houses the MCS for the 242-A Evaporator and serves as a monitoring point for 42 some tank farm equipment. 43 44
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2.4.1.10 242-A-81 Water Services Building. The 242-A-81 Water Services Building is 1 located south of the 242-A Evaporator. It is a pre-engineered structure measuring 28 ft. by 20 ft. 2 by 10 ft. high. The floor is a 6-in. thick concrete slab sloped to a 3 ft. by 3 ft. by 3 ft. central 3 sump pit. The 242-A-81 Water Service Building supplies all the raw water to the 242-A 4 Evaporator for processes and operations support. 5 6 2.4.1.11 207-A Retention Basins and 207-A Building. The 207-A Building and 207-A 7 Retention Basins were support facilities used for temporary storage of 242-A Evaporator process 8 condensate and steam condensate. 242-A Evaporator process condensate is now sent to the 9 LERF, where it is stored temporarily prior to treatment at the 200 Area ETF. The steam 10 condensate is discharged directly to the TEDF. The 207-A Retention Basins and 207-A Building 11 have been physically isolated from the 242-A Evaporator Building and are no longer used. 12 13 The 207-A Retention Basins and the 207-A Building has been re-assigned to a separate project 14 and/or contractor for remediation. 15 16 2.4.1.12 Backup Diesel Generator. The backup diesel generator is described in 17 Section 2.8.1. 18 19 20 2.4.2 Structural and Mechanical Design Criteria 21 22 The 242-A Evaporator (Project B-100) was designed and constructed in 1977 in accordance with 23 Hanford Plant Standard Design Criteria (SDC)-4.1, Standard Architectural – Civil Design 24 Criteria: Design Loads for Structures, which established the design loads and acceptance 25 criteria for all permanent Hanford Site facilities constructed at that time. The standard was 26 revised in September 1989 (SDC-4.1, Rev. 11; Standard Architectural – Civil Design Criteria: 27 Design Loads for Facilities). The current design standard for the 242-A Evaporator is 28 TFC-ENG-STD-06, Design Loads for Tank Farm Facilities. A comparison of the 29 242-A Evaporator design to criteria defined in SDC-4.1, Rev. 11, and TFC-ENG-STD-06 is 30 provided in RPP-RPT-52517, 242-A Evaporator Facility Assessment for Performance Category 31 2 Natural Phenomena Hazards, which concludes that the requirements of TFC-ENG-STD-06 for 32 Performance Category (PC)-2 facilities are met. 33 34 When the 242-A Evaporator was constructed, all process piping was terminated at the building 35 wall. It was subsequently extended to the 241-A and 241-AW tank farms under two separate 36 projects: B-102 and B-120. 37 38 DOE/RL-90-42, Hanford Facility Dangerous Waste Permit Application, 242-A Evaporator, 39 (Part B) was submitted to the state of Washington in June 1991. A revised Part B was submitted 40 in July 1997 and incorporated into the Hanford Site Permit in January 1998. 242-A Evaporator 41 restart was covered under an Interim Status Permit Application (Part A). An integrity 42 assessment was performed in 1992-93 to confirm integrity of vessels, piping, and secondary 43 containment concrete as part of the Dangerous Waste Permit Application. The integrity 44 assessment (WHC-SD-WM-ER-124, The 242-A Evaporator/Crystallizer Tank System Integrity 45
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Assessment Report) included ultrasonic testing of vessel wall thickness, and concluded that all 1 tank and containment systems were fit for use. 2 3 A second integrity assessment (HNF-2905, 1998 242-A Interim Evaporator Tank System 4 Integrity Assessment Report) reconfirmed that all systems were fit for use. A third integrity 5 assessment performed in 2007 (RPP-RPT-33306, IQRPE Integrity Assessment Report for the 6 242A Evaporator Tank System) again confirmed that all systems were fit for use. The 7 independent qualified registered professional engineer (IQRPE) recommended that the next 8 integrity assessment be performed no later than 10 years after submittal of the integrity 9 assessment report. This recommendation is based on the results of the ultrasonic test analysis 10 that showed the “minimum remaining life” for all the equipment tested was greater than 11 20 years. 12 13 TFC-ENG-STD-06 establishes the current design loads and acceptance criteria for use in 14 designing new and evaluating existing TOC facilities, which includes the 242-A Evaporator. 15 16 DOE-STD-1020-2016, Natural Phenomena Hazards Analysis and Design Criteria for DOE 17 Facilities, identifies requirements applicable to SSCs based on life-safety or safety classification 18 established by safety analysis. The Hanford TOC implements the natural phenomena hazard 19 (NPH) requirements of DOE-STD-1020-2016 through TFC-ENG-STD-06. 20 21 A PC-2 classification was used as the design (evaluation) basis in RPP-RPT-52517. The 22 242-A Evaporator building (main building), excluding the control room, with areas bounded by 23 gridlines A to C and 1 to 3 (H-2-69269 & H-2-69272) meets the PC-2 NPH requirements per 24 RPP-RPT-52517. In accordance with the International Building Code (IBC 2009, in place at the 25 time of analysis), American Society of Civil Engineers (ASCE) 7-05, Minimum Design Loads 26 for Buildings and Other Structures, has been used in RPP-RPT-52517 to determine applicable 27 loading associated with snow, wind, and seismic NPH. Site specific ash NPH is also considered 28 in RPP-RPT-52517. PC-2 is used as the design (evaluation) basis accident for the 242-A 29 Evaporator safety-significant SSCs (i.e., there are no 242-A Evaporator safety-class SSCs). 30 31 2.4.2.1 Evaporation System Safety Criteria and Assurance. The following features 32 provide personnel and environmental protection from radiological contamination and exposure to 33 radiation. They also provide the means of ensuring a safe system as constructed, operated, and 34 maintained. 35 36 The cell walls and removable cover blocks attenuate radiation during normal operating 37 conditions to a maximum contact dose rate of 0.5 mrem/hr. 38 39 The 242-A Evaporator design is based on the 242-S Evaporator design, in which the control 40 room was located closer to the C-A-1 vessel and the solutions being evaporated contained much 41 higher concentrations of radioactive material. The original 242-A Evaporator radiological design 42 criterion was 0.5 mrem/hr in the control room. Current 242-A Evaporator layout with the 43 relocated control room, and much lower concentration of radioactive material in the slurry 44 because the mission has changed, and significantly reduced operating time in any given year, 45
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result in very low personnel radiation doses. For example, a person stationed in the control room 1 for 2,000 hr/yr would receive less than 100 mrem. 2 3 Exposure of maintenance personnel to radiological and chemical hazards is reduced to ALARA 4 by flushing the process equipment and piping, spray wash down of the equipment exterior and 5 cell walls, and disposing of flush effluent to feed tank 241-AW-102. 6 7 Extensive radiation monitoring and process control instrumentation are provided for this system 8 to protect personnel and the environment and to indicate abnormal process conditions. Radiation 9 detectors initiate local alarms and control system alarms at pre-established set points. Likewise, 10 process alarms initiate local alarms and control system alarms. The limits set for each alarm 11 identify a commitment to action by operations to respond to the alarm. 12 13 Administrative and/or procedural controls are implemented to ensure that all radiation doses are 14 ALARA. Criticality safety controls are implemented administratively to ensure that operations 15 with fissile material will remain safety sub-critical for normal and credible upset conditions. 16 The 137Cs concentration in the slurry feed is limited to maintain personnel dose to ALARA. 17 The fissile material concentration is limited to minimize the potential for a criticality accident. 18 The radionuclide and fissile material analytical results are documented in the process control 19 plan developed for each campaign. Feed containing fissile concentrations above established 20 limits is not processed. 21 22 23 2.4.3 Storage Facilities 24 25 Storage facilities associated with the 242-A Evaporator, but not located within the main process 26 building, are as follows. 27 28
• Feed tank 241-AW-102 – Underground DST for storing 242-A Evaporator feed solutions 29 (not within the scope of this DSA) 30 31
• Diesel fuel storage tank - Underground storage tank for the standby power generator 32 33
• LERF – Interim storage of process condensate before further treatment and discharge 34 (basins not within the scope of this DSA). 35
36 37 2.4.4 Gaseous Effluent Stacks 38 39 The gaseous effluent stacks are described in detail in Section 2.6. 40 41 42
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2.4.5 242-A Evaporator Confinement Features 1 2 The building layout is such that the radioactive waste is contained within two adjacent heavily 3 shielded rooms (i.e., the pump room and evaporator room and into a heavily shielded slurry 4 sampler). Solutions are contained within process piping and equipment within the rooms. 5 Underground-encased transfer lines for conveying the evaporator feed and slurry between the 6 242-A Evaporator and tank farm facilities enter and exit these rooms directly from the building 7 exterior. This arrangement eliminates piping process streams through non-process areas of the 8 facilities. 9 10 Vessel C-A-1 has a working volume of ~26,000 gal and a maximum volume, if filled to the 11 deentrainer pad level, of ~35,600 gal, including the reboiler and associated piping. The floor of 12 the evaporator room and a portion of the floor of the pump room are situated 10 ft. below grade 13 to contain process liquids in the event of a vessel or piping failure. The resulting volume of 14 ~7600 ft3 is sufficient to contain the entire contents of vessel C-A-1 and associated recirculation 15 loop ~4,600 ft3. 16 17 The entire area is served by a bridge crane. Only the load-out and hot-equipment storage room is 18 normally open to the overhead crane gallery. The pump room is provided with removable cover 19 blocks that, in association with the building ventilation system, form a confinement barrier 20 between the pump room and the rest of the canyon area. A roll-up curtain-type door is installed 21 horizontally in the loading room. 22 23 242-A Evaporator feed is the primary source of contamination for the evaporator room, pump 24 room, load-out and hot-equipment storage room, and loading room. This solution contains 25 significant concentrations of radionuclides from a radiation protection standpoint. The principal 26 source of contamination for the condenser room and ion exchange room is the process 27 condensate, which contains relatively low concentrations of radionuclides. For this reason, the 28 building layout physically separates the condenser room and ion exchange room from the other 29 processing areas. The floor of the condenser room is 10 ft. below grade to contain process 30 condensate in the event of a vessel or piping failure. 31 32 Pressure, level, density, and deentrainer pad differential pressure measurement in the C-A-1 33 vessel are performed remotely through the use of the dip tube instrumentation system. A series 34 of ½-in. instrument sensing lines (dip tubes) run between pressure instruments located on the 35 fifth floor of the condenser room and the C-A-1 vessel, at various locations of the vessel. A 36 small airflow from the instrument to the C-A-1 vessel is provided to ensure proper function of 37 the dip tubes and to prevent contamination flow back from the vessel to the instruments. Use of 38 the dip tube system provides a confined method of measuring important system parameters 39 without having to locate pressure instrumentation at the C-A-1 vessel. 40 41 The ventilation system works in concert with the facility floor plan to direct airflow from areas 42 of lesser contamination potential to areas of greater contamination potential. Airlocks separate 43 potentially contaminated areas from non-contaminated areas. 44 45
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Exhaust air passes through a cleanup system consisting of two stages of HEPA filters to ensure 1 that releases meet DOE guidelines established in DOE O 458.1, Radiation Protection of the 2 Public and the Environment, and are as low as reasonably achievable (ALARA). Detailed 3 descriptions of the ventilation systems are provided in Section 2.6. 4 5 6 2.5 PROCESS DESCRIPTION 7 8 This section describes the individual processes in the 242-A Evaporator, and presents process 9 parameters, types and quantities of hazardous materials, process equipment, instrumentation and 10 control systems and equipment, basic flow diagrams, and operational considerations. 11 12 The instrumentation, controls, interlocks, and administrative controls that assist in providing for 13 safe operation and safe shutdown of the 242-A Evaporator are described in Section 2.5.9. 14 Secondary confinement and backup or standby features during normal operations, abnormal 15 operations, and maintenance activities are also described. 16 17 18 2.5.1 Plant Feed 19 20 The 242-A Evaporator receives mixed waste (i.e., waste containing both radioactive and 21 hazardous components) as feed pumped from DSTs. Most of the waste stored in the DSTs was 22 generated by various Hanford Site process operations conducted before 1991, and has been 23 processed through the 242-A Evaporator. Other wastes include the pumpable liquid fraction of 24 the waste stored in underground SSTs as a part of interim stabilization, retrieval waste, 25 ventilation condensate, and laboratory waste. 26 27 Waste to be treated, or candidate waste, is pumped from various DSTs and staged in one or more 28 selected DST(s) for sampling and analysis. If the candidate waste is acceptable for processing it 29 is transferred to feed tank 241-AW-102, which serves as the feed tank for the 242-A Evaporator. 30 Feed tank 241-AW-102 is a 1 x 106 gal underground DST located south of the 242-A Evaporator 31 in the 241-AW Tank Farm. Process control limits are established for each 242-A Evaporator run 32 based on pre-campaign characterization data. 33 34 Waste processing at the 242-A Evaporator requires laboratory characterization to identify the 35 concentration process end point. Lab characterization includes bench-scale evaporation (boil 36 down) of feed samples simulating the 242-A Evaporator boiling point temperature, vacuum, and 37 density. Determining the end point characteristics assists engineering and operations staff in 38 establishing 242-A Evaporator operating parameters. 39 40 The 242-A Evaporator does not treat “high-level” waste to meet the Land Disposal Restrictions 41 of the Resource Conservation and Recovery Act (RCRA) (42 United States Code [U.S.C.] 42 Sections 6901-6992k). High-level waste is the highly radioactive waste material resulting from the 43 reprocessing of spent nuclear fuel, including liquid waste produced directly in reprocessing and any 44 solid material derived from such liquid waste that contains fission products in sufficient 45 concentrations; and other highly radioactive material that is determined, consistent with existing law, 46 to require permanent isolation (DOE 435.1-1, Radioactive Waste Management Manual). 47
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1 2.5.1.1 Feed Physical, Chemical, Radiological Characteristics. The physical, chemical, 2 and radiological characteristics of the 242-A Evaporator feed vary greatly from one campaign to 3 the next. In general, the feed is a highly-alkaline liquid (pH 13) with a specific gravity up to 4 ~1.4. The primary chemical constituents are sodium hydroxide, sodium nitrate, sodium nitrite, 5 sodium carbonate, sodium aluminate, and sodium sulfate. Small quantities of organic chemicals 6 are also present. 7 8 The 242-A Evaporator feed is designated as mixed waste containing trace amounts of organic 9 solvents (primarily non-halogenated, but some halogenated) and heavy metals. It is corrosive; 10 and it might exceed the Washington State criteria for toxicity and persistence based on the 11 known or suspected chemical constituents. Detailed information regarding the waste designation 12 of the feed can be found in the 242-A Evaporator portion of the Hanford Facility Resource 13 Conservation and Recovery Act Permit for the Treatment, Storage, and Disposal of Dangerous 14 Waste (Ecology 2007). 15 16 The principal radionuclides in the feed are 90Sr and 137Cs. Minor concentrations of 3H, 14C, 79Se, 17 99Tc, and other fission products and trace quantities of uranium, 239Pu, and 241Am are also 18 present. 19 20 2.5.1.2 Feed Specifications. Feed specifications are established to: 21 22
• Ensure operating requirements for criticality, exothermic chemical reactions, and other 23 safety and process requirements are not exceeded; 24 25
• Ensure the process condensate meets LERF acceptance limits; and 26 27
• Ensure the waste meets waste acceptance requirements in the 242-A Evaporator portion 28 of the Hanford Site RCRA Permit. (Ecology 2007) 29
30 The feed specifications and the bases associated with each specification are provided in 31 HNF-SD-WM-DQO-014, 242-A Evaporator Data Quality Objectives. 32 33 The 242-A Evaporator portion of the Hanford Site RCRA Permit includes a waste analysis plan 34 that established feed limits on uncontrolled chemical reactions, chemical compatibility, and 35 organic concentrations. The organic concentration limits are established for two purposes: 36 (1) compliance with organic gaseous emission limits in 40 CFR 264, “Standards for Owners and 37 Operators of Hazardous Waste Treatment, Storage, and Disposal Facilities,” Subpart AA; and 38 (2) compliance with LERF waste acceptance criteria related to protecting the basin liner system. 39 The feed concentration is limited to ensure compliance with LERF waste acceptance criteria are 40 described in HNF-SD-WM-DQO-014. 41 42 43
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2.5.2 Plant Products and Byproducts 1 2 Evaporated waste produced at the 242-A Evaporator is called slurry. Slurry is pumped from the 3 242-A Evaporator to the DST system. If the concentration of the waste in one pass through the 4 242-A Evaporator is inadequate, the slurry may be pumped back and concentrated further in a 5 second pass. 6 7 The 242-A Evaporator produces a secondary waste stream, process condensate, which requires 8 further processing before discharge. It is considered a byproduct because it is derived directly 9 from the 242-A Evaporator feed. (Note: this should not be confused with other specialized 10 applications of the term ‘byproduct.’) Process condensate consists primarily of the condensed 11 vapors from the 242-A Evaporator process. It is initially collected and filtered within the 12 242-A Evaporator, then discharged to the LERF for storage prior to treatment at the ETF. The 13 process condensate is designated as a mixed waste (Ecology 2007). 14 15 In addition to the slurry and process condensate products, other effluent streams leaving the 16 242-A Evaporator are monitored for contamination and discharged to the TEDF. These streams 17 include steam condensate (after passing through the reboiler) and used raw water (after passing 18 through the condensers). 19 20 Non-condensable vapors that have passed through the condensers, as well as headspace vapors 21 from the process condensate tank TK-C-100, are discharged through the vessel vent system. 22 Vessel vent vapors and gasses are monitored for ammonia and radionuclide content, filtered, and 23 discharged to the atmosphere. 24 25 2.5.2.1 Product and Byproduct Physical, Chemical, Radiological Characteristics. The 26 physical, chemical, and radiological characteristics of the slurry vary from one 242-A Evaporator 27 campaign to the next. In general, the slurry is a highly alkaline liquid (pH 13) with a specific 28 gravity up to ~1.5. The temperature of the discharged slurry is ~120°F – 130°F (see Table 2-1). 29 30 2.5.2.2 Product and Byproduct Specifications. Slurry produced by the 242-A Evaporator 31 must meet tank farm specifications summarized in HNF-SD-WM-OCD-015, Tank Farms Waste 32 Transfer Compatibility Program, which includes considerations such as corrosion specifications, 33 criticality controls, flammable gas controls, and waste segregation. 34 35 36 2.5.3 General Plant Functions 37 38 The 242-A Evaporator uses a conventional forced-circulation, vacuum evaporator system to 39 concentrate radioactive waste solutions. 40 41
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For a given campaign, it is a batch or continuous process with typical 242-A Evaporator feed, 1 slurry, and process condensate flow rates as follows: 2 3
• Evaporator feed = 70 to 130 gal/min; 4 • Slurry = 30 to 70 gal/min; and 5 • Process condensate = 20 to 60 gal/min. 6
7 The physical, chemical, and radiological characteristics of these streams were discussed in 8 Section 2.5.1 through 2.5.6. 9 10 2.5.3.1 Waste Management. Operating the 242-A Evaporator generates solid, liquid, and 11 gaseous waste streams in addition to the slurry and process condensate. The streams are 12 described in the following sections. 13 14 2.5.3.1.1 Solid Waste. Solid waste consists primarily of used PPE and containment materials, 15 spill cleanup materials, replaced process equipment, office waste, and facility maintenance and 16 janitorial waste. Collecting, packaging, storing, transporting, and disposing of radioactive, 17 mixed, hazardous, and nonradioactive-nonhazardous solid waste is discussed in Chapter 8.0, 18 “Hazardous Material Protection.” All waste handling activities are in accordance with 19 established requirements and procedures. 20 21 2.5.3.1.2 Liquid Waste. The principal liquid waste streams are steam condensate and 22 condenser cooling water. Steam condensate is potentially contaminated. Monitoring and 23 sampling requirements for discharge to TEDF are specified in the TEDF acceptance criteria. 24 The condenser cooling water system is contained and pressurized, so the probability of 25 contamination with radioactive materials is low and only monitoring and record sampling is 26 required. 27 28 2.5.3.1.3 Airborne Waste. The airborne streams are the K1 ventilation system exhaust and the 29 vessel ventilation system exhaust. The K1 ventilation system services contaminated areas of the 30 242-A Building. Provisions are required to maintain confinement pressure differentials within 31 the facility and to ensure that discharges of radioactive materials meet applicable regulations. 32 The K1 ventilation system exhaust stream is HEPA filtered, monitored for the presence of 33 radioactive materials, and sampled to ensure that release limits are met. The vessel ventilation 34 system is the offgas system for the C-A-1 vessel and process condensate tank TK-C-100. The 35 vessel ventilation exhaust stream is HEPA filtered, monitored for the presence of radioactive 36 materials, and sampled to ensure that release limits are met. 37 38 2.5.3.1.4 Transportation. Underground piping is used to transfer process and waste streams 39 and transportation requirements are limited. Provisions are required and in place for periodic 40 delivery of bulk chemical solutions and replacement parts for failed or spent process equipment 41 and for shipping process samples and solid waste. Use of public roadways is not required 42 because all deliveries to and shipments from the 242-A Evaporator are on the Hanford Site. All 43 shipments of hazardous materials are in accordance with the requirements specified in 44 DOE/RL-2001-36, Hanford Sitewide Transportation Safety Document. 45 46
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1 2.5.4 242-A Evaporator Process Operations 2 3 A process control plan is developed by the engineering organization based on results of feed 4 sample analyses from candidate DSTs and desired operating conditions and product 5 characteristics for each campaign. Process control plans are developed, approved, and issued in 6 accordance with TFC-ENG-CHEM-C-11, Process Control Plans. A process control plan is 7 required prior to 242-A Evaporator startup to ensure successful operation, and it includes the 8 following topics. 9 10
• The volumes of feed expected to be processed through the 242-A Evaporator, and, if 11 staging waste from several DSTs, the sequence for transferring into feed tank 12 241-AW-102, including any blending instructions. 13 14
• The waste volume reduction (WVR) target that gives the desired end result for the 15 campaign, and a forecast of the slurry product specific gravity based on laboratory 16 boildown analysis. 17 18
• A forecast of the slurry product volume transferred to the slurry receiver tank and the 19 process condensate byproduct volume transferred to LERF. 20 21
• An analysis of pre-campaign samples taken from each tank, laboratory boildown 22 information, compatibility information (Section 2.5.10.1) and the sampling required 23 during the campaign. 24 25
• A forecast of the final slurry product concentrations, including radionuclides, inorganic 26 compounds, and total organic compounds, based on the predicted WVR. 27
28 The 242-A Evaporator receives a mixed blend feed from feed tank 241-AW-102 consisting of 29 unprocessed and processed wastes and recycled liquids removed from tank farm storage tanks 30 after solids have settled. The feed is pumped into the recirculation line on the upstream side of 31 the reboiler at a rate controlled to maintain a constant C-A-1 vessel liquid level (C-A-1 is 32 initially charged with water because if the evaporative process were to begin with raw feed the 33 initial off-gassing of ammonia would result in additional environmental emission concerns). As 34 the feed enters the recirculation line it blends with the main process slurry stream flowing to the 35 reboiler. 36 37 The mixture is heated in the reboiler to a specified operating temperature, normally 100°F to 38 140°F, by using low-pressure saturated steam at 10 lbf/in2 gauge. A rapid flow of slurry through 39 the reboiler, ∼ 13,000 gal/min, ensures only a slight temperature differential across the reboiler, 40 and minimizes scale formation on the heat transfer surfaces. 41 42 The heated slurry stream is discharged from the reboiler to the C-A-1 vessel, which is maintained 43 at a pressure of 40 to 80 torr for normal evaporation operation. The pressure in the C-A-1 vessel 44 can be lowered to below 40 torr as a method of cooling the C-A-1 contents before dumping the 45 contents back to 241-AW-102. Under this reduced pressure, a fraction of the water in the heated 46
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slurry flashes to steam and is drawn through two wire mesh deentrainer pads into a 42-in. vapor 1 line that leads to the primary condenser. 2 3 After a mean residence time of ~2 min, the liquid flows to the recirculation pump suction from 4 the bottom of the C-A-1 vessel and lower recirculation line. 5 6 The recirculation pump pushes the slurry through the reboiler at high velocities to provide the 7 following: 8 9
• Improve the heat transfer coefficient; 10 • Reduce fouling of heat transfer surfaces; 11 • Keep solids in suspension; and 12 • Permit transfer of large quantities of heat with only a small change in temperature of the 13
solution being heated. 14 15
The static pressure of the solution above the reboiler is sufficient to suppress the boiling point so 16 the solution will not boil in the reboiler tubes. Boiling occurs only near or at the liquid surface in 17 the C-A-1 vessel. 18 19 When the process solution has been concentrated to specified parameters, a small fraction is 20 withdrawn from the upper recirculation line upstream of the feed addition point and is transferred 21 by slurry pump P-B-2 to an underground storage tank in tank farms. At low slurry flow rates the 22 product may be drained by gravity to the designated tank farms tank, or slurry pump P-B-2 can 23 be used to facilitate the transfer. As the liquid cools, some precipitates might form and settle to 24 the bottom of the storage tank. 25 26 Slurry pump P-B-2 is designed for high pressures and volume so the product liquid can be 27 transferred at high velocities and minimize the potential for line plugging due to precipitation of 28 solids. The critical velocity, which is the fluid velocity where solids begin to settle, is calculated 29 based on the predicted solids content of the slurry, and is incorporated into the process control 30 plan. 31 32 Vapors are removed from the C-A-1 vessel by the vacuum eduction system, which consists of 33 two steam eductors and the condensers E-C-1, E-C-2, and E-C-3. Pressure in the CA-1 vessel is 34 maintained by the eduction system. A majority of the vapors and jet steam are condensed in the 35 condensers, which drain to the condensate collection tank. An in-line pump moves the process 36 condensate from the tank through a filter to remove solids and it is discharged to the LERF. 37 Non-condensable gases from the eduction system are filtered and discharged to the atmosphere 38 through the vessel ventilation system. 39 40 The cooling water from the condensers, designated “used raw water,” and steam condensate 41 streams are discharged from the 242-A Building to the TEDF. Sampling and in-line monitoring of 42 these streams is performed in accordance with requirements given in RPP-RPT-59117. The 43 process condensate is discharged to the LERF. Sampling and monitoring of this stream is 44 performed in accordance with the requirements given in Interface Agreement between 242-A and 45 Liquid Effluent Retention Facility; Conversion of HNF-3395 Rev 6. 7//272017 (Foster 2017). 46
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These three streams (process condensate, steam condensate, and cooling water) are provided with 1 grab sampling and radiation monitoring systems. 2 3 The radiation monitor and proportional sampler in the steam condensate system monitors the 4 steam condensate from the reboiler and other steam condensate streams in the condenser room 5 (except drain 395 from the HVAC room and drain SC-505 from the AMU tanks steam jackets). 6 An automatic diversion valve in the steam condensate system diverts the condensate to feed tank 7 241-AW-102 if the radioactive contamination alarm set point is exceeded. The radiation 8 monitoring and diversion system also monitors reboiler condensate before it reaches steam 9 condensate weir box TK-C-103. The steam condensate is analyzed for radionuclides in addition 10 to the analytes identified in RPP-RPT-59117. Increased radionuclide levels, pH, and/or 11 conductivity could indicate a possible leak and the presence of hazardous chemicals. The steam 12 condensate has been designated a non-regulated stream based on previous compliance sampling. 13 14 The condenser cooling water stream is monitored for pH, electrical conductivity, and 15 radioactivity, and is proportionally sampled. It is not equipped with a diversion valve because 16 the potential for radionuclide contamination of this stream is very low and the flow volume is 17 large. If the condensers were to develop a leak, the raw water would leak into the process 18 condensate stream because of the higher raw-water pressure of 100 lbf/in2 gauge. Also, 19 radionuclide concentrations would be extremely low and detectable only by sample analysis due 20 to the high volume of cooling water. A plant shutdown would be required if the cooling water 21 should become contaminated. This design complies with the design criteria outlined in 22 Section 2.3. 23 24 The process condensate system is monitored for radioactivity and proportionally sampled. It can 25 be diverted automatically to either process condensate tank TK-C-100 or to feed tank 26 241-AW-102 to be recycled as 242-A Evaporator feed (Section 2.5.8.5.3). 27 28 The diversion criteria for the process condensate and the steam condensate systems are based on 29 a number of factors including ALARA considerations, environmental release criteria, LERF 30 acceptance criteria, TEDF acceptance criteria, and engineering judgment. 31 32 2.5.4.1 Feed Preparation. Liquid waste from candidate feed tanks are transferred to feed 33 tank 241-AW-102. Candidate feed tanks are DSTs that contain waste selected for processing 34 during a campaign. Feed preparation consists of sampling and transferring waste from the 35 candidate feed tanks to 241-AW-102, and if required, mixing the tank contents. The candidate 36 feed tanks and the estimated volumes are explained in the process control plan. Occasionally the 37 sequence of pumping feed into the feed tank will specify blending wastes containing high 38 concentrations of certain analytes, such as ammonia, with wastes containing low concentrations. 39 The feed and slurry stream waste characteristics are evaluated against the requirements identified 40 in chapters 3.0 and 5.0 and the technical safety requirements to ensure that the feed is acceptable 41 before the contents of the campaign tanks are transferred to the 242-A Evaporator. 42 43 A surface sample of each candidate feed tank is taken for visual inspection and analytical tests 44 are performed to check for separable organics. These samples are taken when there is inadequate 45 surface sample data prior to a campaign. If a separable organic layer is observed, an operating 46
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specification limits the lower liquid level in feed tank 241-AW-102 (HNF-SD-WM-DQO-014). 1 This limit is a control designed to prevent pumping separable organics into the 242-A 2 Evaporator. 3 4 Wastes containing high ammonia concentrations can be mixed in feed tank 241-AW-102 with 5 wastes of low ammonia concentration to reduce the rate of ammonia release in the process 6 condensate and vessel vent system. The available mixing methods are: (1) recirculate feed back 7 into feed tank 241-AW-102 using the feed pump, and (2) mix the tank contents using the air-lift 8 circulators. 9 10 The feed pump can be valved to recirculate directly to feed tank 241-AW-102 instead of into the 11 242-A Building. The feed is continuously recirculated to control rate of feed to the 12 242-A Evaporator during normal operation. Recirculating the feed provides some mixing in feed 13 tank 241-AW-102, but it is only partially successful. 14 15 Feed tank 241-AW-102 has two air-lift circulators, 24 in. and 16 in. in diameter that can be used 16 for mixing the tank contents. The liquid must be above the minimum tank level for proper 17 circulator operation. This equipment belongs to and is operated and maintained by tank farms. 18 19 Blending of the feed tank contents and qualifying other tanks for a 242-A Evaporator campaign 20 is determined by sampling the tanks. The sampling protocols and analytical results are used to 21 determine if and how the tanks will be processed in the campaign. 22 23 The effect of marginal mixing in the feed tank is that periodic adjustments of the feed rate and 24 the product flow rate might be required because the feed composition changes as the liquid level 25 in the feed tank drops and different feed concentrations are pumped into the 242-A Evaporator. 26 The 242-A Evaporator design, campaign tank sampling plan, process control plan, and operating 27 procedures take these factors into account and allow these wastes to be processed and 28 concentrated, although the feed concentration can vary. 29 30 2.5.4.2 Waste Volume Reduction. The waste volume reduction factor (WVRF) refers to the 31 fraction of water volume removed from the feed flow. The 242-A Evaporator process is 32 designed to reduce the volume of waste stored in waste tanks through WVR of dilute waste. The 33 242-A Evaporator process appears to operate most efficiently when the WVRF is ~25% – 50%. 34 A 50% WVRF, for example, is achieved when the feed rate is 90 gal/min and the slurry rate is 35 45 gal/min. The WVRF values are monitored carefully during processing. The two primary 36 methods for determining the WVRF values are (1) flow rates of the feed stream and slurry 37 stream, and (2) level loss in the feed tank versus level gained in the slurry receiver tank. 38 39 Higher WVRF values mean that the slurry flow is low in comparison to the feed rate. If the 40 slurry flow rate drops below the low flow alarm setpoint specified in the process control plan or 41 process memo, the low slurry flow alarm is activated. This causes the slurry flow control valve 42 to close and an automatic flush of the slurry pipeline occurs. The low flow interlock can be 43 bypassed by placing the flow control valve in manual when very dilute wastes, i.e., suspended 44 solids < 5%, are processed. 45 46
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The objective of the 242-A Evaporator is to concentrate the waste to the target concentration. 1 The process control plan provided by the engineering organization specifies the process 2 conditions (e.g., density, temperature, and pressure) that direct operations personnel in obtaining 3 the target concentration. 4 5 2.5.4.3 Decontamination of Offgas and Process Condensate. The 242-A Evaporator 6 process is designed to contain and confine radioactive and hazardous material entering in the 7 feed stream and within the product slurry flow. The offgas flow from the C-A-1 vessel passes 8 through two de-entrainment pads, which are flushed continuously with water in alternate quarter 9 sections, to remove as much of the entrained contamination as possible and keep it within the 10 vessel. Stack offgases pass through two HEPA filters mounted in series to minimize 11 radioactivity in the gaseous effluent stream. 12 13 Decontamination of process systems is occasionally necessary to reduce radiation doses to the 14 operators and maintenance personnel to ALARA (Section 2.5.8.7). 15 16 2.5.4.4 Interfaces Between Systems. The primary interfaces between systems within the 17 242-A Evaporator process are the controls and interlocks. Many of these are hardwired into the 18 control system to ensure safe shutdown. Many of the interlocks are process and ALARA safety 19 related. A complete discussion of the controls and interlocks is in Section 2.5.9. 20 21 22 2.5.5 Process Flow Diagram for 242-A Evaporator Operation 23 24 A process flow diagram is shown in Figure 2-6. This figure provides a depiction of the process 25 and effluent streams. The MCS displays the 242-A Evaporator processes on the monitor screens, 26 which show a schematic flow diagram with instruments and process values. 27 28 29 2.5.6 Process Chemistry and Physical Chemical Principles 30 31 This section describes the chemical and physical principles that apply to the 242-A Evaporator 32 process. 33 34 2.5.6.1 Evaporative Concentration. Feed solutions are concentrated in the C-A-1 vessel, 35 which is maintained at a pressure of ~40 to 80 torr during normal operation. The pressure in the 36 C-A-1 vessel can be lowered below 40 torr as a method of cooling the C-A-1 contents before 37 dumping the contents back to 241-AW-102. Under this reduced pressure, a fraction of the water 38 in the salt slurry concentrate flashes to steam and is drawn through two wire mesh deentrainer 39 pads into the 42-in. vapor line leading to primary condenser E-C-1. Boiling occurs only at or 40 near the liquid surface of the vessel. The static pressure of the solution above the reboiler 41 prevents boiling in the reboiler tubes. 42 43 As evaporation occurs, supersaturation of the dissolved salts increases. It is relieved by growth 44 on existing crystals and generation of new salt crystal nuclei in the slurry liquid. The 45 242-A Evaporator feed is blended with ~180 L of slurry per liter of feed in the recirculation loop 46
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before entering the reboiler. In the C-A-1 vessel, ~0.003 L of water per liter of recirculated 1 slurry is evaporated. Therefore, instantaneous concentration changes during waste evaporation 2 are small because of the large flow rate and the slurry inventory in the 242-A Evaporator. 3 Supersaturation is minimized, which promotes deposition of precipitated solids on existing 4 particles as opposed to nucleation of new particles or deposition on vessel surfaces. 5 6 The water vapor leaving the liquid surface in the C-A-1 vessel is superheated ~5°F because of 7 the boiling point elevation of the terminal liquid. This superheat is relieved by evaporation of 8 the continuous water spray on the upper deentrainer pad. 9 10 When the product slurry has been concentrated to the desired amount, a small fraction is 11 withdrawn from the upper recirculation line and transferred by gravity or the slurry pump to an 12 underground storage tank. The concentration of solids in the slurry is limited to less than 13 30 vol% to prevent plugging the slurry transfer lines. The slurry then settles in the storage tank 14 into a saltcake layer and a supernatant liquid layer. 15 16 2.5.6.1.1 Feed Compositions. The feed for the 242-A Evaporator consists of liquid waste from 17 retrieval or other tank farm operations. The largest portion of these wastes consists of dilute 18 nonradioactive aqueous salts. Feed concentrations vary depending on the waste source, the 19 degree to which the waste has been concentrated previously in the 242-A Evaporator, and 20 blending with other feeds. 21 22 Ammonia in the 242-A Evaporator feed is controlled to prevent release of ammonia gas from the 23 vessel ventilation system in excess of the Comprehensive Environmental Response, 24 Compensation and Liability Act of 1980 (CERCLA) limit of 100 lb per 24-hr period. When high 25 ammonia concentration feeds are being processed, approximately 90% of the ammonia in the 26 feed is converted to ammonia gas, with the remaining 10% exiting in the slurry product. The 27 majority of the ammonia gas is then condensed in the E-C-1 primary condenser and leaves the 28 242-A Evaporator in the process condensate stream. Approximately 5% of the ammonia in the 29 feed is not condensed and is discharged through the vessel ventilation stack 30 (WHC-SD-WM-PE-054, 242-A Campaign 94-2 Post Run Document). Current practice is to 31 control ammonia concentration in the feed if necessary, which limits the amount of ammonia 32 released in the vessel ventilation stream. 33 34 The principal radionuclides in the 242-A Evaporator feed are the fission products 137Cs and 90Sr. 35 The concentrations of radionuclides vary in the feed for the same reasons given above for the 36 nonradioactive aqueous salts. 37 38 The typical specific gravity of feed solutions is shown in Table 2-1. 39 40 2.5.6.1.2 Slurry Compositions. The intermediate products produced by the 242-A Evaporator 41 slurry concentrations are projected from feed concentrations and WVR for non-volatiles. Solids 42 production in DSTs is established from laboratory boil-down studies. 43 44 The typical specific gravity of slurry product is shown in Table 2-1. 45 46
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1 2.5.7 Ion Exchange 2 3 The ion exchange columns are no longer used and were removed from the facility in 2003. 4 5 6 2.5.8 Mechanical Process Systems 7 8 The process systems discussed in this section are the evaporation system and the vapor 9 condensation and treatment system. These systems are shown on Figure 2-6, which shows the 10 location of the effluent sampling systems for the process. Not shown is the source of solid waste 11 generated in the 242-A Evaporator. Chemical systems are also discussed. 12 13 2.5.8.1 Evaporation System. The evaporation system includes the E-A-1 reboiler, C-A-1 14 vessel, recirculation pump P-B-1, slurry pump P-B-2, and all associated equipment, 15 instrumentation, utilities, and piping. The system accepts feed from the feed tank, concentrates 16 the feed tank solution, pumps the concentrate (slurry) to the slurry tank, and filters C-A-1 vessel 17 offgas flow. 18 19 A complete description of the materials of construction, pressure and temperature limits, and 20 dimensions are found in the construction specifications (Vitro 1974, Construction Specification 21 for 242-A Evaporator-Crystallizer Facilities, Project B-100). The materials listed are for 22 historical purposes only. Modifications performed after the original construction are in 23 accordance with applicable code requirements. 24 25 Corrosion allowances for equipment in the 242-A Evaporator system are ≤ 25 μm/yr 26 (0.001 in./yr) unless specified otherwise on the individual equipment drawings. 27 28 The 242-A Evaporator is a conventional forced-circulation vacuum vessel designed to 29 concentrate low-temperature waste containing relatively small quantities of fission products. 30 The low-temperature waste is pumped from feed tank 241-AW-102 into the recirculation line of 31 the C-A-1 vessel. The feed is injected into the slurry being recirculated. The waste passes 32 through the E-A-1 reboiler tubes and is heated slightly by low-pressure steam condensing in the 33 shell side of the heat exchanger. The heated waste is discharged at the liquid/vapor interface of 34 the C-A-1 vessel liquid level with waste vapor generated at the surface of the liquid and passing 35 up through two deentrainer pads in the vessel. Counter-current filtered raw water or recycled 36 process condensate flows down through the deentrainer pads decontaminating the upward 37 flowing vapors. The majority of the liquid in the C-A-1 vessel circulates downward through the 38 vessel to be recirculated by recirculation pump P-B-1. 39 40 A small fraction of the recirculated flow is withdrawn from the recirculation pipe line and 41 transferred to the underground slurry receiver storage tank. 42 43 The following paragraphs describe the major components of the evaporation system, the 44 interrelationship of the individual components, and the means by which these components are 45 combined within the system. A physical description of each major component including 46
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dimensions, design and operating temperatures and pressures, materials of construction, special 1 design features, and process limitations are provided. 2 3 2.5.8.1.1 Reboiler (E-A-1). Process slurry is heated in the E-A-1 reboiler (Figure 2-13) before 4 the slurry enters the C-A-1 vessel. A 28-in. diameter stainless steel pipeline connects the 5 reboiler with the recirculation pump P-B-1 discharge flange and with the C-A-1 vessel at a 6 midpoint on the side of the vessel. Two pressure-indicating probes, PE-EA1-2 and PE-EA1-12, 7 monitor slurry differential pressure across the reboiler. These instruments are used to monitor 8 reboiler operation and to assist in detecting reboiler tube plugging. Temperature elements 9 TE-EA1-7 and TE-EA1-1 provide temperature differential indication for the reboiler. 10 11 Steam condensate from the reboiler flows to the condenser room via a 4-in. diameter drain line 12 and discharges just before condensate enters the steam condensate weir box TK-C-103. 13 A portion of the steam condensate is pumped from the weir through a proportional 14 sampler/radiation monitor, RC-1, and returned to the weir. If the radiation monitor detects 15 radiation above the instrument alarm setpoint, the steam condensate is automatically diverted to 16 feed tank 241-AW-102. Normally, the steam condensate discharged from steam condensate weir 17 box TK-C-103 is routed to TEDF. 18 19 The 2.5 x 107 Btu/h duty reboiler is a vertical tube unit that has steam on the shell side and 20 process solution on the tube side. Standard operating parameters of the waste (tube side) are 21 40 to 80 torr (absolute) pressure and 115 to 140°F temperature. The reboiler consists of 22 364 tubes, each having a 14 ft-1/8 in. length and a 1.5 in. outside diameter (OD), arranged with a 23 1-7/8 in. triangular pitch. The tubes are encased by a 40.5 in. OD, 457 cm 15-ft long stainless 24 steel shell. Temperature elements TE-EA1-7 and TE-EA1-1 are located at the reboiler slurry 25 inlet and outlet, respectively, to measure the waste differential temperature across the reboiler. 26 Pressure elements PE-EA1-2 and PE-EA1-12, located at the inlet and outlet of E-A-1 reboiler, 27 respectively, monitor the reboiler differential pressure. The reboiler has three equally spaced 28 baffles, as well as an impingement baffle at the steam inlet to distribute steam vapor evenly. The 29 total heat transfer surface area is 2,000 ft2. 30 31 Steam at a pressure of 10 lbf/in2 gauge is supplied to the reboiler shell side by a 16-in. diameter 32 feed line. When steam is isolated from the reboiler, solenoid valve HV-EA1-3 is open and 33 18 psig air is provided to the reboiler shell. When process activities are ongoing, and steam is 34 supplied to the reboiler, solenoid valve HV-EA1-3 closes to isolate the air to the reboiler. Two 35 vacuum breakers PSV-1 and PSV-2, connected to the steam feed line prevent vacuum from 36 forming in the event of a steam column collapse. 37 38 2.5.8.1.2 Evaporator Vessel (C-A-1). Process solution from the reboiler discharges to the 39 C-A-1 vessel via the upper recirculation line. The 242-A Evaporator consists of two sections, 40 the lower section containing the slurry being circulated and the upper vapor-liquid separation 41 section, which contains deentrainer pads and deentrainer sprays. Vapor flows out of the 42 separator through a 42-in. stainless steel vapor line at the top and concentrated slurry exits via a 43 28-in. stainless steel recirculation line at the bottom. 44 45
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The lower (liquid) section is a 14-ft diameter stainless steel shell with a 22,500 to 26,000 gal 1 normal operating capacity (including the recirculation loop and reboiler). 2 3 The upper (vapor) section is an 11 ft-7 in. diameter stainless steel shell. The total volume of 4 the C-A-1 vessel, if filled to the top of the vapor section, is 35,600 gal. The top section of the 5 C-A-1 vessel contains two deentrainer pads ~3 ft-4.5 in. apart. The pads remove liquids and 6 solids to prevent carryover into the vapor header. The lower pad is 4 in. thick, and the upper pad 7 is 6 in. thick; both are T-304 stainless steel 0.011-in. wire mesh packed to a density of 12 lb/ft3. 8 9 Sixteen spray nozzles, four on the top and four on the bottom of each pad, are spaced equally and 10 operated alternately to distribute water to the pads evenly. The top sprays to the upper pad are 11 normally controlled automatically for sequential operation for 15 seconds. Both sets of sprays to 12 the bottom pad are on a distribution ring and are controlled manually. Separate manual controls 13 and a distribution header are provided for another set of sprays that permit the sides of the 14 242-A Evaporator below the lower de-entrainment pad to be sprayed to prevent caking. Four 15 other nozzles located below the lower de-entrainment pad serve to spray down the side of the 16 vessel with water at the end of the campaign. These nozzles are shared with the vessel purge air 17 system (Section 2.5.9.2.1.2). This system is no longer in use. One nozzle on the East end of the 18 C-A-1 vessel has been removed to allow unimpeded purge air flow into the vessel. 19 20 The C-A-1 vessel is equipped with a 6-in. diameter drop-out drain line that runs from the 28-in. 21 recirculation loop, along the evaporator room floor, through a penetration in the north wall, and 22 out to feed tank 241-AW-102. This line drains the C-A-1 vessel contents back to feed tank 23 241-AW-102 via encased drain line DR-335 under six conditions: (1) at the end of a campaign 24 when slurry can no longer be pumped by slurry pump P-B-2; (2) upon loss of recirculation pump 25 P-B-1 (which initiates an automatic shutdown of the 242-A Evaporator process); (3) an 26 operator-initiated emergency shutdown of the 242-A Evaporator process; (4) a seismic event in 27 which the facility emergency stop button is activated; (5) flammable gas conditions of high 28 temperature or loss of vacuum without purge air are detected (safety interlock #S2); or (6) high 29 level or waste boil-over conditions are detected (safety interlock #S1). The drop-out line ties 30 into the 28-in. recirculation line at dump valve HV-CA1-7 and contains an inline dump valve, 31 HV-CA1-9. A 2-in. raw water flush line ties in to the drop-out line between these two valves. 32 33 242-A Evaporator instruments monitor the following parameters: 34 35
• Temperature; 36 • Pressure; 37 • Weight factor (WF) (i.e., liquid level and density); 38 • Flow indication (via coriolis instrument); 39 • Density (via coriolis instrument); and 40 • Differential pressure across the upper and lower de-entrainment pad. 41
42 Both the reboiler and C-A-1 vessel, as well as the recirculation loop, are insulated. 43 The insulation is comprised of a 2-in. thick fiberglass blanket encapsulated in a silicon-coated, 44 woven fiberglass fabric jacket with a silicone foam backing. This insulation originally was 45 designed to permit higher operating temperatures for producing double-shell slurry (DSS). 46
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Because there are no plans to produce DSS, the insulation serves to reduce the quantity of steam 1 the process requires. 2 3 Temperature excursions and pressurization of the vessel are highly unlikely. The low-pressure 4 steam supplied to the reboiler, 10 lbf/in2 gauge, does not supply sufficient heat to cause a rapid 5 temperature increase in the liquid, however moderate temperature excursions of approximately 6 20°F in 20 minutes are still possible. In addition, any increase in pressure caused by a 7 temperature increase is relieved through the 42-in. vapor line. 8 9 The feed line from feed tank 241-AW-102 and the slurry line to underground storage tanks are 10 connected to the 28-in. recirculation line. Slurry can be discharged from the vessel through a 11 separate drain, DR-335, to feed tank 241-AW-102 in case of an emergency. In addition, if the 12 valves on the drain line should fail to operate or if the drain line to the tank is plugged, an 13 emergency method of discharging the slurry is provided by a 4-in. nozzle (nozzle E) on the 14 bottom of the recirculation line. A connector head can be removed from it remotely, discharging 15 the contents of the system to the pump room floor. The pump room sump overflows to the feed 16 tank 241-AW-102. 17 18 The C-A-1 vessel and the recirculation loop have provisions for flushing residual solids from the 19 system and for reducing radiation levels. Water can be added from the raw water supply via the 20 slurry product line flush system, the deentrainer spray and vessel spray system, and the dump 21 line. The drain line to the feed tank, the slurry line to the slurry receiver tank, and the dump line 22 to the feed tank can also be flushed with hot water during the deep flush at the end of the 23 campaign. The deep flush involves boiling water in the C-A-1 vessel after waste was emptied 24 from the vessel, and draining the hot water down the feed line, the slurry line, and the dump line. 25 26 2.5.8.1.3 Recirculation Pump (P-B-1). The stainless steel recirculation pump discharges slurry 27 back to the reboiler via the upper recirculation line. The 28-in. axial flow pump is driven by an 28 electric vertical induction motor and has a 13,000 gal/min output with a 10.85 ft total dynamic 29 head. It is designed to handle slurry containing up to 30% solids by volume and a slurry specific 30 gravity of 1.8. The pump is equipped with a mechanical seal using filtered raw water or process 31 condensate as a barrier fluid. The barrier fluid pressure and flow to the pump seal are monitored. 32 33 2.5.8.1.4 Slurry Pump (P-B-2). Slurry pump P-B-2 is constructed of 304L stainless steel. It 34 pumps concentrated slurry from the recirculation line to the slurry receiver tank. It is a 35 single-stage horizontal centrifugal pump driven by a variable-speed motor with a 32 to 36 110 gal/min normal flow. Slurry pump P-B-2 is equipped with a mechanical seal using filtered 37 raw water or process condensate as a barrier fluid. The barrier fluid pressure and flow to the 38 pump seal are monitored. 39 40 Slurry pump P-B-2 is an electrical motor driven centrifugal pump with a variable frequency drive 41 (VFD) (see RPP-CALC-23897, VFD Driven Induction Motor/Pump Performance Evaluation) 42 and its performance depends on the VFD output. Slurry pump P-B-2 performance is addressed 43 in RPP-15810, Enveloping Tank Farm Transfer Pump Power, Discharge Head, and Flow. 44
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The maximum discharge pressure for slurry pump P-B-2 is limited by a pressure relief valve 1 (PSV-PB2-1) on the pump discharge line. The set pressure is < 244 lb/in2 gauge for the pressure 2 relief valve. 3 4 2.5.8.1.5 Seal Water and Booster Pumps. Both the recirculation pump and the slurry pump 5 are equipped with a dual shaft seal with high-pressure water introduced between the seals to 6 prevent process solution from leaking out of the system. Because the water pressure is 7 maintained at a value in excess of the process pressure at the seal, water can leak into the system 8 or out of the pump along the drive shaft, but the process solution cannot leak out of the pump if 9 the required water pressure is maintained between the seals. The seal water flow cools the seals 10 to prevent overheating. 11 12 Filtered raw water from the 1.5-in. line passes through a filter before reaching booster pumps 13 P-C-105 and P-C-105a. These pumps, which are in parallel, then increase the pressure to ensure 14 recirculation pump P-B-1 and slurry pump P-B-2 have adequate seal water pressure and flow. 15 16 Process condensate supplied from process condensate tank TK-C-100 can be used for seal water 17 for recirculation pump P-B-1 and slurry pump P-B-2. A 2-in. line from nozzle K on process 18 condensate tank TK-C-100 supplies process condensate to condensate recycle pump P-C106. 19 From condensate recycle pump P-C106 the line branches to supply filters F-C-4 and F-C-5, 20 which filter the process condensate prior to HV-CA1-10, which ties the recycle system into the 21 seal water system. 22 23 2.5.8.1.6 Reserved for Future Use. 24 25 2.5.8.1.7 Slurry Flowmeter (FE-CA1-4). Slurry transfer to the slurry receiver tank is 26 monitored with a magnetic flowmeter (FE-CA1-4). A decrease in flow below the set-point value 27 will shut down the pump automatically and initiate a line flush with water. 28 29 2.5.8.1.8 Miscellaneous Equipment. Other equipment includes expansion bellows in the 30 42-in. vapor line and three dip tube assemblies in the vessel. Two assemblies contain the dip 31 tubes that measure the CA1-1 and CA1-2 WF and specific gravity. The other assembly (CA1-3) 32 measures WF only. All dip tubes are 0.5-in. schedule 40 stainless steel. Temperature 33 elements TE-CA1-6 and TE-CA1-6S also are located in the vessel. 34 35 Process jumpers route 242-A Evaporator feed, process slurry, and slurry solutions within the 36 facility to external valve pits. Additional jumpers route electrical power, instrument signals, 37 process and instrument air, steam, water, and grease to various components. Pump room jumper 38 arrangements are shown in Figure 2-14. 39 40 2.5.8.1.9 Slurry Line Flush Capability. The slurry transfer line can be flushed in either 41 direction using manual controls. Flushing involves positioning valves HV-CA1-2 and 42 HV-CA1-2A for the operation, either to the 242-A Evaporator or to the tank farm, and flushing 43 with water. 44 45
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Under certain conditions, tank farms may require that transfer lines be flushed using inhibited 1 water, for corrosion prevention. Inhibited water consists of water treated with hydroxide and/or 2 nitrite. Inhibited water is provided by the water remaining in the C-A-1 vessel at the end of the 3 deep flush activity. Process engineering has determined that there is enough hydroxide and/or 4 nitrite remaining (from the waste) at the end of the deep flush to provide inhibited water to the 5 slurry line. 6 7 2.5.8.1.10 242-A Evaporator System Operating Limits. System operating limits and 8 interlocks are discussed in Section 2.5.9.9. 9 10 2.5.8.2 Vapor Condensation and Treatment. Vapors enter the primary condenser through 11 an overhead 42 in. line. The vapors are drawn into the condenser by the two-stage steam 12 vacuum system and condense in condensers E-C-1, E-C-2, or E-C-3. Two steam eductors, 13 located between E-C-1 and E-C-2 and between E-C-2 and E-C-3, create the vacuum that draws 14 process vapor from the C-A-1 vessel and into the condenser system. Condensate from primary 15 condenser E-C-1 drains to a 20 in. hot well and from there to the process condensate tank 16 TK-C-100 via a 4 in. line. Condensate from E-C-2 and E-C-3 drain directly to process 17 condensate tank TK-C-100 through separate1-in. lines. The remaining uncondensed vapors exit 18 from the E-C-3 condenser via a 3 in. line and are discharged into the vessel vent treatment 19 system. The process condensate collected in process condensate tank TK-C-100 is pumped 20 through filters. Under normal operation, process condensate is pumped to the LERF basins. The 21 process condensate is diverted back to process condensate tank TK-C-100 or feed tank 22 241-AW-102 by valve HV-RC3-3 if the RC-3 radiation monitor setpoint is exceeded. 23 24 The vacuum condenser system has the following components, all of which are located at the 25 40 ft-6 in. (fourth floor) level: 26 27
32 The primary condenser and associated piping is equipped with instrumentation to monitor the 33 following process parameters: 34 35
• Vapor temperature in (TI-CA1-9) 36 37
• Vapor temperature out (TI-EC1-3 for the first condenser, TI-EC2-3 after the second 38 condenser, and TI-EC3-3 after the final condenser) 39 40
• Condensate temperature (TIC-EC1-2) 41 42
• Raw water temperature (TI-EC1-4) 43 44
• Used raw water temperature (TI-EC1-1) 45 46
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• Vapor pressure out (PI-EC3-2) 1 2
• Used raw water radiation (RI-RC2-1) 3 4
• Raw water pressure (PI-RW-1) 5 6
• Used raw water pressure (PI-EC1-9) 7 8
• Used raw water flow (FIC-EC1-1). 9 10 Used raw water passes a radiation monitoring and sampling system that consists of a sampler, 11 sample receiver, and radiation monitor, and is located at the 10 ft-6 in. level. 12 13 The following paragraphs describe the major components of the vapor condensation and 14 treatment system, the interrelationship of the individual components, and the means by which 15 these components are combined within the system. A physical description of each major 16 component including dimensions, design and operating temperatures and pressures, materials of 17 construction, special design features, and process limitations is also included. 18 19 2.5.8.2.1 Primary Condenser (E-C-1). The primary condenser, E-C-1, is a four-pass, 20 tube-in-shell, raw water-cooled condenser with a design heat duty of 2.2 x 107 Btu/h. The shell 21 is ~17 ft-6 in. long and has an inside diameter (ID) of 85 in. It contains 2,950 tubes through 22 which raw water passes at a maximum rate of 3,500 gal/min. The tubes are 11 ft long with a 23 0.75 in. OD. A 4 ft-6 in. impingement plate is located at the vapor inlet; five baffles evenly 24 spaced through the length of the condenser, and two baffles acting as a shroud over the vapor 25 outlets. 26 27 The used raw water flow from primary condenser E-C-1 is joined by the E-C-3 used raw water 28 flow and becomes one of three liquid effluent streams from the 242-A Evaporator. A small 29 portion of the used raw cooling water is routed through the RC-2 radiation monitor, pH and 30 conductivity meters, and proportional sampler as the stream exits to the 200 Area TEDF Pump 31 Station 3. Should this stream become contaminated, a facility shutdown would be required 32 because the cooling water cannot be diverted. 33 34 Steam jet ejector J-EC1-1 maintains a vacuum on the primary condenser that in turn creates a 35 vacuum in the C-A-1 vessel. The ejector consists of a steam nozzle that discharges a 36 high-velocity jet across a suction chamber. Vapors from the primary condenser are entrained by 37 the steam and carried into a venturi-shaped diffuser that converts the velocity energy of steam 38 into pressure energy. Steam is supplied via a 3 in. 90 lbf/in2 gauge steam line, reduced to 1.5 in. 39 before entering the jet, and discharged to the inter-condenser via a 10 in. line. 40 41 2.5.8.2.2 Inter-Condenser (E-C-2). The 242-A Evaporator pressure is maintained by a 42 two-stage jet process. The first stage maintains a vacuum on the primary condenser and consists 43 of a steam jet, an air bleed-in valve, and the inter-condenser. Steam pressure is controlled by a 44 pressure control valve, and the desired vacuum is controlled by bleeding ambient air into the 45 system through air intake filter F-C-2. The air bleed-in valve is controlled by a 46
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pressure-indicator controller that receives its signal from the WF reference pressure tap in the 1 C-A-1 vessel. Vapor discharged from the steam jet contacts the cooling tubes in the 2 inter-condenser and the condensate drains to the condensate collection tank. Uncondensed 3 vapors and used cooling water are routed through separate pipes to the after condenser. 4 5 The inter-condenser is a four-pass, tube-in-shell, raw water-cooled condenser with a design heat 6 duty of 1 x 106 Btu/h. The shell is ~7 ft-3 in. long and has a 15.4 in. ID. It contains 144 tubes 7 through which raw water passes at a rate of 150 gal/min. The tubes are 66 in. long with a 8 0.75 in. OD. 9 10 Uncondensed vapors from the primary condenser enter the inter-condenser, E-C-2, via a 10 in. 11 discharge line from steam jet ejector J-EC1-1. A 1-in. line drains condensed vapors and 12 condensed steam from the steam jet to the condensate collection tank. Uncondensed vapors exit 13 via a 2.5 in. vacuum line to steam jet ejector J-EC2-1. Cooling water enters the inter-condenser 14 through a 3 in. raw water line and exits via a 3-in. line to the after-condenser. 15 16 The inter-condenser and associated piping are equipped with instrumentation to monitor the 17 following process parameters: 18 19
• Vapor temperature out (TI-EC2-3) 20 • Condensate temperature (TI-EC2-2) 21 • Raw water temperature out (TI-EC2-1) 22 • Vapor pressure out (PI-EC2-1, local gauge only). 23
24 2.5.8.2.3 After Condenser (E-C-3). Vapor discharged from the inter-condenser enters the 25 second stage of the vacuum system. This stage consists of another steam jet and the after 26 condenser. Steam pressure is again controlled and the discharged vapor contacts cooling tubes in 27 the after condenser. Condensate is routed to process condensate tank TK-C-100 while the 28 uncondensed vapors are filtered and discharged to the atmosphere through the vessel vent 29 system. Cooling water for this condenser comes from the inter-condenser. The used water 30 exiting from E-C-3 combines with the used raw water from the primary condenser and drains to 31 the 200 Area TEDF Pump Station 3. A small amount of the combined used cooling water is 32 routed through the RC-2 sampler and monitor before draining to the pump station. 33 34 The after-condenser, E-C-3, is a two-pass, tube-in-shell, raw water-cooled condenser with a 35 design heat duty of 7 x 105 Btu/h. The shell is ~7 ft-5 in. long and has an ID of 8 in. It contains 36 45 tubes through which raw water passes at a rate of ~150 gal/min. The tubes are 72 in. long 37 with a 0.75 in. OD. 38 39 Vapor discharged from the inter-condenser enters the second stage of the vacuum system. This 40 stage consists of another steam jet ejector and the after condenser, E-C-3. Steam pressure is 41 provided at 90 lbf/in2 and discharged vapor contacts cooling tubes in the after condenser. 42 Condensate is routed to process condensate tank TK-C-100, while the uncondensed vapors are 43 filtered and discharged to the atmosphere through the vessel ventilation system. 44 45
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Uncondensed vapors from the inter-condenser enter the after-condenser via a 4-in. discharge line 1 from steam jet ejector J-EC1-2. A 1-in. line drains condensed vapors and condensed steam from 2 the steam jet to the process condensate tank TK-C-100. Uncondensed vapors exit via a 3 in. line 3 to the vessel vent system. Cooling water to the after condenser is fed via a 3 in. line from the 4 inter-condenser and exits via a 3 in. line to the used raw water system. 5 6 Steam jet ejector J-EC2-1 maintains a vacuum on the inter-condenser to draw uncondensed 7 vapors to the after condenser. Steam is supplied via a 3 in., 90 lbf/in2 steam line, reduced to 8 1.0 in. before entering the jet, and discharged to the after condenser via a 4 in. line. Before 9 entering the jet ejectors, condensate is removed from the steam by a baffle-type steam separator, 10 SS-C-1, with a maximum capacity of 2,000 lb/h. Condensate from the steam separator drains to 11 steam condensate weir box TK-C-103 for transfer to the 200 Area TEDF. 12 13 The after condenser and associated piping are equipped with instrumentation to monitor the 14 following process parameters: 15 16
• Condensate temperature (TI-EC3-3) 17 • Used raw water temperature (TI-EC3-1) 18 • Vapor pressure out of after condenser (PI-EC3-1, local gauge only) 19 • Used raw water flow rate (FIC-EC3-1). 20
21 2.5.8.3 Process Condensate System. The process condensate system (Figure 2-15) is 22 comprised of the following principal components: 23 24
• Process condensate tank, TK-C-100 25 • Process condensate pump, P-C-100 26 • Process condensate recycle pump, P-C–106 27 • Process condensate filter F-C-1 28 • Process condensate filter F-C-3 29 • Condensate recycle filters, F-C-4 and F-C-5 30 • Radiation monitoring, sampling, and diversion system, RC-3. 31
32 2.5.8.3.1 Reserved for Future Use. 33 34 2.5.8.3.2 Process Condensate Tank (TK-C-100). Process condensate from the primary, inter-, 35 and after-condensers drain by gravity to the process condensate tank TK-C-100, located at 36 the -10 ft level. The tank also receives potentially contaminated drainage from the vessel vent 37 system via a 27 gal. seal pot. The process condensate tank, constructed of stainless steel, is 14 ft. 38 in diameter and 19 ft. high, with a volume of 17,800 gal. The tank is equipped with an agitator, 39 WF, temperature instruments, and has overflow and drain lines to the feed tank. A spray nozzle 40 from the decontamination tank is provided for flushing the tank. A 4-in. line vents the tank to 41 the vessel vent system and a 2-in. steam vent line (Line V-1209) connects to flow measurement 42 tank TK-C-103. Since no valves are installed on the steam vent line, barometric breathing is 43 always assured in the condensate tank and excessive buildup of flammable gases is prevented in 44 both the TK-C-100 and TK-C-103 tanks. 45 46
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2.5.8.3.3 Process Condensate Pump (P-C-100). Process condensate is pumped from process 1 condensate tank TK-C-100 directly to the F-C-1 filter by process condensate pump P-C-100. 2 The pump is located at the -10 ft. level and has a normal operating capacity of 60 gal/min. 3 4 2.5.8.3.4 Process Condensate Recycle Pump (P-C–106). The process condensate recycle 5 system uses process condensate for the lower and upper deentrainer sprays and as seal water for 6 recirculation pump P-B-1 and slurry pump P-B-2. The process condensate recycle pump 7 supplies process condensate from process condensate tank TK-C-100 for use as deentrainer spray 8 and as seal water. 9 10 2.5.8.3.5 Condensate Filter (F-C-1). Condensate filter F-C-1 removes particulate matter from 11 the process condensate. It is an in-line filter located downstream of the process condensate pump 12 at the -10 ft (basement) level. Two pressure indicators are located upstream and downstream of 13 condensate filter F-C-1 to measure the differential pressure. The pressure differential indicator is 14 used by operations to decide when the filter elements need to be replaced. Process condensate 15 flow is valved to bypass the filter during filter element replacement. 16 17 2.5.8.3.6 Process Condensate Filter (F-C-3). Process condensate filter F-C-3 is located on the 18 0 ft level. Filter F-C-3 is a duplex strainer unit and provides additional filtering of process 19 condensate prior to leaving the facility. The duplex design supports continuous operation by 20 permitting one screen to be online while the other is cleaned. 21 22 2.5.8.3.7 Condensate Recycle Filters (F-C-4 and F-C-5). The condensate recycle filters 23 prevent particulate material from reaching the upper deentrainer spray pads and seals for 24 recirculation pump P-B-1 and slurry pump P-B-2. The system is monitored for differential 25 pressure across the filters. 26 27 2.5.8.3.8 Radiation Monitoring, Sampling, and Diversion System (RC-3). The RC-3 28 radiation monitoring, sampling, and diversion system, located at the -10 ft. level, consists of a 29 sampler, sample receiver, and radiation monitor. Section 2.5.10 contains a description of the 30 system and operation. If the condensate does not meet discharge specifications, it is diverted by 31 the RC-3 diverter valve back to process condensate tank TK-C-100 or feed tank 241-AW-102. 32 33 2.5.8.4 Steam Condensate Monitoring Systems. The steam condensate system consists of 34 the following systems and components: 35 36
• Steam traps 242-A-60, 242-A-61, and 242-A-62 and steam strainers WWT-1, SST-3, 37 and SST-2. 38 39
• Steam condensate pressure and temperature instrumentation PI-EA1-11 and TI-EA1-5. 40 41
• Radiation monitoring, sampling, and diversion system, RC-1. 44 45
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The steam traps and piping, steam condensate weir box TK-C-103, and radiation monitoring 1 systems are located in the condenser room at the 0 ft. level. 2 3 2.5.8.4.1 Reboiler Steam Traps and Strainers. Steam traps 242-A-60, 242-A-61, and 4 242-A-62 are used to ensure that steam is held in the reboiler, where it is needed to heat waste 5 during operations. The steam traps are 2.5 in. float and thermostatic traps, designed to each pass 6 approximately 33,000 lb/hr steam condensate at system pressures. Three traps are used so that 7 during startup when condensate flows are increased, the combined capacity of all three traps is 8 ~99,000 lb/hr. Steam condensate flow to and from the stream traps is gravity flow, with all 9 condensate piping flowing downhill from the reboiler to the steam weir. At each trap, strainers 10 SST-1, SST-3, and SST-2 (respectively) are provided to keep rust and mineral deposits from 11 building up in the traps and affecting trap operation. 12 13 2.5.8.4.2 Condensate Pressure and Temperature Indication. Pressure indicator PI-CA1-11 is 14 located on the steam condensate line downstream of the reboiler, yet upstream of the steam traps. 15 Temperature indicator TI-EA1-5 is located at the same location, adjacent to the pressure 16 indicator. Both indicators are in the condenser room, just as the 4 in. steam piping comes out of 17 the wall, and upstream of the traps. The indicators are used to monitor condensate temperature 18 and pressure, and to ensure that live steam is not exiting out of the bottom of the reboiler. 19 20 2.5.8.4.3 Reserved for Future Use. 21 22 2.5.8.4.4 Flow Measurement Tank (TK-C-103). The carbon steel plate flow measurement 23 tank is 6 ft by 42 in. by 3 ft high and has a capacity of approximately 500 gal. It contains a 24 stainless steel flow measurement weir. The top of the tank is provided with a hinged cover 29 in. 25 by 42 in. wide. The design of the steam condensate weir box TK-C-103 cover, which provides 26 splash protection but does not trap flammable gas, eliminates the flammable gas deflagration 27 hazard in the weir box. Exposed carbon steel is coated with zinc chromate for corrosion 28 protection. The exterior surfaces of the tank are insulated with 1-in. thick mineral fiber. 29 30 Steam condensate from the reboiler enters steam condensate weir box TK-C-103 via a 4-in. line, 31 flows over the weir, and exits the tank through a 4-in. line. Additional streams that drain to 32 steam condensate weir box TK-C-103 are: 33 34
• Steam condensate from the vacuum condenser system steam separator and associated 35 steam traps; 36
37 • Steam condensate from the WF steam purge system; 38
39 • Seal water pump drip pan drains; 40
41 • Seal water sock filter drip pan drain; and 42
43 • PSV-EC2/EC3-1 (relief valve on raw water to condensers). 44
45
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Steam condensate in the weir flows over a v-notch type open-channel flow measurement system. 1 The level of the steam condensate on the upstream side of the v-notch is proportional to the flow 2 rate of the steam condensate. A dip tube level measurement system converts the level in the tank 3 to a steam condensate flow rate. This flow rate is reported on flow instrument FI-RC1-1. Since 4 the flow through the weir consists of steam condensate from the reboiler, as well as the other 5 water and condensate streams listed above, FI-RC1-1 is not strictly a reboiler steam condensate 6 flow measurement. 7 8 Condensate flow from the weir normally flows to the TEDF facility, unless the stream has been 9 diverted due to radiation detection. Diverted steam condensate flows to tank 241-AW-102. 10 An overflow line is also provided on steam condensate weir box TK-C-103. Overflow from this 11 tank flows to 241-AW-102. 12 13 2.5.8.4.5 Radiation Monitoring, Sampling, and Diversion System (RC-1). The RC-1 steam 14 condensate radiation monitoring, sampling, and diversion system consists of a sample cooler, 15 sample pump, radiation monitor, and proportional sampler. Section 2.5.10 contains a description 16 of the system. 17 18 2.5.8.5 Vapor Condensation and Treatment System, Operating Limits. System operating 19 limits are listed in this section, and the interlocks are discussed in more detail in Section 2.5.9.7 20 and Appendix 2C. 21 22 2.5.8.5.1 Process Condensate Sampling and Monitoring. The process condensate flow is 23 normally free of radionuclides, and contains only trace amounts of hazardous waste. Radiation 24 monitor (RI-RC3-1) measures the radiation level in a continuous flow of process condensate 25 effluent downstream from process condensate tank TK-C-100. If high radiation levels are 26 detected, diverter valve HV-RC3-3 is activated to divert the process condensate to feed tank 27 241-AW-102 and shuts down pumps P-C-100 and P-C-106 (interlock 5). 28 29 2.5.8.5.2 TK-C-100 Liquid Level Alarm. The liquid level in process condensate tank 30 TK-C-100 is controlled to maintain vacuum in the C-A-1 vessel, to prevent overflow to the feed 31 tank, and to prevent damage to process condensate tank TK-C-100 pump and agitator (if 32 operating). Liquid level in process condensate tank TK-C-100 is provided by a dip tube level 33 detection system. Condensate drain lines from the three condensers have vacuum seal lines 34 located near the bottom of the tank to prevent backflow of gases into the heat exchanger and loss 35 of vacuum. Two low-liquid-level setpoints shut down the agitator and pump P-C-100 when low 36 levels are detected. 37 38 2.5.8.5.3 Process Condensate Diverter. During normal operation the process condensate flows 39 to the LERF. The RC-3 sampling and monitoring system takes proportional samples of the 40 process condensate effluent flow. 41 42 Laboratory analysis of the pre-campaign feed samples and mid-campaign grab and/or 43 proportional samples plus total flow values are used to calculate the quantities of radionuclides 44 and hazardous materials discharged from the facility. The RC-3 sampling and monitoring 45 system is suspended when the high radiation alarm diverts the process condensate flow to 46
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process condensate tank TK-C-100 or feed tank 241-AW-102. An interlock connected to 1 diverter valve HV-RC3-3 stops RC-3 sampling and monitoring when the process condensate 2 diverter valve is in the divert position. 3 4 2.5.8.5.4 Filter F-C-1 High Inlet Pressure. Filter F-C-1 removes particulate material from the 5 process condensate. The inlet pressure alarm is set well below the rupture pressure of the filter 6 elements to alert operations when the filter elements should be replaced. 7 8 2.5.8.6 Component/Equipment Spares. Spare equipment and components are stored in 9 nearby warehouses and within the 242-A Evaporator for repair or replacement of failed 10 equipment. Contaminated equipment is generally replaced instead of being repaired for ALARA 11 considerations. 12 13 The majority of equipment in the 242-A Evaporator is designed to be replaced by use of flanged 14 connections for equipment located outside the cells and jumper connections for equipment 15 installed within the cells. The flanged and jumper connectors simplify equipment removal, 16 repair, and reinstallation. Covers are provided on rotating parts to prevent personnel clothing or 17 extremities from becoming entangled in the equipment. The equipment is also designed with 18 zirc fittings for greasing rotating parts and bearings. Special grease jumpers are used for 19 lubricating bearings and rotating parts on slurry pump P-B-2. Grease buckets are installed to 20 catch grease dripping from slurry pump P-B-2 remotely and prevent mixing lubricants with 21 process solutions. 22 23 The inventory of parts and equipment are determined by engineering analysis to maintain 24 continuity of safe facility operation and to reduce system or facility downtime. Spare parts and 25 equipment are packaged, shipped, received, stored, and handled in accordance with the 26 requirements of TFC-PLN-02, Quality Assurance Program Description, and associated TOC 27 implementing procedures. The TOC implementing procedures reflect the requirements of 28 Nuclear Quality Assurance (NQA)-1 (American Society of Mechanical Engineers 29 [ASME] [2008] Quality Assurance Requirements for Nuclear Facility Applications) for 30 inspection, preventive maintenance, and testing program to ensure the spare parts and equipment 31 inventory system functions properly. 32 33 2.5.8.7 Cold Chemical Systems. The antifoam system is the only major cold chemical 34 system (Figure 2-16) used at the 242-A Evaporator. The decontamination system and eluent 35 system hardware still exist in the 242-A Evaporator, but they are not used. 36 37 2.5.8.7.1 Antifoam System. The purpose of the antifoam system is to reduce the amount of 38 foaming that occurs in the C-A-1 vessel when processing certain waste types. Process slurry 39 could be entrained in the foam and forced through the de-entrainment pads and enter the 40 condensate collection and vessel ventilation systems. An antifoam solution is added to the 41 C-A-1 vessel on an as-needed basis to reduce foaming. 42 43 Antifoam tank TK-E-102 is used to store antifoam solutions. Three different nonhazardous 44 silicon emulsion solutions can be used. The stainless steel tank is 3 ft. by 2 ft.-8 in. high with a 45 volume of 100 gal. Antifoam solutions are typically received in 55-gal drums and transferred to 46
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antifoam tank TK-E-102 via a 6-in. port. Antifoam tank TK-E-102 is equipped with an agitator 1 and WF instrumentation. WF instrumentation is interlocked to prevent operating the antifoam 2 pump, P-E-102, and the tank agitator if low liquid levels are detected. A 2-in. line vents 3 antifoam tank TK-E-102 directly to the building exterior. 4 5 Antifoam solution is pumped from antifoam tank TK-E-102 to the C-A-1 vessel via metering 6 pump P-E-102. Metering pump P-E-102 is a positive displacement pump with an operating 7 range of 0.01 to 0.1 gal/min. The flow rate is measured by flow element FE-102-1 and 8 monitored in the control room. Metering pump P-E-102 is capable of generating high pressures 9 when dead-headed. Pressure relief valve PSV-E102-1 opens and routes the solution back to 10 antifoam tank TK-E-102 when the pressure relief setpoint is exceeded. 11 12 The antifoam solution enters the C-A-1 vessel at a point above the operating liquid level and 13 below the lower de-entrainment pad. Two check valves in series are installed in the solution line 14 to prevent the potential backflow of slurry into the antifoam system. 15 16 2.5.8.7.2 Decontamination System. There are no plans to use the decontamination system 17 (Figure 2-16). This system was used previously to reduce radiation exposure to personnel during 18 maintenance activities. 19 20 The stainless steel decontamination tank TK-E-104 has a diameter of 4 ft.-6 in. and is 5 ft.-3 in. 21 high with a volume of 620 gal. The contents can be heated or cooled by a heat exchanger that 22 has a minimum heat transfer surface area of 22 ft2. Low pressure steam is supplied to the heat 23 exchanger at ~10 lbf/in2 gauge and the resultant condensate is routed to steam condensate weir 24 box TK-C-103 through a 4-in. diameter line. Raw water is supplied to the heat exchanger at 25 ~15 lbf/in2 gauge and the used raw water is routed to the steam condensate collection system. 26 Raw water and chemicals are added to the tank through 2-in. and 10-in. ports, respectively. The 27 tank is equipped with a central stainless steel agitator to improve mixing, heat transfer, and 28 maintain solids in suspension. The tank is also equipped with a temperature element and specific 29 gravity/WF instruments. The WF instrumentation is interlocked to prevent operation of pump 30 P-E-104 and the tank agitator if low liquid levels are detected. A 3-in. line vents the tank 31 directly to the building exterior. Overflow and drain lines from decontamination 32 tank TK-E-104 flow to feed tank 241-AW-102 via the AMU room and condenser room drain 33 system. 34 35 The decontamination pump P-E-104 has a normal operating capacity of 50 to 60 gal/min. 36 37 2.5.8.7.3 Eluant Tank (TK-E-101). There are no plans to use the eluant tank and pump 38 (Figure 2-16). They were used previously to regenerate the ion exchange resin by replacement 39 when the bed was depleted. The stainless steel eluant tank has a volume of 4,200 gal and 40 measures 9 ft. high by 9 ft. in diameter. It can be cooled using an installed heat exchanger that 41 has a minimum heat transfer surface of 197 ft2. Cooling water from the jacket is routed to the 42 steam condensate system. The tank has a central stainless steel agitator to improve heat transfer 43 and keep solids in suspension. It also is equipped with a temperature element and WF/specific 44 gravity instrumentation. The WF instrumentation is interlocked to prevent operation of pump 45 P-E-101 and the tank agitator if low liquid levels are detected. Overflow and drain lines drain to 46
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the feed tank. The tank is vented to the outside and has a 3-in. line and a 10-in. port for raw 1 water and chemical addition, respectively. 2 3 The eluant pump has a normal operating capacity of 100 gal/min. 4 5 2.5.8.8 AMU Service and Utility Systems and Components. The following systems and 6 components are located in the AMU room: 7 8
• Fire Protection System Components. 23 24 2.5.8.9 HVAC Room Equipment. The following HVAC equipment is located in the HVAC 25 room and described in detail in Section 2.6: 26 27
• Preheat coils (electric), K1-2-1 and K2-2-1 28 • Prefilters, K1-7-1 and K2-7-1 29 • Final filters, K1-11-1 and K2-1-1 30 • Electric heater, HTR-K1-4-2 31 • Reheat coils (electric), K1-4-1 and K1-4-7 32 • Cooling coils, K1-3-1 and K2-3-1 33 • Supply fans, K1-5-1 and K2-5-1, with VFD 34 • HVAC instrument panel. 35
36 37
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2.5.9 Instrumentation and Controls 1 2 Instrumentation and control systems for the 242-A Evaporator are discussed in this section. 3 4 2.5.9.1 Instrumentation and Control Systems. Instrumentation and control systems for the 5 242-A Evaporator include: 6 7
• Safety Instrumented Systems (SIS). There are two interlocked systems that have been 8 developed to the requirements of American National Standards Institute 9 (ANSI)/International Society of Automation (ISA)-84.00.01-2004, Part 1, “Functional 10 Safety: Safety Instrumented Systems for the Process Industry Sector – Part 1: 11 Framework, Definitions, System, Hardware and Software Requirements.” One SIS is 12 intended to prevent flammable gas accidents in the C-A-1 vessel, and the other SIS is 13 intended to prevent the overflow of waste from the C-A-1 vessel into the process 14 condensate system (includes boil-over and carry-over [i.e., foam-over]). 15 16
• Aspects of the system providing continued safe operation during accident conditions. 17 These are systems controlled by the MCS, and by hardwired facility interlocks, that are a 18 level of safety control below that of the two SIS controls listed above. 19 20
• Monitoring safety-related variables during normal operation, abnormal operation, and 21 accident conditions to ensure the 242-A Evaporator can always be shut down safely. 22 23
• Redundancy of engineered systems that ensure process safety and safe utility operations. 24 25
• Variables and systems that require continuous surveillance and control, including the 26 confinement system, confinement barriers and associated systems, and other process 27 systems that affect the overall plant safety. 28 29
• Instrumentation and control features associated with process control, process monitors, 30 and alarms, and their relationship to one another. 31 32
• In-situ testability of the instrumentation and control systems. 33 34
• Discussion for each system describing failsafe or a state demonstrated to be acceptable if 35 conditions such as disconnection, loss of energy or motive power, or adverse 36 environments are experienced. 37
38 The primary purpose of process control instrumentation is to regulate the process and achieve 39 ‘steady-state’ operation. The ideal steady-state operation is control of the process that 40 maximizes production, enables target product density and WVR to be achieved, minimizes 41 product losses, minimizes waste, and minimizes use of services such as power, raw water, 42 compressed air, and steam. 43 44
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Instruments required to achieve the ideal state are identified as essential instruments and fall into 1 the categories listed below: 2 3
• Instruments designed to assist in maintaining steady-state operation 4 5
• Instruments that will safely shut down the process 6 7
• Instruments that can be operated in manual mode for short periods of time if the auto 8 mode fails. 9
10 These instruments provide information about the process. They may be spare or backup 11 instruments for the essential instrument and might become an essential instrument if the primary 12 instrument fails to operate. 13 14 2.5.9.2 Safety Instrumented Systems. The 242-A process uses two SIS. The C-A-1 Vessel 15 Flammable Gas Control System prevents flammable gas accidents in the C-A-1 vessel (see 16 Section 4.4.1). The C-A-1 Vessel Waste High Level Control System prevents the overflow, boil-17 over, and carry-over (i.e., foam-over) of waste from the C-A-1 vessel into the process condensate 18 system (see Section 4.4.2). These SIS are shown in Figures 2-17 and 2-18 respectively. These 19 systems were designed to standard ISA-84. The purpose of these SIS interlocks is to ensure the 20 242-A Evaporator is always in a safe state. Under normal facility operations, process control, 21 facility interlocks (Section 2.5.9.9), and facility alarms and alarm responses have been designed 22 to keep the evaporation process inside a safe operating envelope. SIS controls are designed to 23 automatically and safely shut down the evaporation process only if the normal process control, 24 process interlocks, and alarm response failed to do so. Therefore, SIS controls envelope the 25 process and are essentially invisible to operations personnel (except for MCS reporting that SIS 26 has been activated). 27 28 SIS controls consist of three essential components: 29 30
1. Sensing element; 31 2. Logic solver; and 32 3. Final element. 33
34 For each of the two SIS controls, these three components will be discussed, as well as a technical 35 basis for the need for each SIS control. 36 37 2.5.9.2.1 Flammable Gas SIS Interlock. Under certain process conditions, the potential for the 38 buildup of flammable gases in the C-A-1 vessel headspace and 42-in. vapor line and 39 E-C-1 condenser headspace exists. Process conditions that can lead to elevated flammable gas 40 concentration include the following: 41 42 • High temperature waste can cause an increase in flammable gas generation from the waste; 43
44 • The loss of vacuum in the vessel – As long as the vessel is below 200 torr, it has been 45
determined that flammable conditions are not credible; 46
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1 • The loss of purge air in the vessel – If the vessel is not under vacuum, then purge air flow 2
into the vessel can keep flammable gas below lower flammability limit (LFL) concentrations. 3 4 If the C-A-1 vessel is completely empty of waste, then there is no potential for a flammable gas 5 accident. If the vessel has been emptied by draining from the feed line, then the remaining 6 approximately 2,700 gallons of residual waste is not a flammable gas hazard (i.e., the flammable 7 gas concentration in the C-A-1 vessel cannot reach 100% of the LFL) if heat sources are stopped 8 and minimum ventilation (barometric breathing) is ensured (see Section 4.4.1). 9 10 2.5.9.2.1.1 Interlock Logic. The flammable gas interlock #S2 works by constantly monitoring 11 the C-A-1 vessel headspace pressure, the C-A-1 vessel waste temperature, and the flowrate of 12 purge air to the vessel headspace. 13 14 Purge air is only needed when the C-A-1 vessel is not at vacuum (> 200 torr). Therefore, the 15 interlock is triggered by the loss of vacuum in the C-A-1 vessel AND the loss of purge air. 16 When the C-A-1 vessel pressure increases above 200 torr, a timer is activated to give the purge 17 air system adequate time to provide sufficient purge air flow to the vessel. When the timer times 18 out, a high vessel pressure condition AND a loss of purge air condition will activate the SIS 19 interlock and initiate process shut-down actions. 20 21 High vessel waste temperature can also initiate process shut down actions, when the C-A-1 22 vessel temperature rises above 160°F. 23 24 2.5.9.2.1.2 Sensing Elements. The sensing of a flammable gas condition (loss of vacuum) is 25 provided by two independent pressure transmitters, PT-CA1-12 and PT-CA1-13. Both 26 transmitters are absolute pressure transmitting devices. Both transmitters are located on the 27 ½”I-CA1-3-M31 instrument air sensing line, in the condenser room. These pressure transmitters 28 signal to logic solvers. When the pressure transmitters detect a loss of vacuum, a 30 minute 29 timer CA1-ENCL-205 (TDR7 or TDR8) is started, which allows purge air flow time to start 30 prior to the activation of the rest of the interlock. 31 32 The sensing of purge air flow is provided by two flow instruments, FSH/FSLL-CA1-20A and 33 FSH/FSLL-CA1-20B. The flow measurement is provided by mass flow sensing elements in the 34 purge air line. The purge air line is located in the condenser room, and tees into water flush line 35 for the C-A-1 vessel spray down. This shared water/purge air line runs into four nozzles, located 36 below the lower de-entrainment pad and above the waste surface (see Section 2.5.8.1.2). One 37 nozzle on the East end of the C-A-1 vessel has been removed to allow unimpeded purge air flow 38 into the vessel. The C-A-1 vessel spray down system is no longer in use. When the loss of 39 purge air is detected, a 30 minute timer CA1-ENCL-205 (TDR3 or TDR4) is started, which 40 allows time for vessel vacuum to be established before the SIS interlock is activated. 41 42 The sensing of C-A-1 vessel high waste temperature is provided by two RTD devices, TE-EA1-1 43 and TE-EA1-1S. These RTDs signal to logic solvers. 44 45
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2.5.9.2.1.3 Logic Solvers. The logic solving for this SIS control is provided by solid state 1 instrumentation only (no programmable solvers). The logic solvers provide pressure and waste 2 temperature data to the general service MCS with signal isolation. Interlock status signals are 3 also provided to the MCS with signal isolation. 4 5 2.5.9.2.1.4 Final Elements. The final elements for the flammable gas SIS control have been 6 combined with the final element actions for the level SIS control (see Section 2.5.9.2.2). 7 Although only a subset of the total shutdown actions are required for the flammable gas SIS, all 8 actions and final elements are listed. 9 10
• Feed valve HV-CA1-1 – The feed valve is opened to ensure that draining of waste from 11 the vessel is initiated. 12 13
• Feed pump – The power to the feed pump is disconnected, to ensure that waste can drain 14 back to 241-AW-102. 15 16
• Steam isolation valve HV-EA1-5 – The steam valve is closed to ensure that no steam heat 17 can be added to the waste. 18 19
• Recirculation pump P-B-1 – The recirculation pump power is disconnected, to ensure that 20 no heat can be added to the waste from the pump. 21 22
• Vacuum break valve HV-EC1-5 – The vacuum break is opened. This final element is not 23 required by the flammable gas SIS, but is listed here since it is part of the shared shut 24 down sequence of both the flammable gas and level SIS controls. 25 26
• 30 minute timer CA1-ENCL-205 (TDR-6) is started followed by full dump through 27 HV-CA1-7 and HV-CA1-9 dump valves. Operation personnel are provided 30 minutes 28 to attempt to clear all of the sensing element parameters to a safe state. At the end of the 29 30 minutes, a full dump of the vessel is performed. 30
31 2.5.9.2.2 High-Level SIS Interlock. If the waste rises to the level of the 42-in. vapor line 32 above the C-A-1 vessel, or if a significant boil-over or foam-over event occurs, waste can be 33 introduced into process condensate tank TK-C-100 and into the process condensate piping 34 system. In this system, the waste can pose a radiation hazard, flammable gas hazard, and a 35 chemical burn hazard to facility workers. Therefore, the high level SIS interlock is provided to 36 ensure that waste cannot rise to the level of the 42-in. vapor line, and that vacuum breaking in the 37 C-A-1 vessel is initiated to prevent waste boil-over or foam-over events. 38 39 2.5.9.2.2.1 Interlock Logic. Detection of high waste level, as well as the detection of a 40 boil-over or foam-over event, is provided by one instrument for the high level interlock #S1. 41 Differential pressure sensor PDT-CA1-4, which measures the differential pressure across the 42 lower de-entrainment pad, can detect both a high level condition and a boil-over or foam-over 43 condition. In order for the differential pressure sensing element to sense a level increase, it is 44 critical that instrument air flow is provided through instrument air sensing line ½”I-CA1-3-M31. 45 Therefore, the loss of instrument air in this sensing line as detected by flow instrument 46
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FSH/LL-CA1-9 will also trigger interlock process shut-down actions. Finally, too much 1 instrument air in the higher sensing line ½”I-CA1-2-M31, can cause a false low differential 2 pressure reading in sensor PDT-CA1-4. Therefore, high air flow in this sensing line, as detected 3 by flow instrument FSHH/L-CA1-8 will also trigger process shut-down actions. 4 5 2.5.9.2.2.2 Sensing Elements. Sensing of a high level condition, or a boil-over or foam-over 6 condition is provided by the use of a differential pressure transmitter across the lower 7 de-entrainment pad. A high waste or water level, in which the liquid level in the C-A-1 vessel 8 increases above the lower sensing leg, will trigger a high differential pressure condition. 9 Likewise, a boil-over or foam-over event will also trigger a high differential pressure condition. 10 The differential pressure transmitter PDT-CA1-4 used to detect high level, boil-over, or 11 foam-over measures the pressure difference between sensing line ½”I-CA1-2-M31 and 12 ½”I-CA1-3-M31. This differential pressure transmitter signals to a logic solver. To ensure that 13 the high level condition may be detected, instrument air flow is required through the sensing 14 lines. Mass flow sensor FSHH/L-CA1-9 is used to detect low flow in line ½”I-CA1-3-M31, and 15 mass flow sensor FSH/LL-CA1-8 is used to detect high flow in line ½”I-CA1-2-M31. 16 17 2.5.9.2.2.3 Logic Solvers. The logic solving for this SIS control is provided by solid state 18 instrumentation only (no programmable solvers). The logic solvers provide differential pressure 19 data to the general service MCS with signal isolation. Interlock status signals are also provided 20 to the MCS with signal isolation. 21 22 2.5.9.2.2.4 Final Elements. The final elements for the high level SIS control have been 23 combined with the final element actions for the flammable gas SIS control (see 24 Section 2.5.9.2.2), since there is considerable overlap in the required response for each SIS. 25 Although only a subset of the total shutdown actions are required for the high level SIS, all 26 actions and final elements are listed. 27 28
• Feed Valve HV-CA1-1 – The feed valve is opened to ensure that draining of waste from 29 the vessel is initiated. 30 31
• Feed pump – The power to the feed pump is disconnected, to ensure that waste can drain 32 back to 241-AW-102 and that the addition of waste to the vessel is stopped. 33 34
• Steam isolation valve HV-EA1-5 – The steam isolation valve is closed. This final 35 element is not required by the high level SIS, but is listed here since it is part of the 36 shared shut down sequence of both the flammable gas and high level SIS controls. 37 38
• Recirculation pump P-B-1 – The recirculation pump power is disconnected. This final 39 element is not required by the high level SIS, but is listed here since it is part of the 40 shared shut down sequence of both the flammable gas and high level SIS controls. 41 42
• Vacuum break valve HV-EC1-5 – The vacuum break is opened to ensure that waste 43 foam-over or waste boil-over is stopped. Opening of the vacuum break valve 44 immediately drops the process below the saturation curve, and stops waste boiling and 45 foaming. 46
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1 • 30 minute timer CA1-ENCL-205 (TDR5) is started followed by full dump through 2
HV-CA1-7 and HV-CA1-9 dump valves. Operation personnel are provided 30 minutes 3 to attempt to clear all of the sensing element parameters to a safe state. At the end of the 4 30 minutes, a full dump of the vessel is performed. 5
6 2.5.9.3 Process Control Instrumentation. Process control instrumentation is the 7 instrumentation used to monitor and control the evaporation process, and to provide interlocking 8 and alarming functions to keep the process within safe operating parameters. When the process 9 exceeds the bounds of its safe operating parameters, particularly with respect to flammable gas, 10 high level, or boil-over events, the SIS systems listed in Section 2.5.9.2 are designed to take over 11 the process and bring the facility to a safe state. 12 13 The following instrumentation and control systems are included in this section: 14 15
• Evaporator feed control 16 • C-A-1 vessel control 17 • General process control parameters 18 • Slurry flow control 19 • Vacuum control 20 • Temperature monitoring 21 • Boil-off monitoring and effects of concentration 22 • Process interlocks (see also Section 2.5.9.9). 23
24 2.5.9.3.1 Evaporator Feed Controls. The 242-A Evaporator feed control system controls flow 25 from feed tank 241-AW-102 into the recirculating loop of the C-A-1 vessel. 26 27 2.5.9.3.1.1 Evaporator Feed Control – Major Components. The 242-A Evaporator feed 28 control system includes a coriolis flowmeter (UE-CA1-1) and a transmitter (UIT-CA1-1), which 29 provides both mass flow (FI-CA1-1) and density (DI-CA1-1) outputs on the MCS. A flow 30 indicator controller (FIC-CA1-1) controls feed to the 242-A Evaporator through a 31 diaphragm-operated valve (DOV) FCV-160, located in feed tank 241-AW-102 pump pit 32 AW-02E. A flow totalizer FQI-CA1-1 connected to FIC-CA1-1 totalizes the flow into the 33 242-A Evaporator upstream from the flowmeter. The DOV valve FCV-160 controls flow to the 34 242-A Evaporator by controlling the flow through a recirculation loop located immediately after 35 the feed pump. When the DOV is fully open, all flow from the pump is diverted back to tank 36 241-AW-102, and no waste flow is fed to the 242-A Evaporator. When the DOV is fully closed, 37 then no waste is diverted and feed flow is at its maximum. Therefore, by the use of the DOV, 38 speed control of the feed pump is not necessary. A jumper-mounted feed valve, HV-CA1-1, is 39 controlled from the MCS. Feed valve HV-CA1-1 is controlled by an air-to-close valve actuator. 40 In an emergency situation, the valve acts as a backup dump valve. Feed valve HV-CA1-1 is 41 seismically qualified, and is therefore the only qualified emergency dump valve in a seismic 42 event. 43 44 2.5.9.3.1.2 Evaporator Feed Control – Detection System and Locations. The coriolis 45 flowmeter and feed valve HV-CA1-1 are mounted in a four-head jumper located in the pump 46
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room. The jumper is mounted on nozzles D and F of the upper recirculation line for support. A 1 feed jumper connects from wall nozzle 13 to nozzle 13A of the feed jumper. An instrument air 2 jumper connects from wall nozzle 8 to nozzle 11 of the feed jumper. Therefore, feed is routed 3 inside the facility via jumpers 13 to 13A, and jumper 13A to D. Nozzle 11 provides instrument 4 air that controls the position of the block valve. Two instrument cables attached to the feed 5 jumper provide electrical signals of the flow rate and position indicators for the block valve. The 6 FIC-CA1-1 and HV-CA1-1 controls are located in the MCS. 7 8 2.5.9.3.1.3 Evaporator Feed Control – Operating Characteristics. The 242-A Evaporator 9 feed control system receives feed from feed tank 241-AW-102 at a typical rate of 10 70-130 gal/min, a maximum pressure of 275 lb/in2 gauge, and a typical feed specific gravity of 11 1.3 (specific process parameter values are selected for each campaign and are defined in a 12 Process Control Plan). The feed is pumped directly into the 28-in. recirculation loop, where it 13 mixes with slurry upstream from the reboiler. The automatic level control system maintains a 14 constant liquid level by continuous feed rate adjustment. 15 16 The feed density may change during normal operations due to slurry recycling, dilution of the 17 feed by seal water flow back from the 242-A Evaporator, transfer of feed from another DST to 18 feed tank 241-AW-102, or due to shutdowns involving flushing activities. The feed, slurry, 19 and/or steam rate can be adjusted to make changes to the slurry density. Increasing the feed rate 20 or increasing the slurry rate while maintaining a constant vessel level reduces the slurry density 21 because the recirculating slurry becomes more dilute. 22 23 Feed streams may be blended in 241-AW-102 or other DSTs to meet 242-A Evaporator or Tank 24 Farms operating limits or processing objectives. Examples include blending to reduce the 25 Cs-137 concentration in the slurry to meet the ALARA limit of 0.8 Ci/L, or to reduce the 26 ammonia feed concentration so that the ammonia released from the C-A-1 vessel ventilation 27 stack remains below the CERCLA reportable limit of 100 lb/24 h. 28 29 2.5.9.3.1.4 Evaporator Feed Control – Safety Criteria and Assurance. Interlocks are 30 provided to ensure safe operation and to place the 242-A Evaporator in a safe configuration if 31 upset or abnormal conditions occur. These interlocks are discussed in Section 2.5.9. For 32 example, C-A-1 vessel feed is prevented by interlock 12, a high liquid level detector that 33 automatically shuts off feed tank 241-AW-102 pump 241-AW-P-102 and sends an alarm to the 34 MCS. Seven other interlocks (interlocks 2, 3, 4, 14, 19, 20, and 24) shut down the feed system 35 when process control and other limits are reached. 36 37 A potentially adverse condition in the feed line may be created by water hammer. Water 38 hammer may be caused by the sudden closure of feed valve HV-CA1-1 on waste or water flow. 39 If this valve closes too quickly, a water hammer could result in the feed line that could 40 potentially damage components in the line. To control this water hammer, the feed valve is 41 controlled such that its actuation speed is slowed down to 30 seconds. 42 43 Feed valve HV-CA1-1 fails in the open position on loss of power, loss of air, or loss of MCS 44 control, which places the feed system in safe shutdown configuration until power is restored or 45 the instruments and controls are repaired. 46
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1 2.5.9.3.2 Evaporator Vessel Control and Monitoring. The control system continuously 2 monitors and controls slurry recirculation. 3 4 2.5.9.3.2.1 Evaporator Vessel Control – Major Components. Major components of the 5 C-A-1 vessel control system include the recirculation pump P-B-1 on/off controls, amperage 6 indicator, vibration sensors, seal water flow indication, pump lubrication connections, slurry 7 level indicators (Figure 2-19), slurry density indicators, and flowmeter. 8 9 2.5.9.3.2.2 Evaporator Vessel Control – Detection System and Locations. The recirculation 10 pump P-B-1 amperage indicator has one high-level alarm for monitoring pump amperage. 11 Amperage is an indication of the work being done by the pump to recirculate the slurry. An 12 electrical cable connects the pump motor with an electrical connection located in the 13 AMU room. Vibration sensors attached to the pump motor sense and transmit pump vibrations. 14 Seal water flow prevents slurry from leaking through the pump shaft and cools the seals. Grease 15 connections are provided to lubricate the pump thrust bearings. A flowmeter is mounted on the 16 lower recirculation line to measure slurry flow. Transmitters for the instruments are located in 17 the AMU room and the controls are in the MCS. 18 19 2.5.9.3.2.3 Evaporator Vessel Control – Operating Characteristics. The recirculated slurry 20 mixture is heated slightly in the reboiler to operating temperature, normally ~120 – 130°F, by 21 using 10 lbf/in2 steam. 22 23 The low-pressure steam provides adequate heat input, and the resulting low-temperature 24 differential across the reboiler helps minimize scale formation inside the tubes on the heat 25 transfer surfaces. 26 27 The heated slurry stream is discharged from the reboiler into the C-A-1 vessel, which is 28 maintained at a nominal pressure of ~60 torr (1.2 lbf/in2 absolute). A fraction of the water in the 29 slurry flashes to steam and is drawn off through two wire-mesh deentrainer pads into a 30 42-in. vapor line to the primary condenser. 31 32 The slurry can become supersaturated as evaporation occurs. Supersaturation promotes the 33 growth of existing crystals, forms some new salt crystals in the slurry liquid, and is avoided in 34 current process operation. The slurry then flows to recirculation pump P-B-1 suction via the 35 bottom of the C-A-1 vessel and lower recirculation line. The 242-A Evaporator is designed for a 36 2-min mean slurry residence time. 37 38 Indication of flow through the recirculation loop is provided by FI-CA1-3, a coriolis flow meter 39 located on the slurry sampling line. Since this flow meter is on the sampling line and not 40 actually on the 28-in. recirculation loop, this instrument only provides an indication of flow, and 41 not the true recirculation flow rate. The recirculation pump moves slurry at high velocities 42 through the reboiler to accomplish the following objectives: 43 44
• Improve the heat transfer coefficient 45 • Reduce fouling of heat transfer surfaces 46
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• Keep solids in suspension 1 • Permit large quantities of heat to be transferred with only a small change in solution 2
temperature. 3 4 The static pressure of the solution above the reboiler is sufficient to suppress the boiling point so 5 the solution will not boil in the reboiler tubes. Boiling occurs only near or at the liquid surface in 6 the C-A-1 vessel. 7 8 2.5.9.3.2.4 Evaporator Vessel Control – Safety Criteria and Assurance. Recirculation pump 9 P-B-1 is designed for fail-safe operation. Interlocks (interlocks 2, 13, 15, and 21) on 10 recirculation pump P-B-1 activate on loss of power or control and place the recirculation system 11 in a shutdown configuration until power is restored or the instruments and controls are repaired. 12 13 The C-A-1 vessel is designed for fail-safe operation. Interlock 12 activates when a high WF is 14 detected in the C-A-1 vessel and stops feed flow to the 242-A Evaporator. Interlock 15 activates 15 when a low WF is detected in the C-A-1 vessel and stops recirculation pump P-B-1 and slurry 16 pump P-B-2. As discussed in Section 2.5.9.2.2, a level SIS interlock #S1 is provided as an 17 additional safety feature, and safely shuts down the process if the normal process control of 18 vessel level is lost. 19 20 2.5.9.3.3 General Process Control Parameters. Steam flow to the reboiler (Figures 2-19 and 21 2-13) and vessel pressure control (Section 2.5.9.3.5 below) are used together to control the 22 boil-off rate from the C-A-1 vessel. This section describes steam flow control and other general 23 parameters that influence operation of the C-A-1 vessel. Pressure control of the C-A-1 vessel is 24 typically set at 40–80 torr, and is not normally adjusted during the process. Pressure control is 25 discussed in Section 2.5.9.3.5. 26 27 2.5.9.3.3.1 General Process Control Systems – Major Components. The major components 28 of the steam flow control system are steam flow indication and control instrumentation. These 29 instruments include flow regulating valves, transmitters, steam-line orifices, and temperature 30 sensors. 31 32 2.5.9.3.3.2 General Process Control Parameters – Detection System and Locations. Most of 33 the detection instruments and controls are located in the HVAC room. Some controls are located 34 on the MCS. 35 36 2.5.9.3.3.3 General Process Control Parameters – Operating Characteristics. Steam flow to 37 the reboiler controls the rate of boil-off from the C-A-1 vessel. Other process controls have 38 minor effects on the boil-off rate. In a typical operation, engineering might want to achieve a 39 WVR of 50%. This is accomplished by setting the steam flow rate and then adjusting the slurry 40 flow setpoint to achieve the desired specific gravity and/or WVR. A constant liquid level in the 41 vessel is maintained automatically by automated feed controller adjustments in the feed rate. See 42 Table 2-1 for typical operating parameters. 43 44 Reboiler inlet steam temperature is based entirely upon the saturation pressure of the steam 45 provided by the package boilers which provide saturated low pressure steam at a pressure of 46
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10 lbf/in2 (maximum of 15 lbf/in2). However, by the time the steam reaches the reboiler it is 1 usually at a pressure of 5-8 lbf/in2 due to line losses and pipe width expansion. This results in a 2 typical reboiler shell-side steam temperature of 233°F. Since the steam is not supersaturated, its 3 temperature can no longer be controlled by desuperheating, and the original desuperheater 4 controller has been inactivated. 5 6 2.5.9.3.3.4 General Process Control Parameters – Safety Criteria and Assurance. The 7 steam flow system is designed to fail-safe under abnormal or accident conditions by a set of 8 interlock (interlocks 2, 3, 4, 6, 8, 10, 20, 25, 38, and 39). 9 10 2.5.9.3.4 Slurry Flow Control. WVR is controlled by setting the slurry flow and boil-off rates. 11 For example, if the boil-off rate is 45 gal/min and a 50% WVR is desired, the slurry flow rate is 12 adjusted to 45 gal/min. The operator sets the C-A-1 vessel control level and the system 13 automatically adjusts the feed rate to 90 gal/min or the operator may manually set the feed rate to 14 maintain the C-A-1 vessel slurry level. A magnetic flowmeter on the slurry discharge line 15 measures the slurry flow rate to tank farm operations. Operators may make minor steam flow 16 adjustments to maintain a constant specific gravity. A balance is maintained between the steam 17 flow rate, the slurry specific gravity, the feed flow rate, and the vacuum. The control room 18 instrument values are compared with feed tank level dropout and slurry tank level increases to 19 verify that the calculated specific gravity and tank level changes match the target specific gravity 20 specified in the campaign process memo. 21 22 2.5.9.3.4.1 Slurry Flow Control – Major Components. The major components of the slurry 23 flow control system are the flow indicator FIC-CA1-4, the speed controller for slurry pump 24 P-B-2, the interlocks, the slurry line flush controls, and the slurry pump P-B-2 instruments and 25 controls. 26 27 2.5.9.3.4.2 Slurry Flow Control – Detection System and Locations. The slurry flow 28 indicating and control instruments and sensing elements are located on various jumpers in the 29 Pump Room; the read outs are located on the MCS displays in the control room. The flow path 30 for slurry out in the pump room starts at nozzle C on the 28–in. recirculation line, flows through 31 5 jumpers, and exits the pump room at Nozzle 19 to SL-167 and the tank farm transfer piping. 32 The jumpers on the flow path start with JA-B-[C to 13] on which the flush valves, HV-CA1-2 33 and HV-CA1-2A, the flush valve position switches, ZS-CA1-2-1, ZS-CA1-2-2, ZS-CA1-2A-1, 34 and ZS-CA1-2A-2, and the slurry flow element, FE-CA1-4, are located. The next jumper is the 35 P-B-2 Jumper on which the slurry pump P-B-2, its vibration element VE-PB-2-1, speed 36 transmitter ST-PB2-1, and coil temperature element TE-PB2-1, are located. The third jumper is 37 JA-B-[C to 4 – 40], on which both the vacuum break valve PSV-CA1-4, and a pressure relief 38 valve PSV-PB2-1 are located. The fourth jumper is JA-B-[(4) to (5)/(40) to (21)] on which the 39 slurry pressure element PE-CA1-8 is located. The final jumper is JA-B-[5 to 19] and contains no 40 instrumentation. From nozzle 19 the slurry passes through the 242-A Evaporator wall and into 41 SL-167. Once in SL-167 the slurry is now in tank farms waste transfer piping and controlled by 42 RPP-13033. 43 44 2.5.9.3.4.3 Slurry Flow Control – Operating Characteristics. The slurry flow rate is 45 controlled by varying the operating speed of slurry pump P-B-2 using the speed control. The 46
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MCS can be set to automatically adjust slurry flow using feedback from FT-CA1-4 slurry flow 1 transmitter or it can be controlled manually. 2 3 Transfer of highly concentrated or viscous slurries could plug the line to the receiver tank, so 4 transfers are monitored by the discharge pressure gauge on slurry pump P-B-2 and the slurry 5 flowmeter. The slurry pump P-B-2 flow can be increased if there are signs that the transfer line 6 is becoming plugged. Boil-down studies performed prior to the campaign are used to set product 7 specific gravity limits that do not form high solids, and thus help prevent line plugging. 8 9 When very low slurry flow rates are desired to produce high-density or high WVR slurry 10 product, slurry pump P-B-2 may be shut off and gravity flow can be used to target density or 11 WVR. Gravity flow parameters are controlled closely via the process memo, and often require a 12 follow-up of a high flow rate through the slurry line to prevent plugging. 13 14 2.5.9.3.4.4 Slurry Flow Control – Safety Criteria and Assurance. The slurry flow system is 15 designed to fail safe during abnormal or accident conditions by interlocks (interlocks 1, 7, 15, 17, 16 18, 22, 23, and 33). In addition, slurry flow valves HV-CA1-2 and HV-CA1-2A return to the 17 slurry flush position on loss of instrument air or normal power, which blocks slurry discharge 18 from the C-A-1 vessel. Slurry pump P-B-2 shuts down on loss of normal power or malfunction. 19 The fail-safe position and shutdown of the pump place the slurry flow system in a safe shutdown 20 mode until power is restored or the instruments and controls are repaired. 21 22 A potentially adverse condition in the slurry line may be created by water hammer. Water 23 hammer may be caused by two operations. The first operation is the sudden closure of the 24 HV-CA1-2 or HV-CA1-2A valves on waste or water flow. If these valves close too quickly, 25 a water hammer could result in the slurry line that could potentially damage components in the 26 line. To control this type of water hammer, the slurry valves are controlled such that their 27 actuation speed is slowed down to 30 seconds. The second operation that could induce a water 28 hammer is column separation in the line. Because of the high elevation difference between the 29 slurry valves HV-CA1-2 and HV-CA1-2A and AP tank farm, when the valves are closed on 30 waste or water flow the waste or water in the top of the transfer line could vaporize due to the 31 high negative pressures resulting from the elevation difference. Water hammer can be created 32 when the flow to the lines is reestablished and the two water or waste columns rejoin. To 33 prevent a column separation in the slurry transfer line, a vacuum breaker is installed on the 34 JA-B-[C to 4 - 40] jumper. 35 36 To prevent over pressure of the slurry transfer line from slurry pump P-B-2, a pressure relief 37 valve (PSV-PB2-1) is installed on the JA-B-[C to 4 - 40] jumper. 38 39 2.5.9.3.5 Vacuum Creation and Control. Vacuum is created in the C-A-1 vessel (Figure 2-20) 40 by an industrial standard two-stage steam eductor and controlled by an air in-bleed valve. Each 41 steam eductor has an after condenser for condensing the condensables and cooling the vapor 42 flow. Steam flow through the eductors is set by maintaining the steam supply header at 43 ~90 lbf/in2 gauge. 44 45
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2.5.9.3.5.1 Vacuum Control – Major Components. The major components of the vacuum 1 control system are: 2 3
• Two-stage steam eductors J-EC1-1 and J-EC2-1 4 • Air inbleed valve PV-CA1-7 5 • Vacuum indicator and controller instrument PIC-CA1-7 and transmitter PT-CA1-7 6 • Interlocks 7 • Pressure and temperature indicating instruments PIC-CA1-7, PI-CA1-11, TI-CA1-9 8 • Vacuum break valve HV-EC1-1 9 • Steam pressure indicating instrument PI-EA1-1. 10
11 2.5.9.3.5.2 Vacuum Control – Detection System and Locations. Most of the vacuum 12 indicating and control instruments are located in the control room. Sensing elements (pressure, 13 flow, and temperature) are located in the condenser room. The vacuum controller uses a 14 pressure transmitter which measures pressure in the vapor-liquid section of the C-A-1 vessel 15 (PT-CA1-7). The pressure transmitter is connected to instrument piping that extends through the 16 shielding wall and is attached to the side of the C-A-1 vessel in the vapor section. 17 18 2.5.9.3.5.3 Vacuum Control – Operating Characteristics. Vacuum is controlled by adjusting 19 the vacuum controller PIC-CA1-7, which controls air bleed-in valve PV-CA1-7. This controller 20 responds to vessel pressure as detected by PT-CA1-7. Another air bleed-in valve, HV-EC1-1, 21 provides immediate response to process upset conditions and acts as a vacuum breaker for the C-22 A-1 vessel. HV-EC1-1 is interlocked with other control instruments to cut off the vacuum with 23 air bleed and halt vessel boil-off if necessary. PV-CA1-7 and HV-EC1-1 allow air to flow into 24 the 6-in. vapor header that connects primary condenser E-C-1 with the J-EC1-1 eductor. 25 26 2.5.9.3.5.4 Vacuum Control – Safety Criteria and Assurance. Fail-safe vacuum control is 27 provided by interlocks (interlocks 2, 4, 14, and 20) that open the vacuum break valve HV-EC1-1. 28 Valves PV-CA1-7 and HV-EC1-1 fail open on loss of instrument air or normal power. When 29 vacuum break valve HV-EC1-1 is in the open position the vessel stops boiling, vapor flow stops, 30 steam is shut off to the reboiler, and the C-A-1 vessel is in a safe shutdown condition. The 31 242-A Evaporator remains in the safe shutdown configuration until normal power is restored or 32 the instruments and controls are repaired or replaced. 33 34 The vacuum in the C-A-1 vessel may also be cut off through vacuum break valve HV-EC1-5 as a 35 response to either of the SIS interlocks mentioned in Section 2.5.9.2, or by the seismic 36 emergency stop button described in Section 2.5.9.5.1. 37 38 2.5.9.3.6 Slurry Temperature Monitoring. The slurry temperature is influenced primarily by 39 vessel vacuum, steam flow to the reboiler, and the physical and chemical properties of the slurry. 40 Slurry temperature is one of the indicators used to determine process operation effectiveness. 41 Slurry temperature can be monitored as a backup indicator that the WVR and density are being 42 controlled in accordance with the process control plan. 43 44 Slurry temperature is also a critical contributor to the flammable gas generation rate of the waste 45 slurry. Therefore, temperature is monitored by the flammable gas SIS, as described in Section 2.5.9.2. 46
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1 2.5.9.3.6.1 Slurry Temperature Monitoring System – Major Components. Major components 2 of the temperature monitoring system are the C-A-1 vessel and recirculation line temperature 3 indicators. Each temperature indicator has dual sensor wire pairs inserted into a pipe well at the 4 point of measurement. Current flowing in each wire pair is measured and converted to a temperature 5 readout in the control room. Temperatures of the reboiler steam inlet, process condensate tank 6 TK-C-100, and inlet and outlet raw-water flows for the primary and after condensers are monitored 7 by single sensors on each system. Temperature indicators are listed below. 8 9
• TI-CA1-6 and TI-CA1-6S – C-A-1 vessel temperature and spare. 10 11
• TI-EA1-1 and TI-EA1-1S – Reboiler outlet temperature and spare. (Note that this 12 resistance temperature detector [RTD] is shared with the flammable gas SIS as described 13 in Section 2.5.9.2 above.) 14 15
• TI-EA1-7 and TI-EA1-7S – Reboiler inlet temperature and spare. 16 17
• TIC-EC1-2 – Process condensate temperature. 30 31 2.5.9.3.6.2 Slurry Temperature Monitoring – Detection System and Locations. Three dual 32 sensors are inserted into pipe wells located on the side of the C-A-1 vessel. One is located below 33 the liquid level, one is located on the upper recirculation pipe after feed flows into the 34 recirculation pipe, and one is located on the recirculation line where liquid exits from the 35 reboiler. Temperature readouts are located on the MCS. The temperature sensor on the outlet of 36 the reboiler (TI-EA1-1 and TI-EA1-1S) is shared with the flammable gas SIS. To ensure that 37 any signal from the MCS does not corrupt the temperature signal used by the SIS, an isolator is 38 used between the MCS and the SIS circuit. 39 40 2.5.9.3.6.3 Slurry Temperature Monitoring – Operating Characteristics. The slurry 41 temperature is measured in thermowells located in the slurry flowing through the C-A-1 vessel 42 and in the recirculation piping, and is displayed on the MCS. The slurry temperature changes 43 when the C-A-1 vessel vacuum changes and when the feed and slurry flow rates change. 44 A higher vacuum (lower absolute pressure) lowers the slurry equilibrium boiling point. 45 Increased feed rates pump cooler feed into the C-A-1 vessel and increased slurry pump rates 46
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transfer heated slurry to a designated slurry receiver tank. The C-A-1 vessel temperature 1 decreases slowly as cooler feed is introduced to the recirculating slurry and hotter slurry is 2 transferred out. A slow increase in C-A-1 vessel temperature indicates that either the pressure is 3 increasing or the vessel contents are becoming more concentrated. Changes in the C-A-1 vessel 4 pressure, steam flow, feed flow, or slurry flow controllers can cause the vessel temperature and 5 pressure to increase. If the flow controllers indicate equilibrium operation, the slow C-A-1 6 vessel temperature increase could indicate that higher density feed is being pumped into the 7 vessel. Adjustment of process variables, e.g., C-A-1 vessel pressure, steam flow, feed and slurry 8 flow, are made to return the system to equilibrium operation. 9 10 The temperature differential indicators (TDI) are installed on the reboiler and the de-entrainment 11 pads. The reboiler TDI (TDI-EA1-1) indicates heat transfer conditions in the reboiler. The 12 de-entrainment pad TDI (TDI-BPR-1) measures the difference in temperature between the C-A-1 13 vessel slurry and vapor flowing to the primary condenser, and is used to monitor operation of the 14 de-entrainment pads and water spray on the pads. 15 16 A lower reboiler TDI reading indicates that either the steam flow rate to the reboiler is low or the 17 reboiler tubes are fouling. A higher TDI indicates either a high steam flow rate or restricted 18 slurry flow through the reboiler. 19 20 A small de-entrainment pad temperature differential indicates that the spray system is behaving 21 normally, while a large temperature difference indicates too much spray water is flowing onto 22 the pads or the vapor flow is low. 23 24 2.5.9.3.6.4 Slurry Temperature Monitoring – Safety Criteria and Assurance. The TDIs are 25 ‘indication only’ instruments and fail-safe operation is not required. Failure of a temperature 26 monitoring system is detected easily because the reading either goes full scale or to zero 27 indication. Neither maximum temperatures nor zero temperatures are likely to exist in the 28 facility, so the temperature indicator is assumed to have failed and repair or replacement is 29 required. The exception to this is the use of TI-EA1-1 and TI-EA1-1S in the flammable gas SIS. 30 Since these are RTD type temperature sensors, they can give erroneous readings when terminals 31 become corroded, or when circuits are shorted. To account for the possibility of erroneous 32 readings in these instruments, the SIS logic solver will detect short and open circuits in the data 33 provided by the RTDs. Additionally, the use of a spare indicator will improve the reliability of 34 the SIS. 35 36 2.5.9.3.7 Boil-Off Monitoring System. 242-A Evaporator instrument systems monitor the 37 evaporation process, and information from them is used by operations to determine process 38 efficiency. The information provides backup indication that the WVR and product density 39 requirements given in the campaign run plan are being met. 40 41
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2.5.9.3.7.1 Boil-Off Monitoring – Major Components. The boil-off monitoring systems are: 1 2
• Process condensate flow indicator FI-EC1-2; 3 • De-entrainment pad pressure differential indicators (PDI) PDI-CA1-1 and PDI-CA1-2; 4 • Slurry density indicators DI-CA1-1, DI-CA1-2, and DI-CA1-3; and 5 • Slurry pump P-B-2 discharge pressure (PI-CA1-8) and flow indicator (FIC-CA1-4). 6
7 2.5.9.3.7.2 Boil-Off Monitoring – Detection System and Locations. Most of the sensors for 8 these instruments are located in the pump room and the evaporator room and connect to locally 9 mounted transmitters and electrical junction boxes in the condenser room. The MCS is used to 10 monitor the evaporation process. The primary instrument used to detect boil-off is the process 11 condensate flow indicator FI-EC1-2, located in the condenser room. 12 13 2.5.9.3.7.3 Boil-Off Monitoring – Operating Characteristics. Water boils off from the 14 surface of the slurry in the C-A-1 vessel and the resulting vapor flow causes a pressure drop 15 across the wire-mesh deentrainer pads. The pressure differential across the pads is measured by 16 the PDIs and is displayed on the MCS in the control room. Normal boil-off rates produce a 17 small pressure drop across both deentrainer pads; a higher than normal boil-off rate is detected 18 almost immediately because the higher vapor velocity produces a higher differential pressure. 19 Higher vapor velocities can lower de-entrainment efficiency by re-entrainment of liquid droplets 20 into the overhead vapor line. A high differential pressure may also indicate excessive foaming in 21 the C-A-1 vessel or the plugging of the deentrainer pads. The boil-off rate can be controlled by 22 controlling the reboiler steam flow. Foaming can be treated by introducing or increasing 23 antifoam agent to the C-A-1 vessel. 24 25 The most important instruments used to monitor slurry concentration are: 26 27
• Coriolis meter DI-CA1-3 density instrument; 28 • WF/density indicator instrumentation DI-CA1-1 and DI-CA1-2; and 29 • Slurry discharge pressure and flow rate, slurry pump P-B-2. 30
31 2.5.9.3.7.4 Boil-Off Monitoring – Safety Criteria and Assurance. The density readings are 32 ‘indication only’ and fail-safe criteria do not apply. Instrument failure does not impact 33 operational safety. 34 35 The C-A-1 vessel de-entrainment pads are designed for fail-safe operation. Interlock 14 36 activates if a high de-entrainment pad differential pressure is detected. Interlock 14 stops feed 37 flow to the 242-A Evaporator and stops boil-off by opening vacuum break valve HV-EC1-1, 38 which then activates interlock 39 and shuts off the vacuum steam jets and reboiler steam flow. 39 40 2.5.9.4 Instrument Systems and Component Spares. Spare or alternative instrumentation 41 is installed in the 242-A Evaporator to ensure safety during normal operation and abnormal 42 conditions. The instrumentation is installed in places where loss of an instrument is essential to 43 continuous operation, where repairing or replacing the instrument would cause unacceptable 44
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downtime, and where information is required during process upset and abnormal conditions. 1 Spare and alternative instruments are listed in Table 2-3. 2 3 242-A Evaporator instrumentation is designed for fail-safe operation where required. Safety and 4 essential instruments are calibrated routinely per the preventive maintenance recall system and 5 are verified to be within calibration prior to beginning a campaign. Nonessential instruments 6 also are checked routinely for operation. The instruments are retested when maintenance is 7 performed on the equipment/instruments or whenever operations/engineering determines that a 8 retest is needed. Instrument systems have pressure taps and electrical contacts so operability can 9 be verified while the facility is operating. Calibration checks are coordinated with plant 10 operations. 11 12 2.5.9.5 Evaporator Control Room. The 242-A Evaporator control room contains the MCS 13 and is the centralized location for controlling and monitoring facility activities. The MCS 14 provides process control functions, graphic displays, indicators, alarms, annunciators, 15 controllers, printed information, and other instrumentation required for facility operation. 16 Specific equipment located in tank farms is also monitored by the MCS, which initiate interlock 17 actions when specific conditions are detected (Appendix 2C). 18 19 The MCS is an industrial-grade, microprocessor-based, distributive control system. The 20 principal components include: 21 22
• Several operator consoles, 23 • Supervisory console, and 24 • Distributed multi-task controllers. 25
26 Each operator console consists of a monitor, operator interface keyboard, printer for report 27 generation, disk drive for data storage, and an alarm logger for automatic logging of alarm 28 conditions. The 242-A Evaporator can be monitored and controlled completely from each 29 console. 30 31 A supervisory console, also located in the control room, is identical to the operator consoles. It 32 can be used to monitor and control 242-A Evaporator operations and provides redundancy. 33 34 The distributed process controllers are located in the electrical room. They interface with the 35 operator and supervisory consoles via hardwired data communication links. The controllers 36 accept both discrete and analog inputs. Outputs are converted to analog signals for control loop 37 systems. 38 39 In addition to the MCS for monitoring and control of the 242-A Evaporator process, a separate 40 control system is used to monitor and control the K1 and K2 ventilation systems. This 41 ventilation control system (VCS) consists of a human-machine interface (HMI), located in the 42 control room, a building control unit (BCU) located in the electrical room, and local control units 43 (LCU) for both the K1 and K2 systems. The VCS for the K1 and K2 ventilation systems is 44 described in Section 2.5.9.10. 45 46
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The electrical room contains two dedicated air conditioning units and an uninterruptible power 1 supply (UPS) system consisting of a bank of sealed lead-acid gel cells. The air conditioning 2 units are designed to maintain the temperature and humidity in the control room under normal 3 environmental conditions. The UPS system is designed to supply power to panel board F 4 (control room) for a minimum of 22 minutes in a power outage. Panel board F supplies power to 5 the MCS and the VCS. 6 7 2.5.9.5.1 Accident/Abnormal Operation. An earthquake is the worst-case design basis 8 accident that could affect habitability of the control room. The control room was designed to the 9 1988 UBC; therefore, a design basis earthquake could make the control room uninhabitable and 10 unusable. Interlocks are designed to shut down the 242-A Evaporator, dump C-A-1 vessel 11 contents to feed tank 241-AW-102, and place the 242-A Evaporator in a safe shutdown 12 condition. The reinforced concrete structures comprising the 242-A Building will survive a 13 design basis earthquake and are expected to provide containment and confinement of 14 radioactivity following such an event. The process vessel and floor drains are designed to drain 15 back into 241-AW-102. 16 17 In the event of an earthquake, operators in the control room will activate the seismic emergency 18 stop button, (safety interlock #S3, Appendix 2C) which activates a seismically qualified 19 shutdown sequence. This function will activate the following: 20 21
• Opens feed valve HV-CA1-1 to initiate draining of waste from the C-A-1 vessel (feed 22 valve HV-CA1-1 is a seismically qualified valve, whereas the dump valves HV-CA1-7 23 and HV-CA1-9 are not); 24 25
• Shuts off feed pump; 26 27
• Shuts off recirculation pump P-B-1; and 28 29
• Closes steam valve HV-EA1-5. 30 31 Because the control room is not seismically qualified, another emergency stop button (which is 32 seismically qualified) is located on the external, southeast wall of the 242-A Building and may 33 be activated to perform the same function. 34 35 2.5.9.5.2 Control Room Habitability. Control room habitability could also be challenged by 36 releases from tank farms accidents. In such instances, the facility could be evacuated as required 37 by emergency planning. 38 39 2.5.9.5.3 Control Room Redundancy. There is no backup control room for the 242-AB 40 Building control room. The 242-A Evaporator has two SIS controls and many interlocks and the 41 process would automatically transition to the safe shutdown configuration if it were left 42 unattended for any length of time. Procedures are in place and operators are trained to shut down 43 the process in an emergency. Therefore, a fully equipped backup control room is not required to 44 protect onsite and offsite individuals or the environment. 45 46
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2.5.9.6 Instrumentation for Safe Operation. Instrumentation described in this section are 1 monitored and controlled by operations personnel. These systems provide a layer of protection 2 below the SIS system described in Section 2.5.9.2, and are enveloped by the SIS controls. If the 3 parameters for safe operation as described in this section are exceeded, SIS systems are designed 4 to safely shut down the evaporation process and empty the C-A-1 vessel of waste. 5 6 Instrumentation used to monitor and control 242-A Evaporator operations includes liquid level 7 and density, temperature, vacuum and/or pressure, flow, leak detection, radiation detection, and 8 effluent monitoring devices. The location, range and/or accuracy, setpoints, alarm features, and 9 calibration requirements for specific instruments are contained in the Preventive 10 Maintenance/Surveillance database. 11 12 2.5.9.6.1 Vessel C-A-1 Weight Factor, Density, and Liquid Level. WF represents a level 13 measurement uncorrected by density. A WF measurement of water in the C-A-1 vessel is a 14 correct level reading, but is not correct for waste because it does not compensate for the waste 15 density. WF in the C-A-1 vessel is measured using differential pressure information from dip 16 tubes and is controlled to prevent overfilling, prevent tank structural damage, and to preclude the 17 spread of contamination. One dip tube penetrates the bottom of the C-A-1 vessel in the 18 recirculation line and is used for wide-range WF indication. Two dip tubes (to provide 19 redundancy) penetrate to mid-level and are used for narrow range WF indication. Two 20 additional dip tubes (to provide redundancy) are located approximately 100 in. below the narrow 21 range dip tubes. Specific gravity is determined from the differential pressure between these two 22 pairs of dip tubes. A reference tube is located in the vapor space just below the lower de-23 entrainment pad. WF is calculated by measuring the differential pressure between the reference 24 tube and the WF dip tubes. The WF is corrected for density by dividing the height of the WF by 25 specific gravity. This corrected WF is the actual liquid level inches, regardless of whether the C-26 A-1 vessel contains water or higher density waste. Vessel level-to-volume calibration data are 27 then used to convert this level from inches to gallons. The dip tube system is designed and 28 installed to prevent liquid from backflowing into the instrument area. The dip tubes enter the 29 wall of the evaporator room 23 ft. above the operating liquid level in the C-A-1 vessel. The 30 242-A Evaporator operates under a vacuum of approximately 50 torr. Assuming that the slurry 31 density is 1.3 g/cc, the pressure in the C-A-1 vessel would have to exceed 13 lbf/in2 above 32 atmospheric pressure to back up liquid into the instrument area. In addition, the dip tubes are 33 slightly pressurized and air flows continuously into the vessel. Therefore, under normal 34 (vacuum) operations there is no possibility of backflow or back-siphoning of waste into the 35 condenser room through the dip tube system. However, when the C-A-1 vessel is not under 36 vacuum and the waste is at normal operating level, the 23 ft. elevation difference between the 37 waste level and the dip tube high point is not adequate to prevent back-siphoning of waste 38 through the dip tube line. As long as instrument air is routed through the dip tube sensing lines, 39 back-siphoning is not possible. However, during dip tube flushes the dip tubes are completely 40 full of water and the potential for back-siphoning exists. For this reason, water to the dip tube 41 flush system is protected by a backflow prevention device PSV-RW-3, located at the raw water 42 line high spot in the condenser room. This device is a check valve which is designed to open and 43 break the vacuum in the water system upon detection of vacuum or back-siphoning conditions. 44 45
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The five dip tube sensing lines that penetrate the C-A-1 vessel below the waste surface are prone 1 to waste plugging during evaporation operations. Plugging of the dip tubes is detected by 2 discrepancies in the level or specific gravity readings between the redundant level and specific 3 gravity instruments. To enable operations personnel to flush the dip tubes and clear waste plugs 4 and crystallization that occurs on the dip tubes, a dip tube flushing manifold is located in the 5 condenser room. This flush manifold allows operations to flush the five below-waste level 6 sensors, and to follow the flush with a brief air blow of the line to restore the sensing line to 7 operation. As mentioned above, a backflow prevention device is installed on the water line to 8 this manifold to prevent back-siphoning of waste into the dip tube manifold and into the raw 9 water system. 10 11 High- and low-level C-A-1 vessel alarms signal the operator when the liquid level is approaching 12 liquid levels either below or above the desired range of liquid levels specified by process 13 engineering. 14 15 The liquid level in the C-A-1 vessel must be controlled to prevent overfilling the vessel and 16 plugging or damaging of the de-entrainment pads. C-A-1 vessel overflow could reach the 17 process condensate tank TK-C-100, which would cause a significant increase in condenser room 18 radiation levels. Operators and RCTs would be unable to enter the room and perform normal 19 surveillance activities until the tank contents were pumped out and the tank and associated lines 20 decontaminated. Due to the serious consequences of this event, waste overflow or boil-over of 21 the C-A-1 vessel is further protected by the level SIS (see Section 2.5.9.2). 22 23 A minimum liquid level is maintained in the C-A-1 vessel to control scale formation on the 24 reboiler tubes and prevent cavitation in recirculation pump P-B-1. The liquid level is maintained 25 just above the outlet pipe that exits from the reboiler into the C-A-1 vessel. The level helps 26 prevent vapor bubbles from forming inside the reboiler tubes, which creates a potential for the 27 upper part of the reboiler tubes to become dry and for scale to deposit on the tube walls. High 28 solution velocity through the reboiler tubes also reduces scale formation. 29 30 2.5.9.6.2 Vessel C-A-1 Temperature Monitoring. Specifications limit the C-A-1 vessel 31 temperature to 200°F. The purpose of this specification is to prevent thermal damage to either 32 the C-A-1 vessel or in the pipelines through which the slurry flows. The normal operating slurry 33 temperature in the C-A-1 vessel is < 140°F. Waste and steam temperature is limited by the 34 maximum possible temperature of the steam from the package boilers, which provide saturated 35 low pressure steam at a pressure of 10 lbf/in2 (maximum of 15 lbf/in2). However, by the time the 36 steam reaches the reboiler it is usually at a pressure of 5–8 lbf/in2 due to line losses and pipe 37 width expansion. This results in a typical reboiler shell-side steam temperature of 233°F. 38 39 Calibration of flow instruments, transmitters, recorders, and alarm switches are verified prior to 40 starting a campaign with feed from tank farms. 41 42 2.5.9.6.2.1 Temperature Instruments. Most of the tanks, vessels, and condensers have 43 temperature-indicating instruments used by the operators for process control. The condensate 44 temperature in process condensate tank TK-C-100, slurry temperature in the C-A-1 vessel, and 45
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the condenser temperatures are monitored to ensure that facility operation is within operational 1 limits. 2 3 Inlet steam temperature for the reboiler is controlled by a package boiler system that is outside 4 the scope of this DSA. Temperature alarms in the process recirculation loop are set to alarm at a 5 temperature below the alarm point of the flammable gas SIS. The temperature on the outlet of 6 the reboiler, as measured by TE-EA1-1 and TE-EA1-1S, is interlocked to close valve FV-EA1-1 7 upon indication of temperature > 150°F (interlock #45). 8 9 The thermocouples are single- or dual-point wire pairs installed inside pipes with a welded end 10 piece. The thermocouple pipe extends inside the vessel or pipe, providing direct contact with the 11 solution or gas. The thermocouple is inserted into the pipe to the pipe end, providing contact 12 with the pipe end cap. The thermocouple, therefore, senses the temperature of the solution or gas 13 by measuring the temperature of the pipe end cap. The thermocouple pipe protects the 14 thermocouple from chemical deterioration by the medium being measured. 15 If a thermocouple ceases to function, the instrument technician replaces it by withdrawing the 16 failed pair of wires and inserting a new thermocouple into the pipe. Thermocouple replacement 17 does not require shutting down the facility because the thermocouple does not have direct contact 18 with the solution. If the thermocouple provides input to a controller for the process, the operator 19 can operate the process in the manual mode when the thermocouple is being replaced. 20 Thermocouple replacement might require plant shutdown depending on the use and location. 21 Temperature readings are taken and recorded by operators and the computer monitoring system 22 as specified by the Engineering organization. 23 24 RTDs are also used to measure temperatures. RTDs are metallic materials in which a change in 25 temperature causes the resistance to change. The resistance change is converted to an electrical 26 signal that indicates the temperature at the RTD location. RTDs generally are metals insulated 27 by glass or ceramic materials encased in a stainless steel sheath. These materials have excellent 28 resistance to radiation damage. Like thermocouples, RTDs are installed in pipe wells that 29 prevent the sensor and associated wiring from contacting the process liquids or vapors. 30 31 Temperature sensors are used to detect gas temperatures, control electric heaters, and shut down 32 equipment when a temperature limit is exceeded. Usually there are no redundant sensors except 33 for the installed spares for TE-CA1-6, TE-EA1-1, and TE-EA1-7. When a sensor fails, it will 34 indicate either a full scale or zero reading, either of which means the sensor should be replaced. 35 36 In the case of the electric heater on the vessel ventilation exhaust stream, a temperature 37 difference controller adjusts the heater current to control heating of the gas. Thermocouples are 38 used to protect parts of the equipment where an overtemperature would cause the equipment to 39 fail/deteriorate. When the set-point temperature is reached, the instrument shuts down the heater 40 to protect the equipment from high temperature failure/deterioration. 41 42 2.5.9.6.3 Vacuum/Pressure Instruments and De-entrainment Pad DP Instruments. The 43 C-A-1 vessel vacuum is controlled and monitored to provide low-temperature water evaporation 44 of the feed flow. Low-temperature operation provides a large temperature difference between 45 the low-pressure steam and the solution temperature. The large delta temperature between the 46
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steam and the waste provides excellent heat transfer between the steam and the solution and 1 decreases the size of the surface area required for the E-A-1 reboiler. Each of the two 2 de-entrainment pads in the vapor-liquid separation section of the C-A-1 vessel has pressure 3 differential indicators. A higher than normal pad ∆P reading indicates potential pad plugging, 4 while a low reading indicates a low gas flow or a breached pad under normal operation. High 5 alarms for the vacuum/pressure indicators warn operators of changes in the operating mode, 6 which requires attention to return to normal operation. 7 8 To ensure that flammable gases cannot build up in the C-A-1 vessel, the vessel is operated either 9 under vacuum or with purge air to the vessel when the vessel contains waste. To ensure that 10 purge air is running to the vessel when there is no vacuum, interlock #56 opens purge air flow 11 when the vacuum is taken off. 12 13 Each condenser has both local and remote vacuum indicators to assist in controlling and 14 monitoring the process. 15 16 High alarms warn the operators of operating conditions outside the desired ranges. The 17 additional vacuum gauge mounted on each condenser serves as a backup vacuum monitor. 18 19 Differential pressure instruments are used throughout the 242-A Evaporator facility to determine 20 tank vacuum, deentrainer pressure drop, filter pressure drop, line pressure and vacuum, specific 21 gravity of solutions, tank liquid level, and water flow rate. These instruments are primarily 22 indicators of process conditions, and have no control capability. They usually contain a 23 diaphragm to sense pressure differences between two selected process points or between a 24 selected process point and atmospheric pressure. The instruments are calibrated except for some 25 local pressure gauges that are precalibrated by the manufacturer. The calibrated instruments 26 have valves for isolating the instrument, and ports for connecting them for testing. The 27 instruments are tested/calibrated in place, but occasional major repairs might require they be 28 removed. 29 30 These instruments normally fail in the zero-indicating mode or the full-scale mode. There are no 31 redundant instruments for differential pressure instruments. There are other instruments in the 32 system for indicating process conditions that provide information to ensure the equipment is 33 operating normally. This means that the loss of a single instrument does not require the system 34 be shut down. The other instruments are used temporarily to maintain control of the process 35 until the failed instrument is repaired or replaced. Some of the differential pressure instruments 36 are interlocked to shut down parts of the system. 37 38 2.5.9.6.4 Flow Instruments. Flow instruments indicate and measure the flow rates of process 39 and sample streams. Flow control valves receive signals from the flow instruments and control 40 process flow rates. The flow instruments consist of a variety of instrument types sized for the 41 individual flow range, pipe diameter, and medium flowing through the instrument. The 242-A 42 Evaporator process has magnetic-, corriolis-, turbine-, weir-, and rotameter-type flow 43 instruments. Both pneumatic and electrical signals transmit flow information to controllers, 44 alarms, and indicators. The flow controllers transmit both pneumatic and electrical signals to 45 control the flow. The electrical signals control the speed of pumps or operate DOVs. Some of 46
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the control valves are needle valves for controlling air and water flow rates. Flow totalizers are 1 used in the process to accumulate total flow during the desired time period. None of the flow 2 instruments have redundant flow instrumentation. The facility can be run when some of the 3 automatic flow controllers become disabled by adjusting the flow in the manual mode, which 4 requires more operator attention than during normal operation to maintain steady-state operation. 5 6 During startup, operators monitor the flow instruments frequently. This ensures the flow 7 instruments are operable and functioning correctly. Any changes from normal operation are 8 noted. The operator then attempts to exercise the flow instrument to determine the causes of 9 abnormal operation. Finally, a request is made for the instrument technician to repair or replace 10 the failed instrument. 11 12 The flow instruments, transmitters, recorders, and alarm switches are calibrated periodically, 13 when the 242-A Evaporator is operating, to ensure operability. Also, the operators may request 14 an instrument be calibrated any time it appears to be operating abnormally. 15 16 Another important function of facility flow instruments is to support the MCS calculations of 17 facility and tank farm material balance. Most of the important facility flow meters include an 18 MCS generated totalizing function. A tank farms material balance compares the totalized 19 quantity of feed flow into the facility and slurry flow from the facility and compares these totals 20 with measured tank levels for the purpose of transfer line leak detection. A facility (or process) 21 material balance performs a flow total of waste, process condensate, steam condensate, and water 22 streams within the facility to ensure that all liquid flows are accounted for and to provide leak 23 detection. 24 25 2.5.9.6.5 Leak Detection Instruments. Pipe, valve, and vessel integrity are monitored by leak 26 detectors installed in sumps, sample hoods, and valve pits. The typical leak detection system 27 includes a conductance probe connected to alarming and shutdown devices. A conductance 28 probe completes an electrical circuit when the conducting medium touches the probe. The 29 electrical circuit then activates an alarm circuit alerting operating personnel of liquid leaks. 30 31 The leak detection systems in the tank farms are external to the 242-A Evaporator facility and are 32 discussed in RPP-13033. Process condensate transfer systems are discussed in 33 HNF-SD-LEF-ASA-002, 242AL Liquid Effluent Retention Facility Auditable Safety Analysis. 34 During normal operations, the leak detectors require electrical power to provide leak detection 35 capabilities. 36 37 The leak detectors in the feed and slurry sample enclosure in the load-out and hot-equipment 38 storage room are not connected to the 242-A Evaporator pump shutdown circuitry. 39 40 If a leak is detected in the feed and slurry sampler enclosure, the leak detector circuitry will also 41 alarm at the MCS in the control room. A leak will not activate any hardwired interlocks or pump 42 shutoffs. However, an alarm at the MCS, indicating a leak, will initiate operator responses in 43 accordance with applicable procedures. Additionally, the sample enclosure is within the load-out 44 and hot-equipment storage room with floor drains to the pump room sump. Should a leak occur, 45
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the building will confine the leak, and a loss of power to the detector will not result in an adverse 1 impact to the onsite environment. 2 3 If a leak or instrument failure alarm is detected in tank farms, feed pump 241-AW-P-102 and 4 slurry pump P-B-2 are manually shutdown. In the raw water system, the drain lines from 5 backflow preventers BFP-RW-1 and BFP-RW-2 are equipped with leak detectors that indicate 6 that there is a backflow condition. 7 8 2.5.9.6.6 Radiation Detection Instruments. Types, locations, operations, setpoints, interlocks, 9 alarms, and calibration requirements are described in Section 2.7.2 and Chapter 7.0. 10 11 2.5.9.7 Effluent Monitoring Instruments. This section describes instrumentation and 12 interlocks installed on the 242-A Evaporator effluent systems. 13 14 2.5.9.7.1 Steam Condensate Radiation Monitoring and Sampling System (RC-1). Steam 15 condensate from the 242-A Evaporator is normally discharged to the TEDF, but can be diverted 16 to feed tank 241-AW-102 upon detection of radiation. Radiation in the steam condensate is an 17 indication of a tube leak in the E-A-1 reboiler. The stream is monitored continuously with 18 radiation detection instruments, and grab sample ports are available to obtain samples for 19 laboratory analysis. 20 21 A failure of the radiation detector (e.g., loss of power) or a high radiation level in the steam 22 condensate will result in an alarm at the MCS and will activate hardwired interlock 25 (see 23 Section 2.5.9.7). When this interlock is activated, it diverts the flow of the steam condensate 24 from the TEDF to feed tank 241-AW-102. 25 26 The steam condensate is routed through a 500–gal steam condensate weir box TK-C-103, which 27 is equipped with a flow-measurement weir. A continuous sample from steam condensate weir 28 box TK-C-103 passes through a sample cooler to reduce the condensate temperature; then the 29 sample is pumped by pump P-RC-1. The flow through the sampler is measured by a rotameter. 30 The sample continues on through the radiation detector and then is returned to the sample stream. 31 It then passes through a pH and conductivity meter before it is returned to steam condensate weir 32 box TK-C-103. 33 34 The steam condensate is sampled, using grab sample taps in accordance with the TEDF interface 35 control document (ICD) (RPP-RPT-59117). 36 37 The sample flow can be diverted to bypass the radiation cell, RE-RC1-1, and allow the cell to 38 drain to obtain a background radiation reading as directed by engineering or by operations. The 39 radiation cell is flushed if the background level is increasing. If high radiation is detected in the 40 cell, the steam condensate flow is diverted to the feed tank. 41 42 2.5.9.7.2 Cooling Water Radiation Monitoring and Sampling System (RC-2). Used raw 43 water from the primary and after condensers is discharged to the 200 Area TEDF Pump 44 Station 3. A small portion of this flow is routed through the radiation detector, RC-2, which 45 works essentially the same as RC-1, then past a pH and conductivity meter. The sample stream46
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then is returned to the main line. The proportional sampling system consists of an Isolok2 1 sampler mounted on the 12 in. used raw-water line. 2 3 The used raw water is sampled using grab sample taps in accordance with the TEDF ICD 4 (RPP-RPT-59117). 5 6 The sample flow can be diverted to bypass radiation cell RE-RC-2-1 and the cell can be drained 7 to check the radiation background reading, as directed by engineering or operations. The 8 radiation cell can be flushed if the background level is increasing. During sample system 9 shutdown, draining, and background checking, approximately 18,000 gal of used cooling water 10 flows to the 200 Area TEDF. 11 12 A high radiation reading on the cooling water stream is not anticipated, and this stream cannot be 13 diverted. If the stream becomes contaminated, a facility shutdown is required. 14 15 2.5.9.7.3 Process Condensate Radiation Monitoring and Sampling System (RC-3). Process 16 condensate from the 242-A Evaporator normally is discharged to the LERF via process 17 condensate tank TK-C-100. Grab sampling can be performed using inline sample taps. 18 Proportional sampling can be performed by routing a portion of the process condensate through a 19 radiation monitoring and diversion system, RC-3, which is similar to RC-1 and RC-2. This 20 radiation monitoring sample stream is routed to process condensate tank TK-C-100 after passing 21 through RC-3. The sample is routed and collected by a system similar to that used for RC-2. 22 Condensate flow can be diverted to allow the radiation cell, RE-RC3-1, to drain to provide a 23 check of the radiation background. The radiation cell can be flushed if the background level is 24 increasing. Radiation readings that correspond to activity levels greater than the levels analyzed 25 in HNF-SD-WM-SAD-040, Liquid Effluent Retention Facility Final Hazard Category 26 Determination, result in diversion of the process condensate back to process condensate tank 27 TK-C-100 or the feed tank 241-AW-102. 28 29 A failure of the radiation detector (e.g., loss of power) or a high radiation level in the process 30 condensate will result in an alarm at the MCS and will activate hardwired interlock 5 31 (see Section 2.5.9.7). When interlock 5 is activated, it diverts the flow of process condensate 32 from the LERF basins to the process condensate tank TK-C-100 or the feed tank 241-AW-102. 33 34 Because of the potential for high NH3 and organic (acetone, butyl alcohol, tributyl phosphate, 35 etc.) concentrations and the potential to exceed the RCRA and dangerous waste limits in the 36 process condensate, the process condensate stream is routed to the LERF and stored for 37 processing at the ETF. During normal operations, the RC-3 monitoring and diversion system is 38 used to ensure this stream is within specified limits for radioactivity. Additionally, sample 39 analysis can be used to verify process condensate composition and to compare it to pre-campaign 40 analyses and calculations. 41 42
2 Isolok is a registered trademark of Bristol Equipment Company, Yorkville, Illinois.
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2.5.9.7.4 Slurry Sampler. The 3-in. recirculation bypass loop connecting the recirculation 1 pump section, nozzle A, with the pump discharge, nozzle B, is routed into a sample enclosure 2 located in the load-out and hot-equipment room. Samples of 242-A Evaporator slurry in the loop 3 can be obtained within the sample enclosure. A discussion on the sample enclosure leak 4 detection system is provided in Section 2.5.9.6.5. 5 6 Slurry samples are available by extracting a small portion of the slurry stream via an Isolok 7 sampling device. The samples extract flow directly into sample bottles that are loaded in 8 shielding casks and transferred to the laboratory for analysis. Instrument air and hot water are 9 supplied to the sample enclosure to operate the Isolok sampler and flushing, respectively. 10 11 2.5.9.7.5 Vessel Vent Stack Sampling. High NH3 concentrations in some feeds have increased 12 the potential for releases of ammonia gas from the vessel vent stack. Ammonia releases from the 13 vessel ventilation exhaust stack can be monitored by a continuous ammonia monitor installed on 14 the stack, if necessary, based on pre-campaign sample analysis. This decision is documented in 15 the campaign process control plan and/or process memos. Detector tube sampling capability is 16 maintained as a contingency. The monitor samples and measures the ammonia emissions 17 discharged into the atmosphere through the vessel stack to assure compliance with environmental 18 safety regulations. The CERCLA reportable quantity for gaseous ammonia discharge to the 19 environment is 100 lb/24 h. The ammonia monitor is self -contained, withdrawing gas samples 20 from a 1 in. stainless steel tube penetrating the 8-in. vessel ventilation stack downstream of the 21 vessel ventilation stack monitor. After measuring the discharge, the sample gas is returned to the 22 vessel ventilation stack to be discharged to the atmosphere. The ammonia concentration is 23 monitored continuously on the MCS and hardwired to alarm in the event of high ammonia 24 concentration or monitor failure. If the vessel ventilation ammonia monitor indicates the 25 ammonia level might exceed 50 lb/24 h if no action is taken, then engineering is notified to trend 26 and evaluate the discharges and give appropriate process direction to lower the ammonia 27 discharge level. 28 29 2.5.9.7.6 Other Monitoring Instrumentation. Process condensate tank TK-C-100 is equipped 30 with two interface dip tubes in addition to the WF dip tubes. The interface dip tubes were 31 installed to detect a floating organic layer on the surface of the tank liquid level. Process 32 condensate tank TK-C-100 liquid-level instrumentation has both high- and low-level alarm 33 functions. Process condensate tank TK-C-100 is not equipped with a density indicator. Low 34 liquid level interlocks shut down the pump and agitator and a low liquid level alarm alerts the 35 operator that the pump should be shut down, if it is operating, to prevent pump damage. 36 37 Process condensate tank TK-C-100 has an overflow line that drains back to the feed tank. This 38 line prevents overfilling the tank and subsequent water flow into the condenser room. There are 39 no safety issues associated with overflowing process condensate tank TK-C-100. 40 41 Any overflow liquid becomes feed for the 242-A Evaporator run and increases slightly the 42 operating costs of the campaign by diluting the feed tank contents and increasing the 43 242-A Evaporator running time. 44 45
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A minimum level must be maintained in process condensate tank TK-C-100 to maintain vacuum 1 control in the condensers. The drain lines from the three condensers extend to near the bottom of 2 process condensate tank TK-C-100 to prevent reverse flow of vapors to the condensers. The 3 liquid level must be above the bottom of the drain lines to maintain vacuum control. 4 5 Antifoam tank TK-E-102 is monitored for liquid level using two dip tubes. The tank has both 6 high and low liquid level alarms, a locally mounted level indicator, and interlocks that shut down 7 the pump and agitator. This system is used when processing waste streams that are known to 8 foam in the C-A-1 vessel. The system can also be used when the operators determine that a 9 foaming condition has developed in the C-A-1 vessel and using the antifoam might be helpful to 10 control the process. This tank also has an overflow line that drains back to feed tank 11 241-AW-102. 12 13 All instrumentation for the liquid-level and density indicators and controllers is checked 14 periodically to determine if it is operational and functioning properly. The high- and low-level 15 alarm switches and annunciators also are tested periodically. The calibration overdue list is 16 reviewed for impacts to facility operations prior to facility startup. The instruments are repaired 17 or replaced when instrument calibration and testing determines that monitoring or controlling 18 functions are outside the instrument specifications. 19 20 Leak detection is provided at 1,000 foot intervals along the PC-5000 process condensate transfer 21 line. A leak detection system alarm anywhere along the 3-inch transfer line will initiate operator 22 actions to verify and shut down the 242-A Evaporator process condensate transfer equipment. 23 24 2.5.9.8 Data Logging. The computer monitoring system for the 242-A Evaporator contains 25 data logging features that assist operations in monitoring and controlling the process. The data 26 logging features are divided into three general categories: historical trending, alarm information 27 and message logging, and backup storage media (i.e., magnetic tape). 28 29 2.5.9.8.1 Data Trending. The control room operator can display data trends of analog input 30 devices (i.e., a temperature instrument, flow instrument, pressure instrument, etc.). The span of a 31 current trend display is approximately 1 hr and 2, 8, or 24 hr for a historical trend. The data can 32 be printed or displayed on the screen to assist in controlling and monitoring plant performance. 33 34 2.5.9.8.2 Alarm Information and Message Logging. The computer receives analog and 35 discrete signals from field instruments. The analog signals represent process values (flow, 36 pressure, temperature, etc.) the computer can use to generate alarms. Discrete signals indicate 37 equipment status and alarms. The alarm and equipment status messages generated by processing 38 operations are recorded continuously by the computer. The computer also records operator 39 commands (start, stop, open, close, acknowledge, etc.). These records can be viewed by facility 40 personnel. 41 42 2.5.9.8.3 Backup Storage Media. Process data, alarm, and message information is stored 43 electronically and is copied at regular intervals to backup storage media. Backup media 44 provided for storing data required by state and federal laws, complies with DOE regulations, and 45
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provides the facility with longer term information. This backup medium is stored in the control 1 room and satisfies the requirement for long-term data storage. 2 3 2.5.9.9 System Interlocks. Interlocks described in this section and in Appendix 2C protect 4 equipment, facility, and personnel. These interlocks provide a layer of protection below the SIS 5 system interlocks described in Section 2.5.9.2, and are enveloped by the SIS controls. If the 6 parameters for safe operation as described in this section are exceeded, SIS systems are designed 7 to safely shut down the evaporation process and empty the C-A-1 vessel of waste. 8 9 Interlocks are used to protect the 242-A Evaporator SSCs from damage and to ensure the safety 10 of 242-A Evaporator personnel, co-located workers, and the public. Interlock functions vary 11 from shutting down key pieces of equipment to shutting down the entire process when abnormal 12 conditions occur. 13 14 All interlocks are designed for fail-safe operation (i.e., process control might be lost during an 15 accident or equipment/instrument failure, but control of the 242-A Evaporator feed is maintained 16 and the 242-A Evaporator is placed in a safe-shutdown configuration). Interlocks are tested 17 periodically when maintenance is performed on interlocked equipment/instruments or when 18 operations and/or engineering determines they need to be tested. 19 20 Tank farms are responsible for all slurry feed and slurry product transfer systems beginning at 21 the 242-A Evaporator wall exterior. Operations of some of the interlocks in the 242-A 22 Evaporator affects tank farm systems and are listed in detail in Appendix 2C. 23 24 Appendix 2C lists all interlocks at the 242-A Evaporator and includes the activating condition 25 and the interlock response. 26 27 2.5.9.10 Ventilation Control System. The VCS is used to monitor and control the K1 and K2 28 ventilation systems, and consists of both the hardware and software necessary to monitor and 29 control critical functions of the ventilation systems. The VCS is programmed with all necessary 30 interlocks to safely operate or shut down ventilation systems. The VCS controls air flow and 31 pressure in both the K1 and K2 systems to ensure negative pressure in the K1 rooms and positive 32 pressure in the K2 rooms. 33 34 The hardware associated with the VCS consists of the HMI, the BCU, and the LCUs for both the 35 K1 and K2 systems. 36 37 2.5.9.10.1 Human-Machine Interface. The HMI for the K1 and K2 ventilation systems is 38 located in the control room. The HMI includes a standard computer processor, monitor, 39 keyboard, and mouse. The HMI provides an interface between the operators of the K1 and K2 40 systems and the VCS field devices (K1 and K2 LCUs and the chiller unit) through the BCU 41 control unit. Operations personnel use the HMI to perform daily tasks such as viewing 42 equipment and system status information, changing system setpoints, and viewing the alarm and 43 event log. Remote access to the HMI is available via modem. 44 45
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2.5.9.10.2 Building Control Unit and Local Control Units. The LCU is a programmable 1 controller which provides direct digital control of a variety of HVAC equipment for both the K1 2 and K2 systems. Signal output from the HVAC equipment is routed directly to one of two LCU 3 units. One LCU controls operation of the K1 system (LCU-K1) and the other controls the 4 operation of the K2 system (LCU-K2). Each LCU contains three MP581 controllers, relays, 5 power supplies, and terminal blocks. A COMM5 jack in each LCU can be used to connect a 6 laptop to allow operators to change set points, change scheduled occupancy times, identify and 7 troubleshoot problems, view and reset controller alarms, and manually override outputs. 8 Operation of the LCUs is independent; meaning that if one LCU fails the other will continue to 9 function. Interlock, monitoring, and control functions for the K1 and K2 systems are contained 10 in the programming of the LCU units. 11 12 The BCU provides VCS control through a single integrated system (i.e., coordinates LCUs in 13 their operation in the field). All inputs from pressure, temperature and flow sensors, fan status, 14 fan control, damper control, and alarms are routed to the operator through the BCU. The BCU is 15 connected to the HMI through a standard Ethernet connection. The BCU contains two 16 communication ports, one for the K1 and K2 LCU controllers and one for the chiller unit. 17 Communication is via a twisted shielded wire between the BCU and LCU (port 1) and the chiller 18 unit (port 2). 19 20 2.5.9.10.3 Ventilation Control System Functions. The 242-A Evaporator VCS HMI software 21 performs the following functions: 22 23
• HMI – The VCS includes all necessary graphical screens and capabilities to operate a 24 fully functional graphical control system. Screens include an overall building layout 25 showing room temperatures, room pressures, alarms, and major equipment status. 26 27
• User levels – The VCS provides levels of security and operational control designed for 28 use by operations, maintenance personnel, engineering, and guests. 29 30
• Historical Data and Trend Analysis – The software measures various inputs in the 31 system. Sampling times are adjustable from 1 minute to 2 hours, in 1 minute intervals. 32 Sampling configuration and custom reports on trend data are available to the user through 33 the trending application. Trends may be printed or saved as a file. Data is stored on the 34 HMI computer. 35 36
• Alarm Messages – Alarm messages annunciate through the HMI computer. The VCS has 37 an alarm application which creates alarm logs, alarm messages, event messages and 38 graphics, dial out capabilities, and event routing. 39
40 The VCS is powered by the UPS system (see Section 2.8.1). When normal power is lost, all K1 41 and K2 fans shut down. The control system senses this upset and automatically enables the 42 backup K1 exhaust fan (K1-5-2) to operate, and K1-5-2 ramps up as soon as power is restored to 43 the fans VFD. 44 45
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2.5.9.10.4 External Interfaces. Field I/O signals (from K1 and K2 field devices and from the 1 chiller unit) are connected to the LCUs using standard industry wiring practices. 2 3 The VCS is a dedicated monitoring and control system, and is not connected to any other local 4 area network or to the MCS, with an exception of an HVAC trouble alarm signal to the MCS and 5 to the fire alarm panel contacts. MCS and fire alarm panel contacts are hard wired directly to the 6 LCUs. The 242-A Evaporator VCS HMI does not access any existing MCS, programmable 7 logic controllers, or HMIs. The 242-A Evaporator VCS HMI communicates with the K1 and K2 8 LCUs and the chiller unit only. 9 10 2.5.9.10.5 Ventilation System Interlocks. Several interlock functions have been programmed 11 into the VCS, to ensure correct system flow rates, temperatures, and pressures are maintained. 12 Other interlocks are hard-wired into the system. To capture all interlocks together, both VCS 13 and hard-wired interlocks are summarized as follows. 14 15 Note that ventilation interlocks are different from the process interlocks listed in Appendix C2, 16 since ventilation interlocks are unrelated to the evaporation process. The one exception to this is 17 process interlock 11, which shuts down the exhaust fans if high radiation is detected in the stack 18 (noted below). 19 20 K1 system interlocks: 21 22
• Supply fan K1-5-1 is interlocked to shut down on loss of K1 exhaust. When both exhaust 23 fans K1-5-2 and K1-5-3 are off, power is removed to fan K1-5-1 (VCS software 24 interlock). 25 26
• Exhaust fans are interlocked to switch from the fan (K1-5-3) to fan (K1-5-2), or fan 27 (K1-5-2 to K1-5-3) upon the detection of low flow (VCS software interlock). 28 29
• Exhaust fans K1-5-2 and K1-5-3 are interlocked to shut down on detection of radiation 30 from the stack radiation monitor (hard-wired interlock – this is the same as process 31 interlock 11, as listed in Appendix 2C). 32 33
• Supply fan K1-5-1 is interlocked to shut down upon detected increasing pressure in the 34 pump room by pressure switch PDSL-K1-304. When the system is starting up, the 35 supply fan will not start until the pressure condition is met (hard-wired interlock). 36 37
• Supply fan damper K1-FD-1-3 is interlocked to close if both exhaust fans off, or if any 38 duct smoke detector is activated (hard-wired interlock). 39 40
• Supply fan K1-5-1 shuts down upon the activation of any duct smoke detector. This 41 interlock may be bypassed by the use of a hand switch bypass (hard-wired interlock). 42 43
• Temperature controllers TIC-K1-403 and TIC-K1-407 are interlocked to only allow 44 heaters to operate when either exhaust fan (K1-5-3 or K1-5-2) is running and if air flow is 45 detected in the supply duct by FIC-K1-201 (software interlock). 46
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1 • If a High High temperature above 160°F is detected in the Condenser Room exhaust duct 2
at High High Temperature Switch (TSHH-K1-410) the 242A fire alarm control panel will 3 trip causing: (1) K22 in K1-ENCL-301 to de-energize; (2) Supply fan K1-5-1 to shut 4 down and the running exhaust fan RPM to be set to a lower speed and flow rate to 5 maintain the pump room pressure negative and Condenser Room; and (3) High High 6 Duct Temperature Alarm (TAHH-K1-410) to be sent to the VCS. 7 8
• If a High High Differential Pressure of 8-in. w.g. or greater is detected across HEPA filter 9 bank K1-6-3, limit alarm (PDSHH-K1-307) located in K1-ENCL-301 will trip and latch 10 causing: (1) Supply fan K1-5-1 to shut down; (2) a High High Differential Pressure 11 Alarm to be sent to the VCS; (3) running exhaust fan RPM to be set to a lower speed and 12 flow rate; and (4) High High Differential Pressure Light PDAHH-K1-320 on 13 K1-ENCL-301 to be illuminated. 14 15
• If a High High Differential Pressure of 8-in. w.g. or greater is detected across HEPA filter 16 bank, K1-6-2 limit alarm (PDSHH-K1-310) located in K1-ENCL-301 will trip and latch 17 causing: (1) Supply fan K1-5-1 to shut down; (2) a High High Differential Pressure 18 Alarm to be sent to the VCS (3) running exhaust fan RPM to be set to a lower speed and 19 flow rate; and (4) High High Differential Pressure Light PDAHH-K1-320 on 20 K1-ENCL-301 to be illuminated. 21 22
• If a High High Differential Pressure of 8-in. w.g. or greater is detected across HEPA filter 23 bank, K1-6-1 limit alarm (PDSHH-K1-313) located in K1-ENCL-301 will trip and latch 24 causing: (1) Supply fan K1-5-1 to shut down; (2) a High High Differential Pressure 25 Alarm to be sent to the VCS; (3) running exhaust fan RPM to be set to a lower speed and 26 flow rate; and (4) High High Differential Pressure Light PDAHH-K1-320 on 27 K1-ENCL-301 to be illuminated. 28
29 K2 System Interlocks: 30 31
• Exhaust fans K2-5-2 and K2-5-3 are shut down by HMI alarms YXA-K2-354 and 32 YXA-K2-351, respectively when the VCS output reaches 100%, and the fan speed set 33 point is not reached after 10 minutes to ensure that areas served by the K2 system remain 34 at positive pressure relative to areas served by K1. 35 36
• Loss of positive pressure as detected in the survey room, AMU room, or at the K2-5-3 37 roof exhauster shuts down K2 system exhaust fans, to maintain positive pressure. 38 Pressure in the survey room is detected by pressure switch PDSL-K2-351. Pressure in 39 the AMU room is detected by pressure switch PDSL-K2-354. Pressure at the roof 40 exhauster is detected by PDS-K2-353 (VCS software interlock). 41 42
• Supply fan K2-5-1 shuts down upon the activation of any duct smoke detector. This 43 interlock may be bypassed by the use of a hand switch bypass (hard-wired interlock). 44 45
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• All K2 system heater controllers are interlocked to only allow heaters to operate when 1 supply fan K2-5-1 is running and if air flow is detected in the supply duct by FIC-K2-251 2 (software interlock). 3
4 5 2.5.10 Analytical Sampling 6 7 The candidate feed tanks, slurry stream, and effluent streams need to be sampled to ensure the 8 242-A Evaporator operates within applicable process and safety limits. Various sampling 9 methods and systems are used, depending on the specific sampling requirements of each stream. 10 11 2.5.10.1 Sampling Requirements. Samples of underground storage tank contents scheduled 12 for use in a 242-A Evaporator campaign are required to verify that the waste is acceptable feed 13 for the 242-A Evaporator. 14 15 Samples are taken and analyzed before the tank contents are transferred to the feed tank and 16 before they are pumped from the feed tank to the 242-A Evaporator. The sampling and analysis 17 requirements for the 242-A Evaporator are established in HNF-SD-WM-DQO-014. 18 19 Data quality objectives identify the rationale and analyses required on the samples taken from the 20 underground storage tanks scheduled for processing or candidate feed tanks. The analyses 21 performed include the following: 22 23
29 DST waste contains organic material that can undergo exothermic reactions when heated to the 30 operating temperatures in the 242-A Evaporator. Therefore, the evaporator feed is analyzed 31 using a differential scanning calorimeter to ensure that incompatible wastes are not processed 32 through the 242-A Evaporator. 33 34 The inorganic constituents for each candidate feed tank are analyzed and the results consolidated 35 to characterize the feed stream. The characterization is used to provide instruction for the 36 boildown analysis, to forecast the inorganic and solids concentrations in the slurry product for 37 DST waste compatibility, and to verify ammonia concentration levels. The inorganic 38 compounds of concern are discussed in the data quality objectives (HNF-SD-WM-DQO-014). 39 40 Organic constituents in candidate feed tanks are analyzed to estimate both vessel vent organic 41 discharges and concentrations in liquids discharged to LERF. A surface sample is taken from 42 each of the candidate feed tanks and the 242-A Evaporator feed stream to look for separable 43 organics. 44 45
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A “boildown” analysis of the 242-A Evaporator feed (or consolidated candidate feed tank 1 wastes) is performed to determine the characteristics of the waste during processing. The 2 boildown analysis involves compositing samples from the candidate feed tank, concentrating the 3 composite sample by boiling, and analyzing the concentrated solution. In the case of multiple 4 feed candidates, a combined boildown or separate boildown may be performed. The laboratory 5 boildown approximates the evaporation process at the 242-A Evaporator, and the 242-A 6 Evaporator operating target is chosen based on the results of the boildown, previous processing 7 experience, and operational objectives. The solids volumes produced at various stages of the 8 boildown are used to project final DST slurry conditions. 9 10 Each of the candidate feed tanks is analyzed for radionuclides and consolidated into a 11 representative feed stream. The radionuclide feed concentrations are used to forecast the 12 radionuclide concentrations in the slurry and process condensate streams for evaluation against 13 source term and criticality safety requirements. This evaluation ensures the 242-A Evaporator 14 will not exceed the analyzed safety envelope and the subsequent limits and will not exceed the 15 LERF inventory control (HNF-SD-WM-SAD-040). 16 17 The feed radionuclide concentration is also evaluated to ensure the nuclear criticality limits for 18 the 242-A Evaporator and the receiver tanks is not violated. 19 20 Concentrated slurry could create radiation fields that exceed shielding design criteria, potentially 21 exposing facility workers in occupied areas of the 242-A Building. The 242-A Evaporator 22 shielding is designed to reduce radiation levels to < 1 mrem/h in office rooms and minimize 23 radiation levels in other areas (WHC-SD-SQA-ANAL-20001, MCNPH Calculated Gamma Dose 24 at the 242-A Evaporator Building, and WHC-SD-SQA-ANAL-20002, Calculated Gamma 25 Radiation at 242-A Evaporator’s Area Radiation Monitors and Gamma Contour Plots at 26 Selected Elevations) when the 137Cs concentration in the process liquid is < 1.5 Ci/L. Analysis 27 of candidate feed tank waste is used to forecast 137Cs concentration in the slurry product to 28 confirm that it will be below 1.5 Ci/L. A limit of 0.8 Ci/L 137Cs in process liquids has been 29 established for ALARA purposes. 30 31 2.5.10.2 Sampling Systems. Tank farms are responsible for all in-tank samples taken to 32 support 242-A Evaporator operations. Supernatant samples are taken by tank farms for liquids 33 and solids analysis prior to each 242-A Evaporator campaign, and the results are transmitted 34 formally to 242-A Evaporator engineering personnel for use in developing the process control 35 plan. Slurry and process condensate samples might be taken during a campaign to verify the 36 constituents are within limits and that concentrations are as expected. 37 38 2.5.10.2.1 Process Control Slurry Samples. The samples are taken at the slurry sample 39 enclosure by 242-A Evaporator personnel and are a means of verifying the product specific 40 gravity and percent solids, and to help characterize the slurry product. The analyses performed 41 on each sample is determined by 242-A Evaporator personnel based on campaign needs and can 42 include but are not limited to plutonium content, specific gravity, percent solids, total organic 43 compounds, aluminum, sodium, nitrate, and ammonia. 44 45
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Slurry samples are taken by remotely extracting a small portion of each stream using an Isolok 1 sampling device. The sampler extracts flow directly into sample bottles (typically 60-mL 2 plastic). The samples are subsequently loaded into lead shielding casks and transferred to the 3 laboratory for analysis. Instrument air and hot or cold water is supplied to the sample enclosure 4 to operate the Isolok sampler and to flush the sample lines. 5 6 A 3-in. recirculation bypass loop connects recirculation pump nozzle A with the pump discharge 7 nozzle B and is routed into the sample enclosure located in the load-out and hot-equipment 8 storage room. Samples of 242-A Evaporator slurry within the loop are taken in the sample 9 enclosure using slurry sampler SAMP-F-2. 10 11 2.5.10.2.2 Process Effluent Sampling. Steam condensate, cooling water, process condensate, 12 the vessel ventilation effluent, and the 242-A Building exhaust effluents are monitored and 13 sampled as described below and in Section 2.6. 14 15 2.5.10.2.3 Steam Condensate Radiation Monitoring and Sampling System (RC-1). Steam 16 condensate from the 242-A Evaporator is normally discharged to TEDF, but can be diverted to 17 the feed tank (Figure 2-21). The steam is monitored continuously by radiation detection 18 instruments and sampled by grab sampling techniques for laboratory analysis. 19 20 A continuous sample from steam condensate weir box TK-C-103 passes through a sample cooler 21 to reduce the condensate temperature and is then pumped by P-RC-1 through radiation monitor 22 RI-RC1-1, a rotameter, and pH and conductivity meters. The sample flow steam is returned to 23 steam condensate weir boxTK-C-103. 24 25 Radiation monitor RI-RC1-1 activates interlock 25 when high radiation is detected and the steam 26 condensate is automatically diverted from TEDF to the supernatant feed tank. The sample flow 27 can be diverted to bypass radiation cell and radiation element RE-RC1-1 and the cell can then 28 be drained to obtain a background radiation reading. The radiation cell is flushed if the 29 background level is increasing. High radiation alarms are annunciated and displayed on the 30 MCS in the control room. 31 32 The steam condensate is grab sampled to meet the requirement of the TEDF ICD 33 (RPP-RPT-59117). 34 35 2.5.10.2.4 Cooling Water Radiation Monitoring and Sampling System (RC-2). Used raw 36 water from the primary and after condensers is discharged to the 200 Area TEDF Pump Station. 37 The stream is monitored continuously by radiation detection instruments and sampled by grab or 38 proportional sample techniques for laboratory analysis (Figure 2-22). A small proportional 39 sample of the flow is routed through radiation monitor RC-2 and a pH and conductivity meter. 40 The sample stream then is returned to the main line. 41 42 Radiation monitor RC-2 activates interlock 29 if high radiation is detected and inhibits the RC-2 43 draining and flushing sequence. The sample flow can be diverted to bypass radiation cell 44 RE-RC-2-1 and the cell drained to check the radiation background reading. The radiation cell 45 can be flushed if the background level is increasing. A high radiation reading on the cooling 46
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water stream is not anticipated, and this stream cannot be diverted. If the stream were to become 1 contaminated, a plant shutdown would be required. High radiation alarms are annunciated and 2 displayed on the MCS in the control room. 3 4 Samples from the used raw water system are taken by grab sampling from a hose connection in 5 the raw water proportional sample line. 6 7 2.5.10.2.5 Process Condensate Radiation Monitoring and Sampling System (RC-3). 8 Process condensate from the 242-A Evaporator is discharged to LERF via process condensate 9 tank TK-C-100 (Figure 2-15). The stream is monitored continuously by radiation detection 10 instruments and sampled by grab or proportional sampling techniques for laboratory analysis. 11 A portion of the discharge stream is routed through radiation monitoring and diversion system 12 RC-3. RC-3 is similar in design and operation to the RC-1 and RC-2 systems described 13 previously. There are no pH or conductivity meters on this stream. The sample stream is routed 14 to process condensate tank TK-C-100 after passing through RC-3. Condensate flow can be 15 diverted to allow radiation cell RE-RC3-1 to drain to provide a check of the radiation 16 background. The radiation cell can be flushed if the background level is increasing. Radiation 17 readings above a specified level activate interlock 5, which under normal valve configurations 18 automatically diverts the process condensate to the feed tank 241-AW-102. 19 20 Because the process condensate is considered a mixed waste, i.e., consisting of radioactive and 21 dangerous waste, it must be routed to the LERF and stored for processing at the ETF. During 22 normal operations, the RC-3 monitoring and diversion system is used to ensure this stream is 23 within specified limits of radioactivity. The concentrations of NH3 and organics in the process 24 condensate are estimated based on candidate feed tank sampling; therefore, no routine sampling 25 of process condensate is necessary. Characterization sampling of the process condensate for 26 processing at ETF might be performed at the 242-A Evaporator or at LERF. 27 28 If high radiation is detected by the R–C-3 radiation monitor, the process condensate is diverted to 29 feed tank 241-AW-102 or process condensate tank TK-C-100. 30 31 2.5.10.2.6 Vessel Vent Stack. The vessel ventilation system is discussed in Section 2.6.1.4. 32 33 2.5.10.3 Laboratory Analytical Facilities. Candidate feed tank and slurry samples are taken 34 to the 222-S Analytical Laboratory in the 200 West Area, or to another laboratory capable of 35 handling highly radioactive samples. Samples are transported to the laboratory in a shielded 36 container called a sample pig. 37 38 Samples of the steam condensate, cooling water, and process condensate are taken for analysis to 39 the Waste Sample Characterization Facility (WSCF), or to another laboratory capable of 40 handling samples containing low concentrations of radioactive material. The samples are 41 analyzed to verify the waste streams meet TEDF and LERF acceptance requirements. 42 43 44
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2.5.11 Product Handling 1 2 The 242-A Evaporator product, concentrated liquid waste (slurry), is transferred to large 3 underground DSTs. The transfer system consists of slurry pump P-B-2 (not required when slurry 4 is transferred by gravity), internal piping, and the tank farm transfer system, which routes the 5 slurry to the designated receiver DST. Section 2.5 contains a discussion of slurry pump P-B-2, 6 its design features, instrumentation, and control systems. A description of the underground 7 transfer pipe lines and tank farm support facilities, including the safety analysis, is contained in 8 RPP-13033. 9 10 11 2.5.12 Facility Safety Criteria and Assurance 12 13 The following features provide personnel and environmental protection from radiological 14 contamination and exposure to radiation. These features also ensure that future facility 15 construction, operation, and maintenance comply with requirements. 16 The facility equipment is located in limited access areas of the 242-A Evaporator facility. 17 These areas have area monitoring systems and alarms installed to warn personnel when 18 conditions exceed established setpoints. Personnel are trained to leave the area when an area 19 radiation alarm sounds, contact the RCTs and the RCT manager, contact the building manager, 20 and wait just outside the affected area for a radiation survey. These actions help maintain 21 personnel exposure to radiation and radioactive materials ALARA. 22 23 Exposure of maintenance personnel to radiological and chemical hazards occurs primarily from 24 the pump and evaporator room equipment and is reduced to ALARA by flushing and chemical 25 decontamination of process equipment and piping, washdown and decontamination of external 26 equipment surfaces and room walls, and disposal of flush and decontamination effluents to the 27 feed tank. Personnel do not enter these rooms when waste is in the C-A-1 vessel or in the 28 recirculation loop. 29 30 Extensive radiation monitoring and process control instrumentation are provided to indicate 31 abnormal process conditions and to protect personnel and the environment. Radiation 32 monitoring systems initiate local alarms and alarms on the MCS. Process alarms initiate local 33 alarms and MCS alarms. The limits set for each alarm identify a commitment to action by 34 responders. The alarm setpoints provide time to respond and correct abnormal situations before 35 a requirement is exceeded. Process alarms are beyond normal process operations and controls. 36 37 38 2.5.13 Process Shutdown 39 40 The evaporation process can be halted at any time. This section discusses shutdown of the 41 process and is not directly related to the mode definitions of the technical safety requirements. 42 43 Heat generation rates from radioactive decay and hydrogen generation rates from radiolytic 44 decomposition are not affected by a shutdown mode. All solution transfers into and out of the 45 242-A Evaporator are suspended during shutdown. 46
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1 2.5.13.1 Short-Term Shutdown. Short-term shutdown is the continuation of all activities 2 required to maintain the recirculation processes while minor repairs are completed or failed parts 3 are replaced. Steam to the reboiler is shut down and feed and slurry flows might be suspended 4 for a few hours to a few days. All systems are operable and can be restarted as soon as the failed 5 part is repaired. The contents of the C-A-1 vessel would not be drained unless the failed part 6 was part of the C-A-1 vessel recirculation system or the slurry pumping operations or unless 7 directed by plant management. 8 9 Careful monitoring of the C-A-1 vessel temperature, pressure, and vacuum and recirculation 10 pump P-B-1 temperature, vibration, and operating amperes when the 242-A Evaporator is in 11 short-term shutdown is required to ensure the C-A-1 vessel solution is neither concentrating nor 12 diluting. The pump amperage, motor confirm signal, and two flow indicators (recirculation 13 flowmeter and recirculation bypass flowmeter) show that the recirculation pump is operating. 14 The primary indication of changing slurry concentration is a change in slurry density, which is 15 monitored by vessel dip tubes. An alternate indication would be changing liquid level in the 16 C-A-1 vessel, which also would be indicated by dip tube measurements. Finally, increasing 17 slurry viscosity would be indicated by a slow increase in the pump amperage; slurry dilution 18 would be indicated by a decrease in the pump amperage. Slurry concentration is also indicated 19 by a slow rise in the slurry density; a decrease in density indicates the solution is being diluted. 20 C-A-1 vessel liquid level indicators can be used to indicate concentration when the feed and 21 slurry pumps are not operating. A decreasing level indicates concentration and an increasing 22 level indicates dilution. 23 24 Operators are trained to maintain a constant C-A-1 vessel liquid level by adding water through 25 the de-entrainment pad flush valves or HV-CA1-2 valve (pot flush mode) when slurry is being 26 recirculated. Over concentration of the solution could lead to the formation of a thick solution 27 that could solidify and plug the pipelines, vessel, or reboiler. Over concentration of the C-A-1 28 vessel solution is prevented by turning off steam to the reboiler. 29 30 The 242-A Evaporator can be placed in short-term shutdown in < 1 hr. The primary steps are as 31 follows: 32 33
• Shut off the feed; 34 • Shut down the slurry pump P-B-2; 35 • Flush out the slurry line with water; 36 • Turn off the reboiler steam; 37 • Shut down the vacuum jets (optional); and 38 • Turn off the demister pad water sprays. 39
40 When the C-A-1 vessel is in short-term shutdown, the vacuum to the vessel may be left on, or 41 taken off. If the vacuum is left on, flammable gasses generated in the waste will be removed by 42 the eductors and the vessel vent system. If the vacuum is taken off and the purge air system 43 fails, flammable gas accumulation within the C-A-1 vessel will begin. Vacuum must be restored 44 or the vessel emptied within a certain period to avoid high concentrations of flammable gas in 45 the C-A-1 vessel headspace. 46
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1 Recirculation pump P-B-1 continues to operate and recirculate solution in the C-A-1 vessel. The 2 solution in the 242-A Evaporator can remain in the circulating configuration, if required, and the 3 temperature will rise slowly because recirculation pump P-B-1 is adding heat to the solution. 4 Once the problem is corrected, startup can be accomplished in a few hours because the solution 5 in the C-A-1 vessel is already at or very near the desired slurry concentration. Plant startup from 6 a short-term shutdown requires a reversal of the shutdown steps. This procedure takes longer 7 than shutting down the facility because the vessel vacuum must be reestablished and equilibrium 8 operation requires adjusting the feed, slurry, and steam flows. 9 10 During temporary shut downs, the SIS controls described in Section 2.5.9.2 continue to monitor 11 the process for high level and flammable gas conditions, and if necessary safely shut down the 12 process and dump the contents of the C-A-1 vessel. 13 14 2.5.13.2 Extended Shutdown. Extended shutdown is designed to minimize human exposure 15 to hazardous material and radiation doses to onsite or offsite personnel, protect the environment, 16 and protect 242-A Evaporator equipment. An extended shutdown of the two primary systems 17 (the 242-A Evaporator system and vapor condensation and treatment system) requires cessation 18 of feed processing. An extended shutdown requires that radioactive solutions be drained from 19 the C-A-1 vessel, recirculation loop, and associated piping, followed by water flushes. Feed and 20 product solutions may be drained to the feed tank or pumped to a slurry receiver tank. Steam to 21 the process is shut down and cooling water flow is minimized or stopped. 22 23 The tanks and vessels in contact with water are stainless steel, and can remain shut down for 24 extended periods without significant corrosion and require very little operator surveillance. The 25 primary surveillance would be monitoring liquid levels and temperatures in accordance with 26 approved procedures. Temperature increases or hydrogen gas generation from corrosion are 27 insignificant. Radioactive material releases are minimized by the low source term remaining in 28 the 242-A Evaporator. 29 30 The 242-A Evaporator can be placed in extended shutdown configuration in as little as 12 hr (the 31 time needed to drain feed from the C-A-1 vessel and refill it with water) or as much as several 32 weeks if either the pump room or evaporator room must be decontaminated. 33 34 2.5.13.3 Emergency Shutdown. Emergency shutdown for the 242-A Evaporator means 35 dumping the C-A-1 vessel contents into feed tank 241-AW-102. Emergency shutdown can occur 36 automatically from activation of either of the SIS controls (Section 2.5.9.2), use of the seismic 37 emergency stop button (safety interlock #S3) (Section 2.5.9.5.1), or interlock 2. The dump 38 valves automatically open and drain the C-A-1 vessel contents into the feed tank if recirculation 39 pump P-B-1 is not restarted or the timer is not bypassed before the specified time has elapsed. 40 41 Five conditions automatically shut down P-B-1 recirculation pump: 42 43
• Low seal water flow to recirculation pump P-B-1; 44 • Low liquid level in the C-A-1 vessel; 45 • Low seal water pressure to recirculation pump P-B-1; 46
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• High recirculation pump P-B-1 amperage; and 1 • Loss of normal power. 2
3 Operators are trained to shut down recirculation pump P-B-1 and dump the C-A-1 vessel when 4 excessive vibration of recirculation pump P-B-1 is detected, when a large leak in either the pump 5 room or evaporator room occurs, or during a plant emergency such as a fire, loss of power, or 6 major equipment failure. The primary focus of entry into emergency shutdown is to discharge 7 the C-A-1 vessel contents back to the feed tank to prevent over concentration or to minimize the 8 spread of contamination during a major equipment failure or line break. A 10-in. drain line can 9 be used to dump the C-A-1 vessel. Operator actions stop all flows into and out of the C-A-1 10 vessel, shut down the reboiler steam supply, and switch the bottom dump device to “dump.” 11 This opens two dump valves and the C-A-1 vessel contents rapidly drain into the feed tank. The 12 emergency shutdown actions drain most of the radioactive/hazardous material back to the feed 13 tank and allow operations to shut down the remainder of the facility in an orderly manner. A 14 deep flush of the C-A-1 vessel is normally started to remove the remaining residual activity. 15 16 Over concentration of the 242-A Evaporator contents yields higher viscosities, higher densities, 17 and higher boiling temperatures as the slurry becomes more concentrated. Three indicators of 18 increasing concentration are increasing vessel temperature, increasing slurry density, and 19 increasing recirculation pump P-B-1 amperage. A secondary indicator is excessive pressure in 20 the slurry discharge line. A high pressure in the slurry discharge line automatically alarms and 21 shuts off slurry pump P-B-2. Processing instructions in the process control plan specify the 22 maximum allowed values for the temperature and density indicators. The values are 23 conservatively set below those that would cause the slurry to become unpumpable or 24 undrainable. The large volume in the C-A-1 vessel prohibits rapid changes in density, viscosity, 25 or temperature and makes over concentration highly unlikely. 26 27 Emergency shutdown is designed to minimize radiation doses to personnel, minimize personnel 28 exposure to hazardous materials, protect the environment, and minimize equipment damage. 29 The initiating event can be failure of the recirculation pump P-B-1, a large leak in the C-A-1 30 vessel recirculation system, a natural disaster such as an earthquake or tornado, a building fire, or 31 a process system failure such as a plugged slurry line or high recirculation pump P-B-1 32 amperage. Any or all of the other equipment associated with the 242-A Evaporator, including 33 the C-A-1 vessel and building ventilation systems, could remain operational. 34 35 A 242-A Evaporator emergency dump could overcome the feed tank ventilation system. The 36 feed tank operates at approximately -2.3 in. w.g. during normal tank farm and 242-A Evaporator 37 operations. Feed tank pressure has risen to atmospheric or slightly above atmospheric 38 (approximately 1 in. w.g.) during past emergency dumps; however, the pressurizations did not 39 cause a release of contamination to the tank farm or affect tank farm personnel. RPP-13033 40 indicates that an emergency dump of the 242-A Evaporator has been analyzed and was 41 determined to present limited risk. 42 43 44
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2.5.14 Remote and Contact Maintenance Techniques 1 2 Maintenance activities are conducted in accordance with procedures and with the goal of keeping 3 all radiation doses to personnel ALARA. All maintenance activities are preplanned, monitored, 4 and evaluated. 5 6 Nearly all work done in the pump room is accomplished using remote tools and the overhead 7 crane with the goal of keeping all radiation doses to personnel ALARA. All maintenance 8 activities are preplanned, monitored, and evaluated. 9 10 RCTs monitor all activities to define, communicate, and document radiological conditions and 11 ALARA principles are used at all times and include using temporary shielding where needed. A 12 242-A Evaporator supervisor is available to assist with and make final decisions regarding using 13 remote tools and work methods to ensure radiation doses to personnel are ALARA. An ALARA 14 management worksheet and a special radiation work permit must be prepared when radiological 15 conditions meet the requirements in HNF-5183, Tank Farms Radiological Control Manual. The 16 operating contractor policies are discussed in Chapter 7.0. Lead-shielded windows are used to 17 remotely operate/observe jumper and equipment replacement and removal operations in the 18 pump room. 19 20 One ALARA concept used at the 242-A Evaporator is to replace rather than repair contaminated 21 equipment. Failed pumps are removed, placed in burial boxes, transported to the solid waste 22 burial trenches for disposal, and new pumps are installed. This approach eliminates the need for 23 contact maintenance and its associated personnel dose. Spare pumps are available so that failed 24 pumps can be replaced in an efficient and cost-effective manner. 25 26 The bag-in-bag-out technique is used to replace failed filters. The old filter is drawn into a 27 plastic bag, sealed, and cut free. The new filter is placed in the filter housing without exposing 28 personnel to airborne radioactive particulate material. 29 30 31 2.6 CONFINEMENT SYSTEMS 32 33 This section identifies and describes the set of SSCs that perform confinement functions. 34 The C-A-1 vessel and its associated piping and equipment within the facility provide primary 35 confinement of the 242-A Evaporator feed and slurry. The process condensate collection 36 system, including the condensers, piping, and collection tank, provides primary confinement for 37 the process condensate. The steam condensate system provides primary confinement of the 38 steam condensate and secondary confinement of 242-A Evaporator slurry if a leak develops in 39 the reboiler. The 242-A Building structure and its ventilation systems provide secondary 40 confinement for liquids and airborne particulate released to the building. 41 42 43
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2.6.1 Building Ventilation 1 2 The 242-A Evaporator is serviced by two primary and two secondary ventilation systems. The 3 two primary systems are designated K1 and K2. The K1 system maintains contaminated areas of 4 the facility at a negative pressure (relative to atmospheric) and filters exhaust air through two 5 stages of HEPA filtration. The K2 system maintains non-contaminated areas of the facility at a 6 positive pressure (relative to atmospheric) and exhausts or vents air directly to the environment. 7 Two secondary systems provide conditioned air to the office area and the control room for 8 personnel comfort. 9 10 2.6.1.1 K1 Ventilation System. The K1 system services the following contaminated or 11 potentially contaminated areas: 12 13
• Evaporator room; 14 • Pump room; 15 • Load-out and hot-equipment storage room; 16 • Condenser room; 17 • Ion exchange room; and 18 • Loading room. 19
20 The K1 system supply fan, K1-5-1, supplies a maximum of 17,200 ft3/min of outside air. 21 In-leakage around the loading room roll-up door accounts for additional air. The flow 22 distribution to the rooms is shown in Figure 2-23. Air supplied to occupied or potentially 23 occupied areas (i.e., condenser room, load-out and hot-equipment storage room, and loading 24 room) passes through cooling and reheating coils for personnel comfort. 25 26 Negative air pressures maintained in K1-serviced areas are shown in Figure 2-24. Air is drawn 27 through one or two parallel two-stage HEPA filter trains and discharged through stack 28 296-A-21A by exhaust fan K1-5-3 or K1-5-2. Electric fan K1-5-2 automatically starts to 29 maintain negative air pressure differentials if fan K1-5-3 fails or loses power. K1-5-2 is powered 30 from MCC-2, which is energized from the backup diesel generator upon loss of normal power. 31 The exhaust fans, HEPA filters, 296-A-21A stack, and sampling and monitoring system, are 32 located on a 49 ft-1 in. by 43-ft. 10 in. concrete HVAC equipment pad northwest of the 242-A 33 Building (Figures 2-25 and 2-26). The filter housings are constructed of sheet metal. Four 34 underground ducts, 8, 18, 24, and 30 in. in diameter, run from the facility to the HVAC 35 equipment pad where they enter a common header. One shut-off damper at the inlets and outlets 36 of each HEPA filter train permit the banks to be operated independently, if necessary, and any 37 two of the three HEPA filter trains can be used with either exhaust fan. 38 39 2.6.1.1.1 Major Components and Operating Characteristics. The primary components of the 40 K1 ventilation system are listed below and shown in Figure 2-27. 41 42
• Supply fan K1-5-1 43 • Preheat coil K1-2-1 44 • Prefilter K1-7-1 45 • Final filter K1-11-1 46
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• Cooling coil K1-3-1 1 • Reheat coils K1-4-1 and K1-4-7 2 • Electric heater HTR-K1-4-2 3 • Prefilters K1-15-1, K1-15-2, and K1-15-3 4 • HEPA filters K1-6-1, K1-6-2, K1-6-3, K1-6-4, K1-6-5, and K1-6-6 5 • Exhaust fans K1-5-2 and K1-5-3 6 • Evaporator room recirculation fan K1-9-1 7
8 Supply fan K1-5-1, located in the HVAC room, is a VFD-controlled 900 kJ/min (20 hp) 9 centrifugal fan. It draws a maximum of 17,200 ft3/min of outside air through preheat coil 10 K1-2-1, prefilter K1-7-1, and 90 to 95% final filter K1-11-1. 11 12 Preheat coil K1-2-1 is a 270 kW electric heater. The preheat coil is sufficient to raise 13 17,200 ft3/min of air by 50°F. A 104 kW heater coil, HTR-K1-4-2, downstream of the supply 14 fan, is used to provide an additional 19°F of heating to the main air flow. 15 16 Supply air flow rate is controlled by a flow controller, as measured by flow indicator/controller 17 FIC-K1-201. An inlet damper on the supply fan K1-5-1 is used to ensure that the supply fan is 18 only allowing air to pass when the exhaust fans (K1-5-3 or K1-5-2) are running, when the air 19 temperature is not freezing, and when no fires are detected in the 242-A Evaporator. 20 21 Approximately 60% of the air supplied by fan K1-5-1 is routed through chilled water air cooling 22 coil K1-3-1. 23 24 This cooling coil is used to provide cooling to the condenser room, the loading room, and the 25 load-out and hot-equipment storage room. A mixture of chilled water and coolant is provided by 26 an air cooled 302,000 kcal/hr (100 ton) nominal capacity packaged chiller, located outside of the 27 242-A Evaporator on the north side of the control room. The chilled water system is shared with 28 the K2 ventilation system, and is described in Section 2.6.1.3. 29 30 Two other reheat coils (K1-4-1 and K1-4-7), located upstream of the loading room, are used to 31 raise the temperature of the loading room during operations when the loading door is opened. 32 The reheat coil K1-4-1 is a 9 kW heater and can be used to raise the temperature of the air an 33 additional 36°F when needed. Reheat coil K1-4-7 is a 2.3 kW heater which will raise the air 34 temperature to the loading room an additional 9°F. 35 36 Pressure in the condenser room is controlled by a pressure-controlled damper PDV-K1-303. A 37 rotation limiter is installed to ensure that this damper does not close completely and allow too 38 high an air flow to the evaporator room and pump room. 39 40 Recirculation fan K1-9-1 is a turbine fan with a rating of 2,200 ft3/min. Fan K1-9-1 is located in 41 the evaporator room and is controlled by a manual “ON-OFF” switch from the control room. 42 The purpose of this fan is to draw air from the ceiling of the evaporator room and discharge it 43 near the floor. This is accomplished by a vertical 18-in. duct that runs 8 ft. from the floor of the 44 evaporator room (basement floor), up vertically along the west wall, to within 2 ft. of the ceiling. 45 46
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Exhaust air from the K1 system passes through two of three parallel HEPA filter trains. Each 1 train consists of a prefilter bank and two HEPA filter banks in a series. Each bank contains 2 9 filters in a 3-by-3 array. The prefilters, K1-15-1, -2, and -3, measure 24 in. by 24 in. by 2 in. 3 The HEPA filters, K1-6-1, -2, -3, 4, -5, and -6 measure 24 in. by 24 in. by 11.5 in. 4 5 Exhaust fan K1-5-3 is a centrifugal fan with a rating of 18,409 ft3/min at 16.9 in. w.g. Exhaust 6 fan K1-5-2 is a centrifugal fan with a rating of 18,409 ft3/min 16.9 in. w.g. Exhaust fan K1-5-3 7 and backup exhaust fan K1-5-2 are both controlled by VFD to control air flow and/or pressure 8 throughout the K1 rooms in the 242-A Evaporator. They are designed so that only one fan at a 9 time will run. When the fans are set for the pressure control mode, the exhaust fan speed is 10 controlled to keep the pressure in the pump room at a controlled set point. When the fans are set 11 for the flow control mode, the exhaust fan speed is controlled to keep the flow rate at the exhaust 12 stack at a constant. When the fans are set for a combined flow and pressure mode, the fan speed 13 is controlled to keep exhaust air flow at the greater of two flow rates – a rate to keep the pump 14 room pressure constant or to keep the exhaust air flow constant. 15 16 2.6.1.1.2 Safety Considerations and Controls. The K1 ventilation system performs two 17 functions: (1) maintains contaminated areas at a negative pressure relative to atmospheric 18 pressure; and (2) filters and monitors exhaust air to ensure releases of radioactive and hazardous 19 materials are within guidelines and ALARA. 20 21 Differential air pressures in contaminated areas are maintained by exhaust fan K1-5-3 or by 22 exhaust fan K1-5-2. The K1 system exhaust flow is sensed by flow element FE-1A and FE-1B 23 and transmitted by IT-K1-1-1 (Figure 2-28) to flow indicator FIC-K1-1 on the VCS. Loss of 24 power will cause a switch from fan K1-5-3 to fan K1-5-2. When the fans switch, the instrument 25 air lines connected to FDMs on K1-MOV-002 and K1-MOV-001 close the inlet damper for 26 exhaust fan K1-5-3 and open the inlet damper for exhaust fan K1-5-2. The damper on the inlet 27 of fan K1-5-3 fails closed and the damper on the inlet of K1-5-2 fails open on loss of normal 28 electrical power. 29 30 Failure of either fan to maintain a pressure of -0.11 in. w.g. in the pump room, as detected by 31 differential pressure switch PDSL-K1-304, removes power to supply fan K1-5-1. If both exhaust 32 fans shut down simultaneously the K1-5-1 supply fan would shut down. This interlock function 33 is also described in Section 2.5.9.10.5. There are no ducts or dampers between contaminated and 34 uncontaminated rooms and the K1 ventilation system is independent of the K2 ventilation 35 system. Ducts for the contaminated areas of the building connect to the K1-5-1 supply fan, 36 which connects by ducts to the outside air. Shutting down the supply fan before the 37 contaminated rooms become pressurized prevents a reversal of airflow between contaminated 38 and uncontaminated areas. 39 40 Air from contaminated areas passes through two HEPA filter trains, each containing two stages 41 of HEPA filters before being exhausted to the environment. The HEPA filters are tested before 42 installation to verify a removal efficiency of at least 99.97% for particles 0.3 µm (0.012 mil) in 43 size. HEPA filters are tested after installation to verify a removal efficiency of at least 99.95% 44 for the same size particles. In place aerosol testing is performed for each HEPA filter (54 total) 45 in each filter bank of each HEPA filter train. 46
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1 The differential pressure across both stages of HEPA filtration is monitored as shown in 2 Figure 2-29. A low differential pressure across either the first or second stage filter bank could 3 indicate a failure; conversely, a high differential pressure could indicate plugging leading to filter 4 failure. A low differential pressure annunciator sounds in the control room at a pressure of 5 0.51 cm (0.2 in.) w.g. for the first and second filter bank in each filter train. A high differential 6 pressure annunciator sounds in the control room at 10.2 cm (4.0 in.) w.g. for the first filter bank 7 in each filter train and 6.35 cm (2.5 in.) w.g. for the second filter bank in each filter train. 8 9 Stack 296-A-21A is equipped with a stack sampling and monitoring system (Figure 2-30). This 10 system withdraws two separate samples of the exhaust air. One sample is routed to a record 11 sampler where radioactive particulate material is collected on a filter medium. The medium is 12 exchanged on an established schedule, analyzed, and the results are the documented releases 13 from the 242-A Evaporator. The second sample of the air is routed to a stack continuous 14 beta-gamma monitor. 15 16 A failure of the radiation detector (e.g., loss of power to the stack monitoring system or a high 17 radiation level in the stack effluent) causes an alarm at the MCS and activates hardwired 18 interlock 11 (Sections 2.5.9.7 and 2.5.9.10.5, and Appendix 2C). A failure of the detector or a 19 detected level of 2,000 cpm beta-gamma, causes relay K1-1 to remove power to fan K1-5-3 and 20 prevent startup of fan K1-5-2. Supply fan K1-5-1 automatically shuts off when both exhaust 21 fans K1-5-3 and K1-5-2 are shut down. Other K1 ventilation system interlocks are described in 22 Section 2.5.9.10.5. 23 24 2.6.1.2 K2 Ventilation System. The K2 ventilation system services the following areas. 25 26
34 Supply fan K2-5-1 supplies a maximum of 13,010 ft3/min of outside air. Additional air is 35 recirculated from the HVAC room. The flow distribution is shown in Figure 2-31. Air is 36 exhausted directly to the atmosphere via exhaust fans, power wall ventilators, and gravity 37 dampers. 38 39 2.6.1.2.1 Major Components and Operating Characteristics. The major components of the 40 K2 ventilation system include: 41 42
• Supply fan K2-5-1; 43 • Preheat coil K2-2-1; 44 • Prefilter K2-7-1; 45 • Final filter K2-1-1; 46
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• Electric heaters HTR-K2-4-1, HTR-K2-1, HTR-K2-2, HTR-K2-3, HTR-K2-4, and 1 HTR-K2-5; 2
• Cooling coils K2-3-1; and 3 • Exhaust fans K2-5-2 and K2-5-3. 4
5 Supply fan K2-5-1, located in the HVAC room, is a VFD-controlled centrifugal fan. It draws a 6 maximum of 13,010 ft3/min of outside air and 800 ft3/min of recirculated air through preheat coil 7 K2-2-1, prefilter K2-7-1, final filter K2-1-1, and cooling coil K2-3-1. Electric heaters 8 HTR-K2-4-1, HTR-K2-1, HTR-K2-2, HTR-K2-3, HTR-K2-4, and HTR-K2-5 are located 9 downstream of fan K2-5-1, and condition air is supplied to routinely occupied portions of the 10 242-A Evaporator. 11 12 The roll-type prefilter and final filters are 4 ft. by 9 ft. Preheat coil K2-2-1 is a 193 kW electric 13 heater. The preheat coil is sufficient to raise 13,010 ft3/min of air by 47°F. Individual room air 14 heaters are used to further raise temperatures in K2 rooms for personnel comfort. 15 16 Air supplied by fan K2-5-1 is routed through chilled water air cooling coils K2-3-1. These 17 cooling coils are used to provide cooling to the K2 system rooms for personnel comfort. Coolant 18 is provided by an air cooled 302,000 kcal/hr (100 ton) nominal capacity packaged chiller, located 19 outside of the facility on the north side of the control room. The chilled water system is shared 20 with the K1 system, and is described in Section 2.6.1.3. 21 22 Air supplied to the AMU room is exhausted by fan K2-5-2. The fan capacity is 8,000 ft3/min at 23 0.6 in. w.g. Other rooms in the K2 system are ventilated through a roof exhaust fan, K2-5-3. 24 25 The intake and exhaust locations for the 242-A Evaporator are placed so that the discharges do 26 not influence the supply air. The K1 and K2 ventilation systems air supply louver is located on 27 the East side of the 242-A Evaporator at an elevation of approximately 714 ft. above mean sea 28 level. The vessel ventilation exhaust stack discharge is at an elevation of approximately 803 ft. 29 above mean sea level and is also located on the East side of the 242-A Evaporator, but the 30 exhaust elevation is approximately 89 ft. above the intake louver. Exhaust vents for the change 31 rooms are located 43 ft. northeast of the intake louver at an elevation of approximately 702 ft. 32 The K1 exhaust stack is northwest of the 242-A Building and exhausts at an elevation of 33 approximately 742 ft. above mean sea level. Both elevation and location of the air supply 34 louvers and exhaust stacks were selected to minimize influence on the supply air based on 35 prevailing winds, which blow from the southwest. 36 37 2.6.1.2.2 Safety Considerations and Controls. The K2 ventilation system was designed to 38 provide conditioned air for personnel comfort. Exhaust fans K2-5-2 and K2-5-3 are shut down 39 by HMI alarms YXA-K2-354 and YXA-K2-351, respectively, when the VCS output reaches 40 100% and the fan speed set point is not reached after 10 minutes to ensure that areas served by 41 the K2 system remain at positive pressure relative to areas served by K1. 42 43
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2.6.1.3 Chilled Water Cooler. Both the K1 and K2 building ventilation systems are cooled 1 by means of chilled water cooling coils. Coolant is a solution of 35% propylene glycol, and is 2 recirculated to the cooling coils via two single stage chilled water pumps. Coolant is recirculated 3 between the cooling coils, located in the HVAC room, and an air cooled 302,000 kcal/hr 4 (100 ton) nominal capacity packaged chiller, located outside of the 242-A Evaporator on the 5 north side of the control room. Included in the recirculation loop is a coolant storage tank 6 (TK-CHW-1) and an expansion tank (TK-CHW-2), to compensate for thermal expansion of the 7 coolant. A make-up water connection taps into the recirculation loop, as well as a propylene 8 glycol fill port, to allow filling and to allow the concentration of the coolant to be adjusted. 9 Several relief valves are included in the recirculation loop. 10 11 2.6.1.4 Vessel Ventilation System. The vessel ventilation system filters and discharges 12 noncondensable gases from the vacuum condenser system. Process condensate tank TK-C-100 13 and steam condensate weir box TK-C-103 are also vented by the vessel ventilation system. 14 15 2.6.1.4.1 Major Components and Operating Characteristics. The vessel ventilation system 16 (Figure 2-32) is located on the 30 ft-6 in. level of the condenser room. It consists of the 17 following major components: 18 19
• De-entrainment unit DU-C-1 20 • Prefilter/demister F-C-6 21 • Heater H-C-1 22 • HEPA filters F-C-5-1 and F-C-5-2 23 • Exhaust fan EX-C1 24 • Stack sampling and monitoring system 25 • Ammonia monitor 26
27 De-entrainment unit, DU-C-1, measures 16.5 in. by 14.5 in. by 7 in. It contains stainless steel 28 de-entrainment and prefilter/demister pads designed to remove moisture and large particulate 29 material from the after condenser exhaust gases. The pads are encased in a 10 gauge thick steel 30 box measuring 16 by 14 by 6-5/8 in equipped with a lower raw-water spray to permit flushes if 31 required. An overflow line located directly above the heater drains any water accumulation to a 32 27-gal seal pot, which drains to process condensate tank TK-C-100. Instrumentation is provided 33 to monitor the pressure drop across the unit. A high ∆P across the unit causes an alarm on the 34 MCS in the control room. 35 36 Prefilter/demister F-C-6 measures 16.6 in. by 14.5 in. by 7 in. thick. Liquids removed by the 37 prefilter/demister are routed to process condensate tank TK-C-100. Instrumentation is provided 38 to monitor pressure drop across the unit. A high ∆P across the unit causes an alarm on the MCS 39 in the control room. 40 41 Heater H-C-1 consists of an electric heating coil rated at 12 kW to prevent moisture from 42 accumulating on the HEPA filters. The stainless steel heater is 12 in. by 11.5 in. by 3 in. thick. 43 Airflow rates are 500 to 700 ft3/min. It is an extended surface heater used to obtain a 50°F 44 design temperature differential. The normal operating temperature delta across the heater is 45 50°F. Both high and low temperature differentials alarm on the MCS in the control room. 46
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A drain line, which is routed to a seal pot that drains to process condensate tank TK-C-100, is 1 located downstream of the heater, but it is not normally used because the higher gas temperature 2 prevents condensate formation on the HEPA filters. Instrumentation is provided to monitor the 3 inlet and outlet air temperatures for process control. A third temperature element provides a 4 signal to a temperature switch. The switch shuts off the electric power to the heating coil and 5 causes a high temperature alarm on the MCS in the control room. 6 7 HEPA filters F-C-5-1 and F-C-5-2 are steel-framed units supporting a glass fiber media. The 8 24 in. by 24 in. by 11.5 in. filters are mounted in series, and the overall dimension of each filter 9 housing is ~40⅛ by 40⅛ by 24 in. During normal operations an air bleed-in valve controls 10 differential pressures across the filters. The filter stages are monitored for both high and low ∆P 11 readings. High and low readings cause an alarm at the MCS, and high differential pressures 12 activate software interlock 4, which shuts off vessel ventilation exhauster EX-C1. High ∆P 13 across the first stage HEPA filter F-C-5-1 causes an alarm at the MCS in the control room and 14 activates hardwired interlock 4, which shuts off vessel ventilation exhauster EX-C1. 15 Exhaust fan EX-C1 has a capacity of 700 ft3/min at 10 in. w.g. Exhaust air is discharged from 16 the building via a vent pipe identified as stack 296-A-22. The stack is equipped with radiation 17 sampling and monitoring instruments. It is equipped with a stack sampling and monitoring 18 system. The system withdraws a sample of the exhaust air and splits it into two streams. One 19 portion is routed to a record sampler, where radioactive particulate material is collected on a 20 filter medium. The medium is exchanged on an established schedule, analyzed, and the results 21 are the documented releases from the 242-A Evaporator. The second portion of the air sample is 22 routed to a stack continuous beta-particulate monitor. 23 24 High NH3 concentrations in some waste feeds increase the potential for releases of NH3 gas from 25 the vessel ventilation stack. Ammonia releases from the vessel ventilation exhaust stack are 26 monitored by a continuous ammonia monitor installed on the vessel ventilation exhaust stack. 27 The ammonia monitor is operated, if necessary, based on pre-campaign sample analysis and the 28 decision is documented in the campaign process control plan and/or process control memos. 29 Detector tube sampling capability is maintained as a contingency. The ammonia monitor is 30 self-contained and withdraws gas through a 1-in. diameter stainless steel tube penetrating the 31 8-in. diameter vessel ventilation stack downstream of the vessel ventilation stack monitor. 32 The sample gas is returned to stack 296-A-22 for discharge to the atmosphere after the ammonia 33 concentration measurement is made. The ammonia concentration is continuously monitored on 34 the MCS and is hardwired to alarm in the event of high ammonia concentrations or monitor 35 failure. The CERCLA Reportable Quantity for gaseous ammonia discharge to the environment 36 is 100 lb in a 24-hr period. If the vessel ventilation ammonia monitor indicates that the ammonia 37 level might exceed 50 lb in 24-hr with no intervention, 242-A Evaporator engineering is notified 38 to trend and evaluate the discharge and provide process direction to lower the discharge level. 39 40 2.6.1.4.2 Safety Considerations and Controls. An important consideration in the design and 41 operation of the vessel ventilation system is the potential for moisture accumulation on the 42 HEPA filters, which could weaken the filter media and lead to structural failure. Deentrainer 43 DU-C-1 and prefilter/demister F-C-6 are provided to physically remove water carried over from 44 the after condenser E-C-3. Heater H-C-1 is provided to raise the temperature of the airstream 45
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above the dew point of water. At temperatures above the dew point the remaining entrained 1 water droplets undergo a phase change and pass through the filter media as a vapor. A high 2 temperature at the heater outlet causes an alarm at the MCS in the control room and activates 3 hardwired interlock 44 to shut off the heater at a temperature of 200°F. 4 5 The ∆P across each HEPA filter stage and both filter stages combined is monitored. Software 6 alarms that sound in the control room are set for high ∆P across the first filter, F-C-5-1, at 7 > 3 in. w.g. and at > 2 in. w.g. across the second filter, F-C-5-2. A combined differential 8 pressure of > 5.0 in. w.g. across both filter stages also alarms in the control room. Interlock 4 9 activates when MCS software detects high differential pressure across filters F-C-5-1 or F-C-5-2 10 or when excessive high differential pressure is detected across filters F-C-5-1 (hardwired 11 interlock). 12 13 Airborne releases of radioactive material from the vessel ventilation system are maintained 14 ALARA by passing the exhaust air through two stages of HEPA filtration. 15 16 The HEPA filters are factory tested to verify a particulate removal efficiency of 99.97 % for 17 particles 0.3 micron in size. The filters are tested at installation to verify a removal efficiency of 18 99.95% for the same size particles, and tested periodically thereafter. To detect a filter leak, or a 19 blown out filter (and therefore a potential for an unfiltered release), low differential pressure 20 switches are also installed across both filters to alarm a low differential pressure. 21 22 Stack 296-A-22 is equipped with a stack monitoring and sampling system similar in design to 23 that installed on 296-A-21A. The alarm is set at 2,000 cpm beta-gamma and upon alarm 24 activates interlock 20, which shut down vessel ventilation system exhaust fan EX-C1. 25 Interlock 20 is hardwired in addition to being controlled by the MCS. The vessel ventilation 26 stack monitoring system also contains a silver zeolite filter to sample the airstream for the 27 gaseous radioisotopes of iodine, antimony, and tin when required by the campaign process 28 control plan. 29 30 31 2.7 SAFETY SUPPORT SYSTEMS 32 33 This section identifies and describes the principal systems that perform safety support functions. 34 The purpose of each system is described and an overview of each is provided, including principal 35 components, operations, and control functions. 36 37 38 2.7.1 Fire Protection Systems 39 40 Fire protections systems for the 242-A Evaporator include fire rated barriers, water supply, 41 suppression, and sprinkler systems in accordance with NFPA requirements. 42 43
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2.7.1.1 Fire Rated Barriers. The wall separating the control room from the support area is 1 the only fire rated barrier associated with 242-A Evaporator. The wall is 0.3m (12in.) thick and 2 consists of concrete block and gypsum wall board. The wall does not extend above the roof and 3 does not serve as a parapet. The door between the control room and support area is a 3/4-hour 4 fire-rated assembly. Penetrations for cables appear adequately sealed. The duct penetration has 5 no fire damper. The fire damper is not required in a wall of 1-hour fire resistance. The fire 6 resistance rating of the composite assembly (wall, door, and penetration seals) is 1 hour. 7 8 The construction of the rest of the facility is substantial and could be considered to be fire rated due 9 to the thickness of the walls. The 242-A Evaporator process area is constructed of massive 10 reinforced concrete. The interior walls, floor slabs, and roof slabs which separate the process rooms 11 and the concrete slabs above the process rooms could be considered Type I construction. The 12 structure is of massive concrete construction, but the doors in the partitions do not have a fire 13 resistance rating and wall and ceiling penetrations are not sealed to maintain a fire resistance 14 rating. Therefore, none of the interior walls (except the south control room wall), floor slabs, or 15 roof slabs have a fire resistance rating. 16 17 Due to the maximum possible fire loss being below the $150 million and $350 million amounts 18 requiring redundant fire protection systems and dividing the facility into fire zones by 3 hour fire 19 resistance rated barriers/walls (MGT-ENG-IP-05, Fire Protection Program, Section 7a), rated 20 walls are not required. 21 22 2.7.1.2 Water Supply Adequacy and Reliability. The primary water supply system at the 23 Hanford Site is an underground main system. Redundant water supplies are provided through 24 two water system upgrade projects: B-604, which upgraded the water supply reservoir, and 25 L-005, which upgraded the 200 East Area laterals. The fire suppression systems are provided 26 with a 6-in. riser supply off the 14-in. line that supplies raw water to the 242-A Evaporator. 27 28 242-A is served by two hydrants, each with 6-in. feed mains. One hydrant is located 29 approximately 20 ft. from the east corner of the building, and the other hydrant is located 30 approximately 76 ft. from the southwest corner of the building [HNF-SD-WM-FHA-024, Fire 31 Hazards Analysis for the Evaporator Facility (242-A)]. 32 33 2.7.1.3 Fire Suppression Systems. The process area of the 242-A Evaporator is classified as 34 an Ordinary Group 2 fire hazard according to NFPA 13, Standard for the Installation of 35 Sprinkler Systems. HNF-SD-WM-FHA-024 evaluated the sprinkler system and concluded it is 36 adequate for the hazards in the condenser room. 37 38 A water flow switch is installed to monitor the flow of water in the automatic sprinkler system. 39 Manual pull stations are provided in the facility to initiate a fire alarm. 40 41 A Fire Alarm Control Unit monitors the building fire alarm system and initiates a signal to the 42 Hanford Fire Department if fire, smoke, water flow in the sprinkler system, or system malfunction 43 are detected. A local alarm bell is also sounded. The fire alarm system is described in more detail 44 in HNF-SD-WM-FHA-024. 45 46
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The installed water flow detection and alarm systems comply with requirements in DOE orders 1 and NFPA 101, Life Safety Code, Chapter 40, for this type of occupancy and personnel staffing. 2 3 2.7.1.4 Location of Sprinkler Heads. The location of sprinkler heads at the 4 242-A Evaporator have been evaluated and judged to meet the requirements of NFPA 13 5 (HNF-SD-WM-FHA-024). 6 7 8 2.7.2 Radiation Protection Systems 9 10 Radiation exposure to 242-A Evaporator personnel is controlled to well below DOE limits and is 11 ALARA. Control of radiation dose to personnel is accomplished by building design with 12 shielding walls and compartmentalization of radioactive materials (layout), HVAC systems for 13 confinement of radioactive materials, installed radiation detection and monitoring 14 instrumentation, personnel access control, and procedures. The shielding walls, building layout, 15 and ventilation systems are discussed in Sections 2.4.2, 2.4.3, and 2.6. Installed radiation 16 detection and monitoring instrumentation, personnel access control, and procedures are discussed 17 in the following paragraphs. More detailed information is presented in Chapter 7.0. 18 19 Radiation monitoring instrumentation. Two area radiation monitors are installed in the 20 condenser room, one (RIAS-AR-1) at the basement level and one (RIAS-AR-2) on the fourth 21 level. One area radiation monitor (RIAS-AR-3) is installed in the AMU room on the first level. 22 They have a range of 0.1 to 1,000 mR/h with an adjustable alarm setpoint, normally set at 23 5 mR/h above background. A radiation level above the alarm setpoint initiates a local audible 24 alarm and an alarm on the MCS in the control room. The area radiation monitors are not 25 required by the Radiation Protection Program and are used primarily for radiation background 26 information. The area radiation monitors are occasionally used to obtain supplemental process 27 control information. 28 29 A personnel contamination monitor is located in the hallway near the entrance to the condenser 30 room to monitor personnel for the presence of clothing and skin contamination following work in 31 an area of potential or known surface contamination. 32 33 Stack continuous air monitors are installed to sample the K-1 and vessel ventilation exhaust air 34 and are described in Section 2.6. 35 36 Liquid effluent monitoring systems are described in Sections 2.5.8.3 and 2.5.9.7. 37 38 A radiation work permit is required for all personnel access to radiological areas and work with 39 radioactive materials. Access to high radiation areas is only through locked, key controlled 40 doors and barriers. 41 42
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2.7.3 Fire Protection Alarms, Lights, and Signs 1 2 Fire protection system alarms, emergency lights, manual pull boxes, and exit signs are located 3 throughout the 242-A Evaporator in accordance with NFPA requirements 4 (HNF-SD-WM-FHA-024). 5 6 7 2.7.4 Communications and Alarms 8 9 An intercom system at the 242-A Evaporator provides clear, two-way voice communication with 10 an environment background noise level of 90 ±5 dB. Communication ports are located in the 11 following rooms. 12 13
24 Each communication port is capable of communicating with any other port. The ports in the 25 pump room, evaporator room, load-out and hot-equipment storage room, loading room, and 26 condenser room permit communication while the user is on respiratory protection. 27 28 The intercommunication system is operable except during loss of electrical power. Backup 29 communication systems, telephone and battery operated two-way hand-held radios, operate 30 during loss of electrical power. In addition, the small size of the 242-A Evaporator allows 31 adequate voice communication. 32 33 34 2.8 UTILITY DISTRIBUTION SYSTEMS 35 36 This section provides a schematic outline of the basic utility distribution systems, including a 37 description of the offsite power supplies and onsite components of the system. Details of 38 systems are given for understanding the utility distribution philosophy and facility operation. 39 40 41 2.8.1 Electrical 42 43 Normal electrical power is provided to the Hanford Site by the Bonneville Power 44 Administration. 230-kV power is reduced to 13.8 kV at the 251W substation and distributed to 45
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the 200 East and 200 West areas. 13.8 kV power is supplied from the substation via aerial lines 1 to a 1500 kVA substation located just east of the 242-A Evaporator. 2 3 This substation converts the 13.8 kV primary feed to 480/277-V power for all equipment within 4 the 242-A Building, and the 242-A-81 Raw Water Supply Building. 5 6 Backup power is supplied by a 200 kW (268 hp) diesel generator and a UPS. The generator and 7 associated switchgear automatically supply power to Motor Control Center 2 within 1 min of 8 loss of normal power. (Note: The diesel generator and transfer switch are not required to be 9 available during evaporator operations). 10 11 The UPS supplies power to panel board F, which supplies the control room including the MCS 12 and the VCS. Motor Control Center 2 provides power to the following equipment and services 13 (including panel board F). 14 15
• Vessel vent exhauster EX-C-1; 16 • K1 ventilation backup fan K1-5-2; 17 • Air compressors CP-E-1 and CP-E-2; 18 • K1 ventilation stack monitoring system; 19 • Control room HVAC Unit AC-001; 20 • Panel board C; 21 • Fire alarm panel; 22 • Emergency lights; 23 • Instrument panels; 24 • Control circuits; 25 • Alarm circuits; 26 • Panel board E; 27 • Condenser room ammonia monitor; 28 • Vessel ventilation stack monitoring systems; 29 • Control room lighting; 30 • Computer shunt trip circuit; and 31 • Panel board F (Control room [UPS]). 32
33 A one-line electrical diagram of the backup power supply is shown in Figure 2-33. Fuel for the 34 generator is stored in an adjacent underground 550-gal, double-wall fiberglass reinforced plastic 35 tank equipped with leak, high liquid level, and overflow detection that alarms at the tank location 36 and at the MCS. The local alarms are individual and sound at the backup generator site and the 37 MCS alarm is a common alarm. 38 39 The control room UPS provides power to the MCS to facilitate process monitoring on loss of 40 power. During normal operation the electrical load is placed directly on a continuously 41 recharged battery pack. On loss of power the sealed lead acid gel-cell battery pack supplies 42 power to the control room and MCS for a minimum of 22 min. The UPS provides sufficient 43 time for the backup power to be supplied or to monitor the dump of the C-A-1 vessel into the 44 feed tank upon complete loss of power. 45 46
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1 2.8.2 Steam 2 3 Steam is supplied to the 242-A Evaporator from the 242A-BA boiler annex. The 242A-BA boiler 4 annex contains one 200 hp medium pressure (150 lb/in2 gauge) boiler and two 700 hp low 5 pressure (15 lb/in2 gauge) boilers. Only one low pressure and one medium pressure boiler are 6 required for 242-A Evaporator operation. There is one dedicated backup 700 hp boiler for the 7 low pressure system. The boilers produce steam used to serve the following principal functions. 8 9
• Reboiler heat supply – 10 lbf/in2 gauge. 10 • Steam jet ejectors for the vacuum condenser system – 90 lbf/in.2 gauge. 11
12 Steam also operates the jet gang valve system used for transferring liquid from the pump room 13 sump to feed tank 241-AW-102. 14
15 2.8.2.1 Reboiler Heat Supply. A principal function of the steam system is to heat process 16 slurry to the temperature required for evaporation. Steam at 10 lbf/in2 gauge is supplied to the 17 242-A Evaporator from the 242A-BA boiler annex. 18 19 A total of 15 interlocks affect the supply of steam to the reboiler. Six of these are hardwired, and 20 the remainder are controlled by the MCS. A description of the interlocks is provided in 21 Section 2.5.9 and in Appendix 2C. 22 23 2.8.2.2 Vacuum Condenser Steam Jet Ejectors. Steam is used by the steam jet ejectors to 24 draw a vacuum that moves vapors from the C-A-1 vessel through the primary, inter-, and 25 after-condensers. Steam at 90 lbf/in.2 gauge is supplied to the 242-A Evaporator from the 26 242A-BA boiler annex. A 3-in. diameter line supplies the steam to steam jet ejectors J-EC1-1 27 and J-EC1-2. Condensate is removed from the steam-by-steam separator SS-C-1 before the 28 steam enters the ejectors. Interlock 39 controls the steam supply to J-EC1-1 and J-EC2-1. 29 If vacuum break valve HV-EC1-1 opens to break the condenser, vacuum interlock 39 closes 30 valve HV-EC2/EC3-1 to shut off the steam supply to the jet ejectors. 31 32 2.8.2.3 Safety Considerations and Controls. The 242A-BA boiler annex for the 242-A 33 Evaporator has one 200 hp medium pressure (150 lb/in2 gauge) boiler and two 700 hp low 34 pressure (15 lb/in2 gauge) boilers. The medium pressure boiler is for steam heat and various 35 process systems in the 242-A Evaporator. There is no backup medium pressure boiler. 36 Connections are in place that allow a portable medium pressure boiler to be connected if needed. 37 The low pressure steam system has a primary and backup boiler available. The low pressure 38 boiler(s) feed the 242-A Evaporator reboiler with 10 lb/in2 gauge steam. In the event of a 39 primary boiler failure, either the backup boiler can be brought online or a temporary boiler can 40 be connected to the system (either on the low pressure or the medium pressure system). If a 41 boiler failure occurs and no temporary/backup boiler is available, then the plant casualty plan for 42 loss of steam outlines emergency actions to be taken. The vacuum source for the 43 242-A Evaporator will be lost, steam flow to the reboiler will stop, and the 242-A Evaporator 44 vacuum will slowly return to atmospheric pressure, preventing further boiling of the vessel 45 contents. 46
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1 2 2.8.3 Water 3 4 Three water services are required for the 242-A Evaporator: raw water, filtered raw water, and 5 sanitary water. Raw water is pumped from the 282-EC Building to the 242-A Evaporator via a 6 14-in. water main. The principal process function of the raw water system is to provide 7 condenser cooling. The raw water system also supplies water to the fire protection sprinkler 8 system and to the filtered raw water system. Provisions are required for adequate system 9 pressure, redundancy, system over-pressurization, and backflow prevention. 10 11 Filtered raw water is used primarily as seal water for process pumps and for spraying down the 12 C-A-1 vessel de-entrainment pads. Provisions are required for adequate system pressure, 13 over-pressurization, and backflow prevention. 14 15 Sanitary water provides service to the lunchroom and change rooms and is supplied separate 16 from the raw water system. 17 18 Although the raw water and sanitary water systems are separate systems in the 242-A 19 Evaporator, there is a cross-tie (with backflow preventers) between the systems in the 282-EC 20 Building (i.e., between the raw water and potable [sanitary] water systems). Upon a reduction in 21 raw water system pressure, potable (sanitary) water will flow through the backflow preventers to 22 supplement the raw water system. A detailed description of the water supply is given in the 23 following sections. 24 25 2.8.3.1 Raw Water System. The raw water system supplies cooling water to condensers 26 E-C-1 and E-C-2 for the condensation of 242-A Evaporator overheads. The used cooling water 27 from condenser E-C-2 is routed to condenser E-C-3. Functions include the following: 28 29
• Supplying water for 242-A Evaporator process makeup; 30 31
• Initiating 242-A Evaporator startup and shutdown; 32 33
• Cooling the process air; 34 35
• Flushing the vessel ventilation de-entrainment pads; 36 37
• Cooling steam condensate; 38 39
• Supplying hose connections and spray nozzles for decontamination purposes; 40 41
• Maintaining the pump room sump at the proper level; 42 43
• Maintaining the proper level in the seal pot; 44 45
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• Supplying water for the makeup of inhibited water (water treated with hydroxide and/or 1 nitrite, used for corrosion control tank [flushes] of tank farm transfer lines); 2 3
• Flushing the product slurry lines and 242-A Evaporator dump line; 4 5
• Supplying water for the filtered raw water system; and 6 7
• Supplying water for the fire protection system. 8 9
The raw water system is supplied from the Columbia River via the 282-EC Building. A 14-in. 10 pipeline runs from the 282-EC Building to the 242-A-81 Water Services Building located south 11 of the 242-A Evaporator. The building is a pre-engineered structure measuring 28 ft. by 20 ft. by 12 10 ft. high constructed under Project B-534. The floor is a 6-in. thick concrete slab sloped to a 13 3 ft. by 3 ft. by 3 ft. central sump pit. The sump drains to TEDF. The water use during a 14 campaign is approximately 3,600 gal/min. 15 16 2.8.3.1.1 Major Components and Operating Characteristics. The 14-in. raw water line 17 branches into two identical parallel 10-in. lines (Figure 2-34), each containing the following 18 components: 19 20
• Gate valves, HV-RW-27 and HV-RW-31; 21 • Strainers, F-RW-1 and F-RW-2; 22 • Pressure Control Valves, PCV-RW-1, PCV-RW-1A, PCV-RW-2, and PCV-RW-2A; and 23 • Backflow Preventers, BFP-RW-1 and BFP-RW-2 with Gate Valves HV-RW-20 and 24
HV-RW-40. 25 26 The two lines rejoin into a 14-in. line that exits the building, enters the 242-A Building in the 27 AMU room, and travels through the 242-A building to the condenser room. 28 29 Gate valves HV-RW-27 and HV-RW-31 are used to isolate the raw water flow to the two 30 filtering system branches. If a raw water branch requires maintenance, the corresponding gate 31 valve is closed; otherwise they are always fully open. 32 33 The pressure control valves are a two-stage control configuration. The 3-in. diameter pressure 34 control valves (PCV-WR-1A and PCV-RW-2A) control the pressure at low flow rates. The 35 10-in. pressure control valves (PCV-RW-1 and PCV-RW-2) control pressure at high flow rates. 36 37 The strainers F-RW-1 and F-RW-2 are rated for flows in excess of 2,000 gal/min. The 38 differential pressure across the strainers is monitored by the MCS. The strainer is backwashed to 39 the sump when a high-pressure differential is detected. 40 41 The backflow prevention devices BFP-RW-1 and BFP-RW-2 prevent backflow from the 42 downstream process connections in accordance with State of Washington requirements for 43 cross-connection control. Each unit consists of a reduced pressure backflow preventer mounted 44 between two manually operated gate valves. Drain lines direct water escaping from the 45 backflow preventers to the building sump. Flow through the individual branches is controlled by 46
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the backflow preventer downstream gate valves, HV-RW-20 and HV-RW-40. The gate valves 1 are either full open for full flow or closed. 2 3 The pressure relief valves PSV-RW-1 and PSV-RW-2 prevent over-pressurization of the entire 4 raw water system. The pressure relief valves are located upstream of HV-RW-27 and 5 HV-RW-31 and are sized such that one pressure relief valve can provide adequate protection. 6 The pressure relief valves discharge to the building sump. 7 8 2.8.3.1.2 Safety Considerations and Controls. The differential pressure across the strainers is 9 monitored and an alarm is sounded in the control room when a high differential pressure 10 condition is detected. The drain lines from BFP-RW-1 and BFP-RW-2 are equipped with leak 11 detectors that alarm in the control room. The liquid level in the sump is monitored, and a 12 low-level condition alarms in the control room. Maintaining a minimum liquid level in the sump 13 prevents vapors from the TEDF discharge line from entering the 242-A-81 Building. 14 15 There is no backup source of raw water for the 242-A Evaporator. RPP-27867, Building 16 Emergency Plan for 242-A Evaporator, outlines emergency action that must be taken in the 17 event of a critical raw water outage. The seal water source for the 242-A Evaporator 18 recirculating and slurry pumps might be lost and the evaporator vacuum condensers will not 19 function. Assuming the seal water is not recycled process condensate, recirculation pump P-B-1 20 and slurry pump P-B-2 will shut down on loss of raw water supply to the filtered raw water 21 system. After a specified period following shutdown of recirculation pump P-B-1, the C-A-1 22 vessel will be dumped automatically to feed tank 241-AW-102. The vacuum in the C-A-1 vessel 23 will slowly return to atmospheric pressure, preventing further boiling of the vessel contents. The 24 fire protection system will be inoperative without raw water. The emergency plan also outlines 25 action required to shut down the 242-A Evaporator. 26 27 2.8.3.2 Filtered Raw Water and Process Condensate Recycle System. The filtered raw 28 water and process condensate recycle system is used for the following purposes: 29 30
• Upper and lower de-entrainment pads spray (filtered raw water and process condensate 31 recycle); 32 33
• Wash down of the C-A-1 vessel above the liquid level (filtered raw water and process 34 condensate recycle); 35 36
• Seal water for recirculation pump P-B-1 and slurry pump P-B-2 (filtered raw water and 37 process condensate recycle); 38 39
• Makeup and flush water for the antifoam tank, TK-E-102 (filtered raw water only); 40 41
• 242-A Evaporator weight-factor water drip system (filtered raw water only, currently 42 disconnected); and 43 44
• Vessel Vent Ammonia monitor (filtered raw water only). 45 46
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2.8.3.2.1 Major Components and Operating Characteristics. The filtered water system 1 (Figure 2-35) is supplied from the raw water supply and the process condensate recycle system is 2 supplied from process condensate tank TK-C-100. These systems consist of the following major 3 components: 4 5
• Filters F-H-1, F-H-2, and F-H-3 (filtered raw water only) 6 7
• Upper de-entrainment pad spray microfilter (F-CA1-1) (filtered raw water or process 8 condensate recycle) 9 10
• Filters F-C-4 and F-C-5 (process condensate recycle) 11 12
• Filters F-CA1-L and F-CA1-R (filtered raw water or process condensate recycle) 15 16
• Pumps P-C-105 and P-C-105A (filtered raw water or process condensate recycle). 17 18 A 1.5-in. line from the main 14-in. raw water supply header supplies water to filter F-H-3. The 19 line branches from F-H-3 to supply filters F-H-1 and F-H-2. These filters are arranged in 20 parallel. One filter is used while the other is in standby. The differential pressure across the 21 filters is monitored to detect pluggage or failure. 22 23 Filtered raw water from filters F-H-1 and F-H-2 is supplied directly to the antifoam tank. 24 Filtered raw water for the lower and upper de-entrainment pad sprays and seal water for 25 recirculation pump P-B-1 and slurry pump P-B-2 is routed through three-way control valve 26 HV-CA1-10. Process condensate recycle is also supplied to HV-CA1-10. This valve is used to 27 control whether filtered raw water or process condensate is to be used for the deentrainer pad 28 sprays and seal water. Additional filtering is required before use for the upper de-entrainment 29 pad sprays or as seal water. Water is passed through microfilter F-CA-1 to minimize sediment, 30 which increases the efficiency of the de-entrainment pad sprays. Seal water passes through 31 parallel filters F-CA1-L and F-CA1-R to remove particles > 0.4 microns prior to use to extend 32 both pump and seal life. 33 34 Process condensate supplied from process condensate tank TK-C-100 can be recycled for use as 35 lower and upper de-entrainment sprays and as seal water for recirculation pump P-B-1 and slurry 36 pump P-B-2. A 2-in. line from TK-C-100 nozzle K on condensate collection tank process 37 condensate tank TK-C-100 supplies process condensate to condensate recycle pump P-C-106. 38 The line branches from the pump to supply filters F-C-4 and F-C-5. These filters are arranged in 39 parallel and one filter is used while the other is in standby. 40 41 The differential pressure across the filters is monitored to detect pluggage or failure. Filtered 42 process condensate is routed to HV-CA1-10 for use as described above. 43 44 Seal water pumps P-C-105 and P-C-105A are located in the condenser room (50 ft-6 in. level) 45 and provide filtered raw water to recirculation pump P-B-1 and slurry pump P-B-2 respectively. 46
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1 2.8.3.2.2 Safety Considerations and Controls. A backflow preventer, check valves, and flow 2 control valves control the filtered raw water system. Backflow preventer BFP-CA1-1 protects 3 the raw water supply from backflow of potentially contaminated water. Double check valves are 4 installed on each of the eight filtered raw water lines to C-A-1 vessel de-entrainment pad sprays 5 and double check valves are installed on the filtered raw water lines to recirculation pump P-B-1 6 and slurry pump P-B-2 seals. A single check valve is installed on the discharge lines from 7 pumps P-C-105 and P-C-105A. 8 9 There is an identified potential for a waste backflow event from the slurry sampling system to the 10 AMU room where workers could come in contact with the waste. Backflow preventer 11 BFP-RW-11, located on this water line in the hot equipment storage room, is installed to prevent 12 this backflow event. 13 14 There is an identified potential for waste back-siphoning from the dip tube flushing system, the 15 slurry flush line, and from the dump flush line back to the condenser room and the AMU room 16 where workers could come in contact with the waste. Backflow preventer PSV-RW-3, located 17 on the fifth floor of the condenser room, is installed to prevent this backflow event. 18 19 Recirculation pump P-B-1 seal water is maintained at a higher pressure than the process solution 20 so that process solution cannot leak into the seal. Slurry pump P-B-2 is a centrifugal pump with 21 impeller balance holes that allow the slurry discharge pressure to be higher than the seal water 22 pressure. RPP-TE-52377, P-B-2 Pump Seal Water Pressure Analysis, calculates the maximum 23 slurry pump P-B-2 discharge pressure so that process solution cannot leak into the seal. Also, a 24 loss of seal water pressure could result in seal damage. Process condensate recycle system 25 pressure is monitored by pressure indicator PI-CA1-20 and interlocked to reposition control 26 valve HV-CA1-10 from process condensate to filtered raw water if the pressure falls below a 27 preset value. Pressure indicator PI-CA1-9 is interlocked (interlock 21) to shut off recirculation 28 pump P-B-1 if the seal water pressure falls below a preset value. Similarly, pressure indicator 29 PI-CA1-10 is interlocked (interlock 23) to shut off slurry pump P-B-2 if the water seal pressure 30 falls below a preset value. A pressure relief valve opens at 830 kPa (120 lbf/in2 gauge) to protect 31 the pump seals from over pressurization. The valve drains to process condensate 32 tank TK-C-100. 33 34 The seal water flow rate is monitored by flow indicator FI-CA1-1 and interlocked (interlock 13) 35 to shut down recirculation pump P-B-1 if the flow rate falls below a preset value. Similarly, 36 FI-CA1-2 is interlocked (interlock 22) to shut down slurry pump P-B-2 if flow falls below a 37 preset value. 38 39 The seal water pumps are not connected to the backup power supply and will shut down on loss 40 of power. Loss of power also shuts down recirculation pump P-B-1 and slurry pump P-B-2, and 41 C-A-1 vessel contents are drained to the feed tank to prevent damage to the pump seals. 42 43 Both the low seal water flow interlocks and the low seal water pressure interlocks for 44 recirculation pump P-B-1 and slurry pump P-B-2 alarm in the control room and shut down the 45
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pumps. Shutdown of recirculation pump P-B-1 results in a complete shutdown of the 242-A 1 Evaporator by interlock 2. 2 3 2.8.3.3 Sanitary Water System. Sanitary water is provided to the lunchroom, drinking 4 fountains, change rooms, safety showers, K1 and K2 ventilation system air washers, and backup 5 cooling for the air compressors. 6 7 8 2.8.4 Compressed Air System 9 10 The compressed air system consists of the following major components: 11 12
• Air compressors CP-E-1 and CP-E-2 and 13 • Air receiver tank R-E-1. 14
15 2.8.4.1 Air Compressors (CP-E-1 and CP-E-2). Compressors CP-E-1 and CP-E-2 are 16 rotary screw type air compressors installed in parallel, with one compressor on-line and the other 17 on standby. The standby unit is operated only if the on-line compressor fails or if the operating 18 pressure falls below a preset limit. The compressors can be operated on backup power if normal 19 power fails. 20 21 The skid mounted screw type air compressors are designed to deliver a minimum of 100 ft3/min 22 at 100 lbf/in.2 gauge. The air compressors are cooled utilizing integral air-to-oil heat exchangers. 23 As an option for summer operation, supplemental cooling can be provided using an optional 24 glycol-to-oil heat exchanger on each unit. The glycol cooling fluid is provided by chillers 25 located outside of the 242-A Evaporator. Each air compressor skid is also equipped with an air 26 dryer. 27 28 2.8.4.2 After-Cooler (E-E-6). After cooler E-E-6 is not-in-service. 29 30 2.8.4.3 Air Receiver Tank (R-E-1). Air receiver tank R-E-1 is an upright steel tank 15–ft. 31 high with a volume of 125 ft3. It is equipped with an access port, a pressure relief valve set at 32 125 lbf/in2 gauge, a pressure gauge, a moisture trap, and a drain valve. 33 34 2.8.4.4 Compressed Air Distribution. Process air is routed from the air receiver to various 35 locations within the 242-A Evaporator. Its principal use is to operate or control air-actuated 36 valves and to pressurize the reboiler (Table 2-4). 37 38 Instrument air is used primarily by process control instrumentation (e.g., specific gravity/WF 39 tubes). 40 41 2.8.4.5 Safety Considerations and Controls. Only one air compressor is required to 42 operate during normal and abnormal conditions so that loss of one compressor does not cause a 43 loss of compressed air. The SIS described in Section 2.5.9.2 are designed to fail safe upon loss 44 of process/instrument air. 45 46
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The two compressors are powered from MCC-2 (see Section 2.8.1). MCC-2 is a 400 A bus and 1 has two power sources: (1) normal power from the 1500 kVA substation, and (2) the backup 2 200 kW diesel generator. The diesel generator starts automatically and transfers power to 3 MCC-2 from a transfer switch in the generator enclosure on loss of normal power to the 4 400 A bus. Electrical power is designated a general services system at the 242-A Evaporator and 5 the backup diesel generator and transfer switch are not required to be available during evaporator 6 operations. 7 8 Connections for portable air compressor tie-in are provided on the south side of the 242-A 9 Building. 10 11 The compressed air system includes two air accumulators, 242AEI-IA-ACC-001 and 12 242AEI-IA-ACC-002, installed in series to ensure an adequate supply of air is available to 13 cycle steam valve HV-EA1-5. The air compressors protect the temperature rating of solenoid 14 HY-EA1-5 by ensuring the compressed air has time to cool ambient temperatures. 15 16 Piston-operated valves at the 242-A Evaporator have inline oilers for lubrication, and use of 17 process air for operation is acceptable. 18 19 20 2.8.5 Maintenance Systems 21 22 A remotely operated bridge crane services the pump room, load-out and hot-equipment storage 23 room, and loading room. The crane is used for removing and moving contaminated equipment 24 from the pump room to the load-out and hot-equipment storage room with essentially no 25 exposure of personnel to ionizing radiation. Decontamination work is performed as needed for 26 transport once the contaminated equipment is in the load-out and hot-equipment storage room. 27 Equipment maintenance and repair are also performed. 28 29 Safety features for the pump room crane include: (1) a crane retrieval system (assuming loss of 30 power or crane failure) capable of moving the crane (with a two-ton load) to the south extremity 31 of the crane rails for repair; (2) automatic braking of the hoists during loss of power to prevent 32 rapid descent of loads; (3) travel speed limited to less than 39.4 in./min; and (4) limit switches 33 for the hoists to prevent run-out of the hoist cable and collision with the crane support structure. 34 In addition, various preventive maintenance inspections and tests are performed routinely by 35 plant personnel and there are third party inspections. 36 37 Loss of crane function, regardless of the cause, has no significant impact on safety at the 38 242-A Evaporator. 242-A Evaporator operations are shut down during maintenance activities in 39 the pump room. This configuration minimizes the potential for leaks of radioactive solution to 40 the pump room in the event of a crane accident, such as a suspended load impacting piping or 41 jumpers. 42 43 The hoists are operated from viewing windows in the AMU room. The operating stations are 44 interlocked to allow only one station to be used at a time. 45 46 Access to the crane maintenance platform, located at the south end of the crane gallery above the 47 loading room, is through an airlock at the top of the stairs from the AMU room mezzanine. 48
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1 2 2.9 AUXILIARY SYSTEMS AND SUPPORT FACILITIES 3 4 This section provides information on the remaining portions of the 242-A Evaporator that have 5 not been covered by the preceding sections and that are necessary to create a conceptual model 6 of the 242-A Evaporator as it pertains to the hazard and accident analyses. 7 8 9 2.9.1 222-S Laboratory 10 11 Slurry samples taken from the 242-A Evaporator are transported, using approved shipping 12 containers and trucks, to the 222-S Laboratory facilities in the 200 West Area, where they are 13 analyzed or prepared for shipment to other laboratories for analysis. 14
2.9.2 Waste Sample Characterization Facility (WSCF) 15 16 Samples of the process condensate, steam condensate, and the used raw water are transported to 17 the WSCF where they are analyzed or prepared for shipment to other laboratories for analysis. 18 The WSCF is an analytical laboratory for nonradioactive and low-level radioactive sample 19 analysis. It is located in the 600 Area, just east of the 200 West Area. Samples may also be 20 shipped to 222-S or off-site facilities if necessary for analysis. 21 22 23 2.9.3 Tank Farms 24 25 Feed material for the 242-A Evaporator is staged in the feed tank 241-AW-102, which is a 26 1 million-gal DST. 242-A Evaporator feed is pumped from the feed tank to the 27 242-A Evaporator via an underground-encased pipeline. Miscellaneous solutions are returned to 28 the feed tank via three underground drain lines (two of which are encased) that run from the 29 242-A Building to the tank drain pit. 242-A Evaporator slurry product is pumped from the 30 242-A Evaporator to a valve pit via underground-encased piping. From the valve pit, the slurry 31 can be directed to a specific DST. Figure 2-2 shows the general location of the piping runs. 32 33 34 2.9.4 242A-BA Steam Supply 35 36 Steam required for the evaporation process is supplied to the 242-A Building via a 12-in. steam 37 line for 10 lbf/in2 gauge (low pressure) steam and a 6-in. steam line for the 90 lbf/in2 gauge 38 (medium pressure) steam from the 242A-BA boiler annex. The 242A-BA boiler annex contains 39 one 200 hp medium pressure (150 lb/in2 gauge) boiler and two 700 hp low pressure 40 (15 lb/in2 gauge) boilers. 41 42 Fuel oil for the package boilers is supplied from a 40,000-gal tank located approximately 174 ft. 43 southwest of 242-A Evaporator on the west side of 242-A Building. If the tank were to be 44 breached by a vehicle collision, any material released would flow away from the 45
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242-A Evaporator due to ground slope. The consequences of a large fire involving the tank were 1 evaluated in HNF-SD-WM-FHA-024. The analysis concluded that the primary impact to the 2 242-A Evaporator was that soot from the fire could be drawn into the 242-A Building and, given 3 sufficient time, might plug the K-1 exhaust filters. 4 5 6 2.10 PORTABLE HEATERS 7 8 Portable propane, diesel, and oil fuel fired heaters are sometimes used at the 242-A Evaporator 9 for personnel comfort. Hanford Fire Marshal Permits describe the conditions for use (e.g., type 10 and number of heaters allowed, capacity and number of refueling containers allowed, location of 11 heaters and refueling containers). 12 13 14 2.11 REFERENCES 15 16 10 CFR 830, “Nuclear Safety Management,” Code of Federal Regulations. 17 18 40 CFR 264, “Standards for Owners and Operators of Hazardous Waste Treatment, Storage, and 19
Disposal Facilities,” Code of Federal Regulations. 20 21 ANSI/ISA-84.00.01-2004 series, “Functional Safety: Safety Instrumented Systems for the Process 22
Industry Sector.” 23 24 ASCE 7-05, Minimum Design Loads for Buildings and Other Structures, American Society of Civil 25
Engineers, Reston, Virginia. 26 27 ASME, 2004, Quality Assurance Requirements for Nuclear Facility Applications, NQA-1, American 28
Society of Mechanical Engineers, New York, New York. 29 30 CERCLA, 1980, Comprehensive Environmental Response, Compensation and Liability Act of 1980, 31
42 U.S.C. 9601, et seq. 32 33 DOE 435.1-1, 1999, Radioactive Waste Management Manual, Administrative Change 2, 34
U.S. Department of Energy – Office of Environmental Management, Washington, D.C. 35 36 DOE/EP-0108, 1984, Standard for Fire Protection of DOE Electronic Computer/Data Processing 37
System, U.S. Department of Energy, Washington, D.C. 38 39 DOE G 421.1-2, 2001, Implementation Guide for Use in Developing Documented Safety Analyses to 40
Meet Subpart B of 10 CFR 830, U.S. Department of Energy – Office of Environmental 41 Management, Washington, D.C. 42
43 DOE O 458.1, 2011, Radiation Protection of the Public and the Environment, Change Notice No. 2, 44
U.S. Department of Energy, Washington, D.C. 45 46
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DOE/RL-89-10, Hanford Federal Facility Agreement and Consent Order, as amended, Washington 1 State Department of Ecology, U.S. Environmental Protection Agency, U.S. Department of 2 Energy, Olympia, Washington. 3
Rev. 1, Appendix 3E, U.S. Department of Energy-Richland Operations Office, Richland, 6 Washington. 7
8 DOE/RL-2001-36, Hanford Sitewide Transportation Safety Document, as amended, U.S. Department 9
of Energy, Richland Operations Office, Richland, Washington. 10 11 DOE-STD-1020-2016, 2016, Natural Phenomena Hazards Analysis and Design Criteria for DOE 12
Facilities, U.S. Department of Energy, Washington, D.C. 13 14 DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor Nuclear 15
Facility Documented Safety Analysis, Change Notice No. 3, U.S. Department of Energy, 16 Washington, D.C. 17
Portion, Revision 8C, for the Treatment, Storage, and Disposal of Dangerous Waste, 20 WA7890008967, as amended, State of Washington, Department of Ecology, Kennewick, 21 Washington. 22
23 Foster, J., 2017, “Interface Agreement between 242-A and Liquid Effluent Retention Facility; 24
Conversion of HNF-3395 Rev 6. 7//272017,” (interoffice memorandum WRPS-1703509 to 25 B. Johnson, D. Vasquez, July 27), Washington River Protection Solutions LLC, Richland, 26 Washington. 27
28 HNF-2905, 1998, 1998 242-A Interim Evaporator Tank System Integrity Assessment Report, Rev. 0, 29
Lockheed Martin Hanford Company, Richland, Washington. 30 31 HNF-3327, 1998, 242-A Evaporator Life Extension Study, Rev. 0, Waste Management Federal 32
Services, Inc., Richland, Washington. 33 34 HNF-3327, 2001, Engineering Study for the 242-A Life Extension Upgrades for Fiscal Years 2002 35
Thru 2005, Rev. 1, Waste Management Hanford, Richland, Washington. 36 37 HNF-5183, Tank Farms Radiological Control Manual, as amended, Washington River Protection 38
Rev. 2, Fluor Hanford, Richland, Washington. 42 43 HNF-SD-WM-DQO-014, 2009, 242-A Evaporator Data Quality Objectives, Rev. 7, Washington 44
River Protection Solutions LLC, Richland, Washington. 45 46
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HNF-SD-WM-FHA-024, 2017, Fire Hazards Analysis for the Evaporator Facility (242-A), Rev. 8C, 1 Washington River Protection Solutions LLC, Richland, Washington. 2
3 HNF-SD-WM-OCD-015, Tank Farms Waste Transfer Compatibility Program, as amended 4
Washington River Protection Solutions LLC, Richland, Washington. 5 6 HNF-SD-WM-SAD-040, 2001, Liquid Effluent Retention Facility Final Hazard Category 7
Determination, Rev. 2, Fluor Hanford, Richland, Washington. 8 9 IBC, 2009, International Building Code, International Code Council, Inc., Country Club Hills, 10
Illinois. 11 12 MGT-ENG-IP-05, 2016, Fire Protection Program, Rev. 3, U.S. Department of Energy, Office of 13
River Protection, Richland, Washington. 14 15 NFPA 13, 1996, Standard for the Installation of Sprinkler Systems, National Fire Protection 16
Association, Quincy, Massachusetts. 17 18 NFPA 101, 1997, Life Safety Code, National Fire Protection Association, Quincy, Massachusetts. 19 20 NFPA 220, 1999, Standards for Types of Building Construction, National Fire Protection Association, 21
Quincy, Massachusetts. 22 23 Resource Conservation and Recovery Act of 1976, 42 U.S.C. 6901, et seq. 24 25 RPP-8949, 2002, Project Execution Plan for 242-A Evaporator Life Extension Upgrades, Rev. 0, 26
CH2M HILL Hanford Group, Inc., Richland, Washington. 27 28 RPP-13033, Tank Farms Documented Safety Analysis, as amended, Washington River Protection 29
Solutions LLC, Richland, Washington. 30 31 RPP-15810, Enveloping Tank Farm Transfer Pump Power, Discharge Head, and Flow, as amended, 32
Washington River Protection Solutions LLC, Richland, Washington. 33 34 RPP-27867, Building Emergency Plan for 242-A Evaporator, as amended, Washington River 35
Washington River Protection Solutions LLC, Richland, Washington. 39 40 RPP-RPT-33306, 2008, IQRPE Integrity Assessment Report for the 242-A Evaporator Tank System, 41
Phenomena Hazards, Rev. 0, Washington River Protection Solutions LLC, Richland, 45 Washington. 46
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1 RPP-RPT-53035, 2015, 242-A Evaporator C-A-1 Vessel Seismic Dump System – Functions and 2
Requirements Evaluation Document, Rev. 4, Washington River Protection Solutions LLC, 3 Richland, Washington. 4
5 RPP-RPT-54583, 2017, Design Analysis Report for the 242-A Evaporator C-A-1 Vessel Flammable 6
Gas Control System, Rev. 7, Washington River Protection Solutions LLC, Richland, 7 Washington. 8
9 RPP-RPT-54584, 2015, Design Analysis Report for the 242-A Evaporator C-A-1 Vessel Waste High 10
Level Control System, Rev. 5, Washington River Protection Solutions LLC, Richland, 11 Washington. 12
13 RPP-RPT-59117, 2016, 200 Area Treated Effluent Disposal Facility Interface Control Document, 14
Rev. 0, Washington River Protection Solutions LLC, Richland, Washington. 15 16 RPP-TE-52377, 2012, P-B-2 Pump Seal Water Pressure Analysis, Rev. 0, Washington River 17
2C.0 INTERLOCKS 1 2 3 2C.1 PROCESS INTERLOCKS 4 5 Interlock 1. Interlock #1 is activated when the slurry discharge flow decreases below minimum 6 acceptable rate. The interlock: 7 8
• Starts timer KY-CA1-2 for a specified time 9
• When the time-delay period has expired the following actions occur and the slurry lines 10 are flushed: 11
− P-B-2 pump is shut down 12
− HV-CA1-2 and HV-CA1-2A are placed in the 242-A Evaporator flush position; valve 13 HV-CA1-6 is opened 14
− After 30 s, valves HV-CA1-2 and HV-CA1-2A are placed in the farm flush position 15
− After KY-CA1-2F times out, HV-CA1-2 and HV-CA1-2A are placed in block 16 position 17
• If the slurry discharge flow returns to normal during the specified period, timer 18 KY-CA1-2 stops and resets. 19
• This interlock is bypassed by placing HV-CA1-2 in manual. 20 21 Interlock 2. Interlock #2 is activated when P-B-1 pump shuts down. The interlock: 22 23
• Opens air supply valve HV-EA1-3 to pressurize reboiler chest 24
• Closes valve FV-EA1-1 to reboiler. 25 26 Interlock 3. Reserved. 27 28 Interlock 4. Interlock #4 is activated when excessively high differential pressure detected on 29 filters in vessel ventilation system is detected. This interlock: 30 31
• Shuts off supernatant feed pump and associated feed block valve HV-CA1-1 32 • Closes valve FV-EA1-1 to reboiler 33 • Opens air supply valve HV-EA1-3 to pressurize reboiler chest 34 • Closes valve HV-EC2/EC3-1 to vacuum jet ejectors J-EC1-1 and J-EC1-2 35 • Opens vacuum breaker valve HV-EC1-1 36 • Shuts off vessel ventilation exhauster E-X-C1. 37
38
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Interlock 5. Interlock #5 is activated when excessive radiation level in process condensate 1 effluent to the Liquid Effluent Retention Facility (LERF) basins is detected. Either or both the 2 hardwired and software interlock(s) may be used. The interlock: 3 4
• Positions valve HV-RC3-3 to divert process condensate to tank TK-241-AW-102 5
• Prohibits RC3-1 monitor draining and flushing sequence 6
• Shuts off the condensate recycle pump P-C106 and activates Interlock #53 (Hardwired 9 interlock only. The backup software interlock does not automatically perform this 10 function.) 11
• Close feed block valve HV-CA1-1 12
• Open 18 psig air supply valve HV-EA1-3 to pressurize reboiler chest 13
• Close valve FV-EA1-1 to reboiler 14
• Shut off supernatant feed pump. 15 16 Interlock 6. Reserved. 17 18 Interlock 7. Interlock #7 activates when signals originating in tank farms indicate excessive 19 radiation level in 241-AW Tank Farm service pit. The interlock: 20 21
• Shuts off P-B-2 slurry pump. 22 23 Interlock 8. Interlock #8 is activated when excessive pressure in vessel C-A-1 vapor body is 24 detected. The interlock: 25 26
• Closes valve FV-EA1-1 to reboiler 27 • Opens air supply valve HV-EA1-3 to pressurize reboiler chest. 28
29 Interlock 9A. Interlock #9A is activated when low liquid level in process condensate tank 30 TK-C-100 is detected. The interlock: 31 32
• Shuts off agitator A-C100 33 • Shuts off the condensate recycle pump P-C106 which activates Interlock #53. 34
35 Interlock 9B. Interlock #9B is activated when low-low liquid level in process condensate tank 36 TK-C-100 is detected. The interlock: 37 38
• Shuts off P-C100 pump. 39 40
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Interlock 10. Interlock #10 is activated when excessive flow or low flow is detected in the 1 recirculation line. The interlock: 2 3
• Closes steam valve FV-EA1-1 4 • Opens air supply valve HV-EA1-3 to pressurize reboiler chest. 5
6 Interlock 11. Interlock #11 is activated when excessive radiation level in the building exhaust 7 stack is detected. The interlock: 8 9
• Shuts off building exhauster fan K1-5-3 and prevents fan K1-5-2 from operating. 10 11 Interlock 12. Interlock #12 is activated when high liquid level in vessel C-A-1 is detected. The 12 interlock: 13 14
• Shuts off supernatant feed pump P-241-AW-102 and closes associated feed block valve 15 HV-CA1-1. 16
17 Interlock 13. Interlock #13 is activated when low seal water flow to recirculation pump P-B-1 18 is detected. The interlock: 19 20
• Shuts down recirculation pump P-B-1 and activates Interlock #2. 21 22 Interlock 14. Interlock #14 is activated when excess differential pressure across lower 23 de-entrainment pad in vessel C-A-1 is detected. The interlock: 24 25
• Closes feed valve HV-CA1-1 26 • Shuts off feed pump P-241-AW-102 27 • Opens air bleed valve HV-EC1-1 and activates Interlock #39. 28
29 Interlock 15. Interlock #15 is activated when low liquid level in vessel C-A-1 is detected. The 30 interlock: 31 32
• Shuts off recirculation pump P-B-1 and activates Interlock #2 (unless PB1WFINLK is in 33 the Bypass state 34
• Shuts off slurry pump P-B-2 (unless PB2WFINKLK is in the Bypass state). 35 36 Interlock 16. Interlock #16 is activated when miscellaneous signals originating in tank farms 37 (YS-PB2-1L) are received. The interlock: 38 39
• Shuts off slurry pump P-B-2. 40 41 Interlock 17. Interlock #17 is activated when the AP Farm Master Shutdown Handswitch 42 located in the 242-A Control Room is activated. The interlock: 43 44
• Shuts off slurry pump P-B-2. 45 46
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Interlock 18. Interlock #18 is activated when excessive pressure in slurry discharge line is 1 detected. The interlock: 2 3
• Shuts down slurry pump P-B-2. 4 5 Interlock 19. Interlock #19 is activated when the supernatant feed pump is shut down. The 6 interlock: 7 8
• Shuts off feed block valve HV-CA1-1. 9 10 Interlock 20. Interlock #20 is activated when excessive radiation level in vessel ventilation 11 system is detected. The interlock: 12 13
• Shuts off supernatant feed pump and associated feed block valve HV-CA1-1 14 • Closes valve FV-EA1-1 to reboiler 15 • Opens air supply valve HV-EA1-3 to pressurize reboiler chest 16 • Closes valve HV-EC2/EC3-1 to vacuum jet ejectors J-EC1-1 and J-EC2-1 17 • Shuts off vessel ventilation exhauster fan EX-C-1 18 • Opens vacuum breaker valve HV-EC1-1. 19
20 Interlock 21. Interlock #21 is activated when low seal water pressure to recirculation pump 21 P-B-1 is detected. The interlock: 22 23
• Shuts off recirculation pump P-B-1 and activates Interlock #2. 24 25 Interlock 22. Interlock #22 is activated when low seal water flow to slurry pump P-B-2 is 26 detected. The interlock: 27 28
• Shuts off slurry pump P-B-2. 29 30 Interlock 23. Interlock #23 is activated when low seal water pressure to slurry pump P-B-2 is 31 detected. The interlock: 32 33
• Shuts off slurry pump P-B-2. 34 35 Interlock 24. Interlock #24 is activated when signals from 241-AW Tank Farm indicate 36 abnormal conditions have been detected. The interlock: 37 38
• Shuts down the supernatant feed pump and activates Interlock #19. 39
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Interlock 25. Interlock #25 is activated when excessive radiation level in steam condensate 1 effluent is detected by RC-1 sampler. The interlock: 2 3
• Positions valves HV-EA1-2 and HV-RC1-3 to divert steam condensate to supernatant 4 feed tank 5
• Closes valve FV-EA1-1 to reboiler 6
• Opens air supply valve HV-EA1-3 to pressurize reboiler chest 7
• Prohibits RC1-1 monitor draining and flushing sequence-- Valves HV-RC1-1, 8 HV-RC1-2, and HV-RC1-4 remain in the normal/failure position 9
• Interrupts flow totalizer FQI-EA1NM and activates flow totalizer FQI-EA1-D. 10 11 Interlock 26A. Interlock #26A is activated when low liquid level is detected in eluant tank 12 TK-E-101. The interlock: 13 14
• Shuts off eluant tank agitator A-E-101. 15 16 Interlock 26B. Interlock #26B is activated when low-low liquid level is detected in eluant tank 17 TK-E-101. The interlock: 18 19
• Shuts off pump P-E-101. 20 21 Interlock 27A. Interlock #27A is activated when low liquid level is detected in the antifoam 22 tank TK-E-102. The interlock: 23 24
• Shuts off anti-foam tank agitator A-E-102. 25 26 Interlock 27B. Interlock #27B is activated when low-low liquid level is detected in antifoam 27 tank TK-E-102. The interlock: 28 29
• Shuts off pump P-E-102. 30 31 Interlock 28A. Interlock #28A is activated when low liquid level is detected in decontamination 32 tank TK-E-104. The interlock: 33 34
• Shuts off decontamination tank agitator A-E-104. 35 36 Interlock 28B. Interlock #28B is activated when low-low liquid level is detected in 37 decontamination tank TK-E-104. The interlock: 38 39
• Shuts off pump P-E-104. 40 41 Interlock 29. Interlock #29 is activated when excessive radiation level is detected in used raw 42 water. The interlock: 43 44
• Prohibits RC-2 monitor draining and flushing sequence. 45
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1 Interlock 30. Reserved. 2 3 Interlock 31. Reserved. 4 5 Interlock 32. Interlock #32 is activated when miscellaneous signals originating in tank farms 6 (YS-PB2-1L) are received. The interlock: 7 8
• Shuts off slurry pump P-B-2. 9 10 Interlock 33. Reserved. 11 12 Interlock 34. Interlock #34 was part of the ion exchange system. The columns have been 13 removed from the facility and the interlock is not functional. 14 15 Interlock 35. Reserved. 16 17 Interlock 36. Reserved. 18 19 Interlock 37. Reserved. 20 21 Interlock 38. Interlock #38 is activated when excessive temperature is detected from 22 desuperheater. The interlock: 23 24
• Closes valve FV-EA1-1 to reboiler 25 • Opens air supply valve HV-EA1-3 to pressurize reboiler chest. 26
27 Interlock 39. Interlock #39 is activated when vacuum breaker valve HV-EC1-1 has opened. 28 The interlock: 29 30
• Closes valve HV-EC2/EC3-1 to vacuum jet ejectors J-EC1-1 and J-EC2-1 31 • Closes steam valve FV-EA1-1 to reboiler 32 • Opens air supply valve HV-EA1-3 to pressurize reboiler chest. 33
34 Interlock 40. Reserved. 35 36 Interlock 41. Reserved. 37 38 Interlock 42. Reserved. 39 40 Interlock 43. Interlock #43 is activated when excessive pressure is detected on process 41 condensate line filter F-C-3. The interlock: 42 43
• Shuts off process condensate pump P-C-100. 44 45
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Interlock 44. Interlock #44 is activated by low vessel ventilation stack flow or excessive vessel 1 ventilation air temperature or vessel ventilation system shutdown. The interlock: 2 3
• Shuts off H-C-1 (vessel ventilation heater). 4 5 Interlock 45. Interlock #45 is activated by High High temperature (150°F) on TE-EA-1 or 6 TE-EA1-1S located in the vapor liquid separator C-A-1 recirculation line. The interlock: 7 8
• Closes valve FV-EA1-1 (steam to reboiler). 9 10 Interlock 46. Reserved. 11 12 Interlock 47. Reserved. 13 14 Interlock 48. Reserved. 15 16 Interlock 49. Reserved. 17 18 Interlock 50. Reserved for 244-A lift station (Tank Farms). 19 20 Interlock 51. Reserved. 21 22 Interlock 52. Interlock#52 is activated by excessive differential pressure on filter F-C-5 or 23 F-C-4. The interlock: 24 25
• Shuts down pump P-C106 and activates Interlock #53. 26 27 Interlock 53. Interlock #53 is activated by recycle pump P-C106 shutdown. The interlock: 28 29
• Positions valve HV-CA1-10 to the filtered raw water supply. 30 31 Interlock 54. Interlock #54 is activated by low recycle system discharge pressure. The 32 interlock: 33 34
• Positions valve HV-CA1-10 to the filtered raw water supply. 35 36 Interlock 55. Interlock #55 is activated whenever valve FV-EA1-1 is commanded “OFF,” i.e., 37 steam off and air on. The interlock: 38 39
• Closes valve HV-EA1-4 after a time delay. 40 41 Interlock 56. Interlock #56 is activated by high pressure in C-A-1 vapor space (170 torr) as 42 sensed by PT-CA1-7. The interlock: 43 44
• Opens valve HV-CA1-20. 45 46
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Interlock 57. Interlock #57 is activated by high pressure in feed tank TK-241-AW-102. The 1 interlock: 2 3
7 Interlock 58. Interlock #58 is activated by a continuous fault condition on RC1; RXA-RC1-1 8 active fault, or open loop/short circuit detected for RI-RC1-1, or RXA-RC1-1. After a preset 9 delay (≥ 5 sec) the monitoring and control system (MCS) will automatically divert steam 10 condensate back to the supernatant feed tank via HV-RC1-3. The interlock: 11 12
• Command HV-RC1-3 to “Divert” position. 13 14 Interlock 59. Interlock #59 is activated by a continuous fault condition on RC3; RXA-RC3-1 15 active fault, or open loop/sort circuit detected for RI-RC3-1, or RXA-RC3-1. After a preset 16 delay (≥ 5 sec) the MCS will automatically divert process condensate (from LERF) back into 17 TK-C-100 via HV-RC3-3 and shut off process condensate pump P-C-100. The interlock: 18 19
• Command HV-RC3-3 to “Divert” position 20 • Command P-C-100 to STOP running. 21
22 23 2C.2 SAFETY SIGNIFICANT INTERLOCKS 24 25 Interlock S1. Interlock #S1 is activated by high differential pressure (7.5 in WG) across C-A-1 26 vessel lower de-entrainment pad (PDSHH-CA1-4) for more than 5 seconds, OR interlock #S1 is 27 activated by high sensing line air flow (2.9 SCFH) for PDT-CA1-4 (FSHH-CA1-8) for more 28 than 60 seconds, OR interlock #S1 is activated by low sensing line airflow (.8 SCFH) for 29 PDT-CA1-4 (FSLL-CA1-9) for more than 60 seconds (Vessel Level safety instrument function 30 [SIF]). The interlock: 31 32
• Initializes 30-minute time delay following the initial trip 33 • Opens vessel vacuum break valve HV-EC1-5 via solenoid valve HY-EC1-5 34 • Opens dump valve HV-CA1-1 via solenoid valve HY-CA1-1A 35 • Shuts off feed pump AW-P-102 via contactor M-PAW-102A 36 • Closes 10# steam supply valve HV-EA1-5 via solenoid valve HY-EA1-5 37 • Shuts off pump P-B-1 via contactor M-PB-1A (non SIF) 38 • Relay trip confirmed is sent to the MSC (non SIF software) 39
40 If the MCS receives relay trip confirmed signal from the SIS, the MCS will mimic S1 41 logic listed above by taking final elements to the defined safe state i.e., open HV-EC1-1 42 via HY-EC1-1 open HV-CA1-1 via HY-CA1-1, shut off feed pump AW-P-102 via 43 MCC-001 C5; the MCS will also close FV-EA1-1 via FY-EA1-1 instead of HV-EA1-5, 44 which is controlled by the SIS. 45 46
• Shuts off pump P-B-1 via STR-PB1-1. 47
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1 And Interlock #S1 is activated after the 30 minute time delay following the initial trip if initial 2 conditions are still met (REF RPP-RPT-54584, Design Analysis Report for the 242-A Evaporator 3 C-A-1 Vessel Waste High Level Control System). The interlock: 4 5
• Opens dump valve HV-CA1-7 via solenoid valve HY-CA1-7A 6 • Opens dump valve HV-CA1-9 via solenoid valve HY-CA1-9A. 7
8 Interlock S2. Interlock #S2 is activated when the following vessel pressure and purge flow 9 conditions are both met for 30 minutes: C-A-1 Vessel absolute pressure increases to 190 torr 10 (PSHH-CA1-12 or PSHH-CA1-13) AND vessel purge air flow is 3.1 SCFM FSH/FSLL-CA1-20A 11 or FSH/FSLL-CA1-20B) OR high temperature (157°F) downstream of E-A-1 reboiler for 12 5 seconds (TSHH-EA1-1 or TSHH-EA1-1S) (Flammable Gas safety instrumented function). 13 The interlock: 14 15
• Initializes 30-minute time delay following the initial trip 16 • Opens vessel vacuum break valve HV-EC1-5 via solenoid valve HY-EC1-5 (non SIF) 17 • Opens dump valve HV-CA1-1 via solenoid valve HY-CA1-1A 18 • Shuts off feed pump AW-P-102 via contactor M-PAW-102A 19 • Closes 10# steam supply valve HV-EA1-5 via solenoid valve HY-EA1-5 20 • Shuts off pump P-B-1 via contactor M-PB-1A 21 • Shuts off pump P-B-1 via contactor M-PB-1A 22 • Relay trip confirmed is sent to the MSC (non SIF software) 23
24 If the MCS receives relay trip confirmed signal from the SIS, the MCS will mimic S1 25 logic listed above by taking final elements to the defined safe state i.e., open HV-EC1-1 26 via HY-EC1-1 open HV-CA1-1 via HY-CA1-1, shut off feed pump AW-P-102 via 27 MCC-001 C5; the MCS will also close FV-EA1-1 via FY-EA1-1 instead of HV-EA1-5, 28 which is controlled by the SIS. 29 30
• Shuts off pump P-B-1 via STR-PB1-1. 31 32 And Interlock #S2 is activated after the 30 minute time delay following the initial trip if initial 33 trip conditions of pressure and purge flow are still met (REF RPP-RPT-54583, Design Analysis 34 Report for the 242-A Evaporator C-A -1 Vessel Flammable Gas Control System). The interlock: 35 36
• Opens dump valve HV-CA1-7 via solenoid valve HY-CA1-7A 37 • Opens dump valve HV-CA1-9 via solenoid valve HY-CA1-9A. 38
39
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Interlock S3. Interlock #S3 is activated when shutdown button HS-CA1-2 located near the 1 control room south door is pushed OR the seismic shutdown button HS-CA1-1 located outside 2 the south door on the east wall of the AMU room is pushed OR shutdown button HS-CA1-3 3 located near the control room east door is pushed. Computer Room MCS Shutdown function 4 bypass selector switch HS-CA1-4 located in hallway outside the AMU Room can be placed in 5 Bypass to prevent MCS shutdown function activated by pushing HS-CA1-1, HS-CA1-2, or 6 HS-CA1-3 (REF RPP-RPT-53035, 242-A Evaporator C-A-1 Vessel Seismic Dump System – 7 Functions and Requirements Evaluation Document). The interlock: 8 9
3 4 Table 3.3.1.1-1. Hazard Identification Checklist and Energy Designators .................... T3.3.1-1 5 Table 3.3.1.3-1. Frequency Ranges ................................................................................ T3.3.1-2 6 Table 3.3.1.3-2. Safety Classification Guidelines .......................................................... T3.3.1-3 7 Table 3.3.1.5-1. Safety Integrity Level Determination for Safety Instrumented 8
Systems ................................................................................................. T3.3.1-4 9 Table 3.3.2.3.2-1. Summary of Safety Structures, Systems, and Components and 10
Technical Safety Requirements for Representative Accidents. ..... T3.3.2.3.2-1 11 Table 3.3.2.3.2-2. Other Defense-In-Depth Features (Non-Safety SSCs and 12
Non-TSR Administrative Features). ............................................. T3.3.2.3.2-3 13 Table 3.3.2.3.2-3. Defense-In-Depth Features for Potential Hazardous 14
Conditions. ..................................................................................... T3.3.2.3.2-7 15 Table 3.3.2.4-1. Summary of General Technical Safety Requirements for 16
242-A Evaporator Accidents ............................................................. T3.3.2.4-1 17 Table 3.3.2.4.1-1. Summary of Frequency and Consequesnces for Flammable 18
Gas Accidents without Controls ..................................................... T3.3.2.4.1-1 19 Table 3.3.2.4.1-2. Summary of Safety Structures, Systems, and Components for 20
Flammable Gas Accidents .............................................................. T3.3.2.4.1-2 21 Table 3.3.2.4.1-3. Summary of Technical Safety Requirements for 22
Flammable Gas Accidents. ............................................................. T3.3.2.4.1-5 23 Table 3.3.2.4.3-1. Summary of Frequency and Consequences for Waste Leak 24
and Misroute Accidents Without Controls ..................................... T3.3.2.4.3-1 25 Table 3.3.2.4.3-2. Safety-Significant Structures, Systems, and Components for 26
Waste Leak and Misroute Accidents. ............................................. T3.3.2.4.3-2 27 Table 3.3.2.4.3-3. Summary of Technical Safety Requirements for Waste Leak 28
and Misroute Accidents. ................................................................. T3.3.2.4.3-4 29 Table 3.3.2.4.3-4. Summary of Frequency and Consequences for Waste Leak 30
and Misroute Accidents With Controls. ....................................... T3.3.2.4.3-5 31 Table 3.3.2.4.5-1. Safety-Significant Structures, Systems, and Compoenents 32
for Natural Events. ......................................................................... T3.3.2.4.5-1 33 Table 3.3.2.4.5-2. Summary of Technical Safety Requirements for 34
Natural Events ................................................................................ T3.3.2.4.5-2 35 Table 3.4.1-1. Site Boundary Distances ...................................................................... T3.4.1-1 36 Table 3.4.1-2. Isotopes Listed in Best-Basis Inventory Database ............................... T3.4.1-2 37 Table 3.4.1-3. Dispersion Coefficients for 200 Area Facilities to 38
Onsite Receptor at 100 m ..................................................................... T3.4.1-3 39 Table 3.4.1-4. Dispersion Coefficients for 200 Area Facilities to 40
Hanford Site Boundary Receptor ......................................................... T3.4.1-3 41 Table 3.4.2.3-1. Offsite Radiological Consequences for Bounding Accidents 42
Postulated to Result from a Design Basis Earthquake ...................... T3.4.2.3-1 43 44
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LIST OF TERMS 1 2 3 A anticipated 4 AC administrative control 5 AEGL Acute Exposure Guideline Level 6 AMAD activity median aerodynamic diameter 7 AMU aqueous makeup (room) 8 ARF airborne release fraction 9 ARM area radiation monitor 10 ARR airborne release rate (for continuous releases) 11 BBI Best-Basis Inventory 12 BEU beyond extremely unlikely 13 CFR Code of Federal Regulations 14 DBA design basis accident 15 DCF dose conversion factors 16 DOE U.S. Department of Energy 17 DR damage ratio 18 DSA documented safety analysis 19 DST double-shell tank 20 Ecology Department of Ecology 21 ERPG emergency response planning guideline 22 EU extremely unlikely 23 F fast absorption type 24 HEPA high-efficiency particulate air (filter) 25 HIHTL hose-in-hose transfer line 26 HPT health physicist technician 27 HVAC heating, ventilation, and air conditioning 28 IBC International Building Code 29 IQRPE independent qualified registered professional engineer 30 KE Key Element 31 LCO limiting condition for operation 32 LFL lower flammability limit 33 LPF leak path factor 34 M medium absorption type 35 MAR material at risk 36 MCS monitoring and control system 37 MOI maximally-exposed offsite individual 38 NFPA National Fire Protection Association 39 NRC U.S. Nuclear Regulatory Commission 40 ORP Office of River Protection 41 OSHA Occupational Safety and Health Administration 42 PAC Protective Action Criteria 43 PC performance criteria 44 RF respirable fraction 45 S slow absorption type 46 SAC Specific Administrative Control 47
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SDC Seismic Design Categtory 1 SIL safety integrity level 2 SIS safety instrumented system 3 SMP safety management program 4 SOF sum of fractions 5 SS safety significant 6 SSC structures, systems, and components 7 SST single-shell tank 8 SWIM stop work, warn others, isolate the area, and minimize exposure 9 TED total effective dose 10 TEEL Temporary Emergency Exposure Limit 11 TNT trinitrotoluene 12 TOC Tank Operations Contractor 13 TSR technical safety requirement 14 TWA time-weighted average 15 U unlikely 16 ULD unit-liter dose 17 USOF unit sum-of-fraction 18 WAC Washington State Administrative Code 19 χ/Q atmospheric dispersion coefficient 20
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3.0 HAZARD AND ACCIDENT ANALYSES 1 2
3
3.1 INTRODUCTION 4 5
This chapter describes the methodology and presents the results of the hazard and accident 6
analyses performed for the 242-A Evaporator described in Chapter 2.0. This chapter also 7
includes the 242-A Evaporator hazard categorization. Based on the results of the hazard and 8
requirements (TSR), including Specific Administrative Controls (SAC) and Key Elements of 10
Administrative Controls; and additional defense-in-depth features are identified for protection of 11
the public, onsite workers, and facility workers. Chapter 4.0 provides details on the identified 12
safety SSCs and SACs, and Chapter 5.0 provides the details on the identified Administrative 13
Control (AC) Key Elements. Design and operational features required specifically to protect the 14
environment from uncontrolled releases of radioactive and hazardous material are also identified 15
in this chapter. 16
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3.2 REQUIREMENTS 1 2 Design codes, standards, regulations, and U.S. Department of Energy (DOE) Orders required for 3 establishing the 242-A Evaporator safety basis specific to this chapter and pertinent to the safety 4 analysis include the following: 5 6
• Title 10, Code of Federal Regulations, Part 830 (10 CFR 830), “Nuclear Safety 7 Management” 8
9 • DOE G 421.1-2, Implementation Guide for Use in Developing Documented Safety 10
Analyses to Meet Subpart B of 10 CFR 830 11 12
• DOE O 420.1C, Facility Safety 13 14
• DOE-STD-1020-2016, Natural Phenomena Hazards Analysis and Design Criteria for 15 DOE Facilities 16
Guidelines for Structures, Systems, and Components 19 20
• DOE-STD-1027-92, Hazard Categorization and Accident Analysis Techniques for 21 Compliance with DOE Order 5480.23, Nuclear Safety Analysis Reports 22
23 • DOE-STD-1186-2004, Specific Administrative Controls 24
25 • DOE-STD-1189-2008, Integration of Safety into the Design Process 26
27 • DOE-STD-3009-94, Preparation Guide for U.S. Department of Energy Nonreactor 28
Nuclear Facility Documented Safety Analyses 29 30
• DOE-STD-3014-96, Accident Analysis for Aircraft Crash into Hazardous Facilities 31 32 DOE has provided additional direction on the definition of the Hanford Site boundary and on 33 nuclear safety control selection and classification. This direction is provided in the following 34 letters: 35 36
• The definition of the Hanford Site boundary for safety analyses is contained in: 37 38
− Scott (1995), “Clarification of Hanford Site Boundaries for Current and Future Use in 39 Safety Analyses” 40
41 − Kruger (1996), “Further Discussion on Previous Site Boundary Memorandum” 42
43
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• Direction on nuclear safety control selection and classification is provided in: Hader 1 (2014) “Revision on Direction to Implement New Safety Classification Process for the 2 Tank Farms and 242-A Evaporator Documented Safety Analysis and new Capital 3 Projects.” 4
5 6 3.2.1 References 7 8 10 CFR 830, “Nuclear Safety Management,” Office of the Federal Register (FR 1810, Vol. 66, 9
No. 7), January 10, 2001. 10 11 DOE G 421.1-2, 2001, Implementation Guide for Use in Developing Documented Safety 12
Analyses to Meet Subpart B of 10 CFR 830, U.S. Department of Energy, Washington, 13 D.C. 14
15 DOE O 420.1C, Chg 1, 2015, Facility Safety, U.S. Department of Energy, Washington, D.C. 16 17 DOE-STD-1020-2016, 2016, Natural Phenomena Hazards Analysis and Design Criteria for 18
DOE Facilities, U.S. Department of Energy, Washington, D.C. 19 20 DOE-STD-1021-93, 2002, Natural Phenomena Hazards Performance Categorization Guidelines 21
for Structures, Systems, and Components, U.S. Department of Energy, Washington, D.C. 22 23 DOE-STD-1027-92, 1997, Hazard Categorization and Accident Analysis Techniques for 24
Compliance with DOE Order 5480.23, Nuclear Safety Analysis Reports, Change Notice 25 No. 1, U.S. Department of Energy, Washington, D.C. 26
27 DOE-STD-1186-2004, 2004, Specific Administrative Controls, U.S. Department of Energy, 28
Washington, D.C. 29 30 DOE-STD-1189-2008, 2008, Integration of Safety into the Design Process, U.S. Department of 31
Energy, Washington, D.C. 32 33 DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor 34
Nuclear Facility Documented Safety Analyses, Change Notice No. 3, U.S. Department of 35 Energy, Washington, D.C. 36
37 DOE-STD-3014-96, 1996, Accident Analysis for Aircraft Crash into Hazardous Facilities, 38
U.S. Department of Energy, Washington, D.C. 39 40 Hader, W. E., 2014, “Revision on Direction to Implement New Safety Classification Process for 41
the Tank Farms and 242-Evaporator Documented Safety Analysis and New Capital 42 Projects,” (letter 14-NSD-015/1401829 to L. D. Olsen, Washington River Protection 43 Solutions LLC, May 14), U.S. Department of Energy, Office of River Protection, 44 Richland, Washington. 45
46
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Kruger, P. W., 1996, “Further Discussion on Previous Site Boundary Memorandum,” 1 (letter 9600588 to Director, Pacific Northwest National Laboratory, and President, 2 Westinghouse Hanford Company, March 5), U.S. Department of Energy, Richland 3 Operations Office, Richland, Washington. 4
5 Scott, W. B., 1995, “Clarification of Hanford Site Boundaries for Current and Future Use in 6
Safety Analyses,” (letter 9504327 to Director, Pacific Northwest Laboratory, and 7 President, Westinghouse Hanford Company, September 26), U.S. Department of Energy, 8 Richland Operations Office, Richland, Washington. 9
10
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3.3 HAZARD ANALYSIS 1 2
The methodology and results of the hazard analysis conducted for the 242-A Evaporator 3
described in Chapter 2.0 are presented in this section. The results of the final hazard 4
categorization of the 242-A Evaporator are also presented. 5
6
The types of events considered in the 242-A Evaporator hazard analysis were internal events, 7
external events, and natural events that cause the uncontrolled release of radioactive and other 8
hazardous material and affect the public, workers, or the environment. Single and multiple 9
failures (i.e., as a result of equipment and human errors) and common cause failures were 10
considered to be accident initiators. Sabotage and terrorism events were not considered. 11
12
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3.3.1 Methodology 1 2
This section identifies the methodology used to perform the hazard analysis for the 242-A 3
Evaporator. The methodology was designed to meet the guidance in DOE-STD-3009-94, 4
Preparation Guide for U.S. Department of Energy Nonreactor Nuclear Facility Documented 5
Safety Analyses. In addition, the methodology follows the guidance for hazard analysis and 6
guidelines for nuclear safety control selection and classification provided by U.S. Department of 7
Energy (DOE) in Hader (2014). 8
9
The hazard analysis process consists of the following major elements: 10
11
• Hazard Identification 12
• Hazard Evaluation 13
• Accident Selection 14
• Controls Identification 15
• Hazard Categorization 16
• Hazard Evaluation Database 17
18
Information/understanding generated during a process step can result in the need to update 19
previous steps. The hazard analysis results are final only when no further iteration is needed. 20
Results of the hazard and accident analysis activities are systematically organized and recorded 21
in RPP-48900, 242-A Evaporator Hazard Evaluation Database Report, and are discussed in 22
Section 3.3.2. 23
24
The following sections provide brief descriptions of the hazard analysis elements. 25
26
3.3.1.1 Hazard Identification. The initial step in the hazard analysis process is to identify 27
the potential hazards present at the 242-A Evaporator. Hazards are defined as material at risk 28
(MAR) present at the 242-A Evaporator that could have a potential adverse effect on people or 29
the environment, and energy sources that are present that could potentially contribute to the 30
release of the MAR or directly harm a worker. A hazard identification checklist is used in the 31
hazard identification process for the 242-A Evaporator. A sample copy of this form is provided 32
in Table 3.3.1.1-1. Specific MAR assumptions are developed from information (e.g., design 33
media that provide tank/vessel volumes, sample analysis, historical records on past campaigns) 34
describing the configuration and process history of the 242-A Evaporator. Details on the 35
development of radiological and toxicological source terms for hazard and accident analyses are 36
presented in Section 3.4.1. 37
38
The hazard identification process for the initial DOE-STD-3009-94 compliant safety basis also 39
included a review of the historical occurrence reports for the 242-A Evaporator. These 40
occurrence reports were compared against the identified hazardous conditions with additional 41
hazardous conditions being developed to ensure that a comprehensive set of hazards and 42
potential release mechanisms were identified. This review of the historical occurrence reports 43
also assisted in assigning frequency ranges for the associated hazardous conditions. 44
45
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The initial hazards identification was completed through a review of the 242-A Evaporator 1
designs, processes, operations, and operational experience at the facility level during 2
development of the first DOE-STD-3009-94 compliant safety basis document for 242-A 3
Evaporator. Although creation of the initial hazards inventory was an important achievement, 4
hazard identification is an ongoing process that progresses in lockstep with the facility and 5
mission. As part of the change control process, physical modifications to the facility, new or 6
modified activities, and new technical information are evaluated to identify new hazards and to 7
delete or modify those hazards eliminated through design change, refined analyses which show 8
that physical conditions do not support the hazard phenomenology, or completion of remediation 9
activities. In addition, occurrence reports with safety basis implications are evaluated on a real-10
time basis and provide an important input into the hazards identification process, particularly 11
those identifying potential inadequacies in the safety analyses which may drive the creation of 12
new hazardous conditions or the modification of existing hazardous conditions. 13
14
Occupational hazards are also identified as part of the hazard identification process, but are not 15
further evaluated. These hazards are specifically addressed by the controls developed and 16
implemented by the contractually mandated safety management programs. Occupational hazards 17
include: 18
19
• Standard industrial hazards, for example, falling objects; high and low temperatures; 20
explosions of compressed gas cylinders, including flammable gas cylinders; oxygen 21
deficiency (i.e., asphyxiation); exposure to toxic materials (e.g., asbestos); falls from 22
heights; rotating equipment; electrical hazards; fires; high pressure; lifting, bending, and 23
• DOE G 421.1-2, Implementation Guide for Use in Developing Documented Safety 25
Analyses to Meet Subpart B of 10 CFR 830 26
27
• DOE G 423.1-1, Implementation Guide for Use in Developing Technical Safety 28
Requirements 29
30
• DOE-STD-3009-94 31
32
• DOE-STD-1186-2004, Specific Administrative Controls 33
34
• DOE-STD- 1189-2008, Integration of Safety into the Design Process 35
36
• Hader (2014) 37
38
• Charboneau (2012), “Designation of New Installed Equipment Used to Support 39
Technical Safety Requirements (TSR) as Safety-Significant (SS)” 40
41
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The overall hierarchy of control decision preference is defined in DOE-STD-1189-2008 as 1
follows: 2
3
• Minimization of hazardous materials is the first priority 4
5
• Safety SSCs are preferred over ACs 6
7
• Passive SSCs are preferred over active SSCs 8
9
• Preventive controls are preferred over mitigative controls 10
11
• Facility safety SSCs are preferred over personal protective equipment 12
13
• Controls closest to the hazard may provide protection to the largest population of 14
potential receptors, including workers and the public 15
16
• Controls that are effective for multiple hazards can be resource effective 17
18
The cost of implementation and maintenance of available controls is also considered as part of 19
control selection. 20
21
Control selection and classification for radiological protection of the offsite public. 22 Safety-class SSCs and TSRs are selected and classified based on the quantitative radiological 23
consequence analysis of the bounding (design basis) accidents in Section 3.4.2. If the offsite 24
radiological consequences are ≥ the 25 rem total effective dose (TED) Evaluation Guideline 25
from DOE-STD-3009-94, Appendix A, then safety-class SSCs or TSRs are required for 26
protection of the offsite public. An accident is considered to challenge the Evaluation Guideline 27
if the offsite dose is ≥ 5 rem TED, but < 25 rem TED. When the consequences are in this range, 28
safety-class designation must be considered, and the rationale for the decision to classify or not 29
classify an SSC as safety class should be explained and justified. In addition, accidents with 30
offsite radiological consequences that are ≥ 1 rem but < 5 rem with a frequency > 1E-04/yr must 31
also be considered for safety-significant SSCs or TSRs. 32
33
Control selection and classification for protection of the onsite worker and offsite public 34 (toxicological exposure only). Safety-significant SSCs and TSRs are selected based on the 35
results of the qualitative hazard evaluation of representative accidents in Section 3.3.2.4. Offsite 36
toxicological and onsite radiological and toxicological consequences are used for identifying 37
safety-significant SSCs and TSRs. Accidents with consequences that are ≥ 100 rem or 38
> protective action criteria (PAC)-3 to the onsite worker, or > PAC-2 to the offsite public, 39
require safety-significant SSCs or TSRs. 40
41
Control selection and classification for protection of the facility worker. Safety-significant 42
SSCs and TSRs are also considered for significant facility worker hazards (i.e., a prompt worker 43
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fatality, serious injuries to workers, significant radiological or chemical exposures to workers). 1
Conditions that present a significant consequence to the facility worker include: 2
3
• Energetic releases of high concentrations of radiological or toxic chemical materials 4
where the facility worker would normally be immediately present and therefore unable to 5
take self-protective actions. 6
7
• Deflagrations or explosions within process equipment or confinement/containment 8
structures or vessels where grievous injury or death to a facility worker may result from 9
the fragmentation of the process equipment failing or the confinement (or containment) 10
with the facility worker close by. 11
12
• Chemical or thermal burns to a facility worker that could reasonably cover a significant 13
portion of the facility worker’s body, where self-protective actions are not reasonably 14
available due to the speed of the event or where there may be no reasonable warning to 15
the facility worker of the hazardous condition. (Note: This guidance is limited to those 16
areas that are “normally occupied spaces” [i.e., does not apply to transient occupied 17
areas, such as corridors].) 18
19
• Exposures to radiological or toxic materials of sufficient magnitude that death or ongoing 20
large-scale medical intervention may reasonably be expected to result. These exposures 21
are defined as > 100 rem TED or > PAC-3 to the facility worker. 22
23
• Leaks from process systems where asphyxiation of a facility worker normally present 24
may result. 25
26
• Other conditions, with a significant facility worker consequence, which are unique to a 27
specific process. 28
29
Classification of Administrative Controls as Specific Administrative Controls. ACs may be 30
implemented as SACs or as Key Elements. An AC is implemented as an SAC when: 31
32
• It is credited in the hazard or accident analysis to prevent or mitigate an event with 33
consequences that are ≥ 5 rem TED or > PAC-2 to the offsite public* 34
35
• It is credited in the hazard or accident analysis to prevent or mitigate an event with 36
consequences that are ≥ 100 rem TED or > PAC-3 to the onsite worker* 37
38
• It is credited in the hazard analysis to protect the facility worker from a significant 39
facility worker hazard* 40
41
• It protects an important initial condition assumed in the hazard analysis (e.g., an 42
assumption on MAR inventory limits) 43
44
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* Another requirement for SAC designation is that the AC was selected when an SSC was 1
available or could have been designed and installed to perform the credited safety function 2
(without consideration of cost or schedule). 3
4
ACs selected as important contributors to defense-in-depth and ACs that provide a support 5
function to SACs or LCOs are implemented as Key Elements. (Note: ACs selected as important 6
contributors to defense-in-depth are not credited with preventing or mitigating a 7
hazard/accident.) 8
9
Classification of Equipment (Including Instrumentation) Used to Support TSRs. 10 Equipment (including instrumentation) used to support TSRs are classified as follows. 11
12
• Permanently installed equipment (including instrumentation) where the equipment or 13
instrument reading provides a safety function to prevent or mitigate an accident as 14
directed in the TSRs (i.e., used to determine the entry condition into a Limiting Condition 15
for Operation [LCO] action statement or relied upon to initiate an action in a SAC) shall 16
be classified as safety significant. 17
18
• Permanently installed equipment (including instrumentation) where the equipment or 19
instrument reading is only used to perform an analysis is not to be classified as safety 20
significant. 21
22
• Portable equipment controlled as Measuring and Test Equipment does not need to be 23
classified as safety significant. 24
25
Classification of SSCs that Monitor Initial Conditions Assumed in the Accident Analysis. 26 SSCs that function to monitor initial conditions assumed in the accident analysis are not required 27
to be classified as safety SSCs based on the monitoring function if all the following conditions 28
are met. 29
30
• They do not generate a signal (indication, alarm, or interlock function) that causes action 31
(operator action or equipment change of state) that is required to prevent or mitigate an 32
accident. 33
34
• Their failure is not the initiator of an accident. 35
36
• Violation of the monitored parameter is not the initiator of an accident. 37
38
Identification of Safety Instrumented Systems and Determination of the Safety Integrity 39 Level. Controls involving safety-significant instruments (including sensors, logic solvers, and 40
final control elements) are safety instrumented systems (SIS) and include operator actions 41
directed by LCO action statements or actions in a SAC. ANSI/ISA-84.00.01-2004, Functional 42
Safety: Safety Instrumented Systems for the Process Industry Sector, is used in the design of SIS 43
and requires the determination of a safety integrity level (SIL). Because the SIL determination 44
for a SIS is dependent on and may affect the selection of other controls for the hazard/accident, 45
SIL determination is performed during control selection. 46
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1
A SIL is assigned based on an evaluation using the criteria shown in Table 3.3.1.5-1. The 2
Table 3.3.1.5-1 criteria consider the accident frequency; the accident consequences; applicable 3
independent protection layers; and, for significant facility worker hazards, other measures that 4
provide protection to the facility worker. Protection layers include safety-class or 5
safety-significant SSCs, SACs, and AC Key Elements. Independent layers are those that are 6
independent of the initiating event and the components of other protection layers for the same 7
accident scenario. Other measures that provide protection to the facility worker include items 8
required by safety management programs, items required by contractually mandated codes and 9
standards, and defense-in-depth features described in the DSA. If the SIS addresses more than 10
one accident scenario, the assigned SIL is the highest required for the applicable accident 11
scenarios. 12
13
Defense-in-Depth Features. In addition to the safety SSCs and TSRs selected to prevent or 14
mitigate potential hazardous conditions and postulated accidents at the 242-A Evaporator, other 15
non-safety SSCs and non-TSR administrative features may be identified for defense-in-depth 16
(see Section 3.3.2.3.2). In general, more layers of defense-in-depth (i.e., non-safety SSCs, 17
non-TSR administrative features) are selected for higher consequence accidents. There is no 18
requirement to demonstrate any generic, minimum number of layers of defense. 19
20
Safety SSC and TSR control decisions, and the identification of other SSCs and administrative 21
features for defense-in-depth, are made at scheduled meetings of cognizant and affected 242-A 22
Offsite public Onsite co-located worker Site facility worker
≥ 25 rem TED
Safety-Class SSCs or TSRs (SACs) are
required
≥ 100 rem TED or > PAC-3
Safety-Significant SSCs or TSRs
(SACs) are required
All facility worker hazards
are assessed for prompt
death or serious injury or
significant radiological or
chemical exposure
≥ 5 rem TED to < 25 rem TED
Safety-Class (may be justified as
Safety-Significant) SSCs or TSRs
(SACs) are considered
≥ 1 rem TED to < 5 rem TED
and
Frequency > 1E-04/yr
Safety-Significant SSCs or TSRs (Key
Elements of ACs) are considered
≥ 0.1 rem TED to < 5 rem TED
To assist in the determination of
sufficient defense-in-depth, this range
provides a perspective for consideration
to be discussed between the TOC and
ORP
≥ 5 rem TED to < 100 rem TED
To assist in the determination of
sufficient defense-in-depth, this range
provides a perspective for consideration
to be discussed between the TOC and
ORP
> PAC-2
Safety-Significant SSCs or TSRs
(SACs) are required
Notes:
AC = Administrative Control.
ORP = Office of River Protection.
PAC = Protective Action Criteria.
SAC = specific administrative control.
SSC = structures, systems, and components.
TED = total effective dose.
TOC = Tank Operations Contractor.
TSR = technical safety requirement.
1
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Table 3.3.1.5-1. Safety Integrity Level Determination for Safety Instrumented Systems.
Consequence Frequency
Anticipated Unlikely Extremely Unlikely
Offsite public SIL-2a SIL-2a SIL-1
Onsite co-located worker SIL-2a SIL-1 SIL-1
Site facility worker SIL-1b SIL-1 SIL-1
Notes:
a May be reduced to SIL-1 if an independent protection layer (i.e., safety-class or safety-significant SSC,
SAC, or AC Key Element) is also selected. b Shall be increased to SIL-2 if there are no other additional measures to protect the facility worker.
AC = administrative control.
SAC = Specific Administrative Control.
SIL = safety integrity level.
SSC = structures, systems, and components.
1
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3.3.2 Hazard Analysis Results 1 2 This section presents the results of the hazard analysis activities. The hazard analysis is focused 3 on uncontrolled releases of radioactive and other hazardous material and worker safety. 4 Radiation protection and occupational safety hazardous conditions discovered by the analysis are 5 documented and addressed in the appropriate safety management program (SMP). The results of 6 the hazard analysis activities include: 7 8
13 Data from the hazard identification and evaluation activities are captured in hazard evaluation 14 reports and the results from these reports are synthesized into RPP-48900, 242-A Evaporator 15 Hazard Evaluation Database Report. The methodology used to perform the hazards analysis 16 activities is summarized in Section 3.3.1. 17 18 3.3.2.1 Hazard Identification and Hazardous Condition Development. The initial steps in 19 the hazard analysis process are to identify the hazards and then develop and evaluate the 20 potential hazardous conditions that could result. This section discusses the results of these 21 activities. 22 23 3.3.2.1.1 Hazard Identification. The results of the hazard identification process identified the 24 following: 25 26
• Material at risk (MAR) in the 242-A Evaporator; 27 28
• Energy sources, with a focus on those that could potentially contribute to the uncontrolled 29 release of MAR, including natural events and external events; 30
31 • Summary of occurrences; and 32
33 • Hazards identified but not included in the hazard evaluation. 34
35 The hazard identification results are discussed in the following sections. 36 37 3.3.2.1.1.1 Material at Risk. The MAR is the material at a facility with the potential to have an 38 adverse effect on people or the environment. In the 242-A Evaporator, the MAR is the 39 radioactive and toxicologically hazardous waste including waste feed transferred from the tank 40 farms to the C-A-1 vessel, waste in the C-A-1 vessel (including the E-A-1 reboiler and 41 recirculation line), and waste slurry transferred back to the tank farms. In addition, toxic process 42 offgas (primarily ammonia) is a non-radioactive MAR. 43 44 The C-A-1 vessel nominally contains 26,000 gal of waste during evaporator operations. Waste is 45 fed to the C-A-1 vessel at a rate of 70 to 130 gal/min. Waste slurry is returned to the tank farms 46
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at a rate of 30 to 70 gal/min. Only very small quantities of waste are present in the 242-A 1 Evaporator when it is shutdown between campaigns. 2 3 The attributes of the waste MAR of most importance to the safety basis are (1) the radiological 4 and chemical concentrations within the waste that are used to develop radiological and 5 toxicological source terms for accident consequences if there is a waste release and to determine 6 direct radiation hazards due to the penetrating radiation from the radionuclides 90Sr and 137Cs 7 with minor contributions from 3H, 14C, 79Se, 99Tc and other fission products; (2) the waste 8 composition from a flammable gas generation rate perspective (see Section 3.3.2.1.1.2); and (3) 9 the pH (i.e., ≥ 12.5) as a chemical (caustic) burn hazard. 10 11 Process offgas (primarily ammonia) can be released from the vessel ventilation system. 12 Ammonia is very soluble in the liquid phase of tank waste. Therefore, a certain amount of 13 ammonia is found in waste feed to the 242-A Evaporator. As waste feed is heated to evaporation 14 in the C-A-1 vessel, ammonia is released as ammonia gas, along with water vapor. Ammonia 15 gas passes from the C-A-1 vessel to the condensers, where a large portion of it condenses with 16 the water vapor into process condensate. The remaining non-condensed portion is discharged 17 through the vessel ventilation system as a gas to the environment. The attribute of the process 18 offgas MAR of most importance to the safety basis is the ammonia gas concentration. 19 20 Process condensate is normally only slightly radioactive, is chemically dilute, has a pH of less 21 than 12.5, and, therefore, is not considered to be MAR. Steam condensate and raw water are not 22 normally contaminated. However, process condensate, steam condensate, and raw water 23 (interfacing systems) can be contaminated by waste due to misroutes. Contaminated process 24 condensate, steam condensate, and raw water are MAR considered in the hazard analysis. 25 26 Non-radioactive chemicals (e.g., chemicals used during condensate sampling) are controlled by 27 industrial safety standards (i.e., Occupational Safety and Health Administration and U.S. 28 Department of Transportation) and are not analyzed in the documented safety analysis (DSA) 29 according to DOE-STD-3009-94, Preparation Guide for U.S. Department of Energy Nonreactor 30 Nuclear Facility Safety Analyses. 31 32 3.3.2.1.1.2 Energy Sources. The next step in the hazard identification process is to identify the 33 energy sources that could interact with and contribute to the uncontrolled release of the MAR. 34 The energy sources are identified during hazard evaluations of the 242-A Evaporator using the 35 energy source checklist shown in Table 3.3.1.1-1. A summary of energy sources that have the 36 potential to interact with MAR is provided below. Complete descriptions of the individual 37 hazardous conditions, MAR, and event initiators are documented in RPP-48900. 38 39 Pumps. Pumped (pressurized) waste exists in the feed line during waste transfers to the C-A-1 40 vessel from the tank farms using feed pump 241-AW-P-102-1 and in the slurry line during waste 41 transfers to the tank farms from the C-A-1 vessel using slurry pump P-B-2. Condensates 42 contaminated due to a misroute can be pumped by process condensate pump P-C-100, process 43 condensate recycle pump P-C-106, and steam condensate sample pump P-RC-1. The pump 44 provides the motive force driving the leak. 45 46
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Gravity head. Waste (MAR), under hydrostatic head only, exists in the C-A-1 vessel (includes 1 the E-A-1 reboiler and recirculation line). Gravity head provides the motive force driving the 2 leak). 3 4 Steam. Steam is used to provide heat to the evaporation process in the E-A-1 reboiler. A failure 5 in the E-A-1 reboiler (tubes/tube sheet and shell) could allow escaping steam to entrain waste 6 and release it into the evaporator room. Steam is also used to transfer (jet) the pump room sump 7 to tank farms. The steam interacts with the waste during waste transfers using the pump room 8 sump steam jet pump J-B-1. Steam jet pump J-B-1 lifts the waste from the sump into drain line 9 DR-334 by steam eductor vacuum. The waste then gravity drains to double-shell tank (DST) 10 241-AW-102. The steam could also interact with waste if the steam/waste discharge for the 11 pump room sump steam jet pump J-B-1 is blocked and the steam supply flows down the inlet 12 side of the sump jet eductor and is injected into a waste pool in the sump, causing the generation 13 of waste aerosols due to entrainment or bubble burst. 14 15 Ventilation air flow. Waste contamination (MAR) collects in the vessel ventilation system and 16 the K1 ventilation system (e.g., duct work, high efficiency particulate air [HEPA] filters) and can 17 be released due to ventilation system upsets (high pressure/differential pressure, high 18 temperature, impacts). Process offgas (primarily ammonia) (MAR) is released from the vessel 19 ventilation system. 20 21 Flammable gas. One potential energy source associated with the waste is flammable gas. This 22 energy source is related to the MAR discussion in the previous section because waste generates 23 flammable gas, primarily hydrogen, and the steady-state generation rates are based, in part, on 24 waste composition. In addition to the waste in the feed line, the C-A-1 vessel, and the slurry 25 line, where waste is expected to be located, waste that is misrouted into interfacing systems 26 (process condensate, steam condensate, raw water systems) can also pose a flammable gas 27 hazard. 28 29 Flammables/combustibles. The majority of flammable liquids present in or near the 242-A 30 Evaporator are fuels used by the package boiler, the backup diesel generator, and vehicles such 31 as cars and trucks that support the 242-A Evaporator. These flammables cannot interact with the 32 MAR in the 242-A Evaporator. 33 34 There can be transient combustibles in the 242-A Evaporator. HNF-SD-WM-FHA-024, Fire 35 Hazards Analysis for the Evaporator Facility (242-A), assumes 250 kg of transient combustible 36 materials in the evaporator room, and small quantities of flammable liquids stored in an 37 approved flammable liquid storage cabinet in the aqueous makeup (AMU) room and the 38 condenser room. In addition, the HEPA filters in the vessel ventilation system and the K1 39 ventilation system are combustible. 40 41 (Note: The transient combustibles are controlled in the evaporator room and pump room during 42 operation. See Section 4.5.3. “Evaporator and Pump Room Transient Combustible Material 43 Controls.”) 44 45 Additional information on flammables and combustibles can be found in HNF-SD-WM-FHA-024. 46 47
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External Events. Energy sources from external events are addressed in Section 3.3.2.4.4. 1 2 Natural Events. Energy sources from natural events are addressed in Section 3.3.2.4.5. 3 4 3.3.2.1.1.3 Summary of 242-A Evaporator Occurrences. Hazard identification activities 5 included a review of the historical 242-A Evaporator occurrence reports and a search of the 6 complex wide occurrence report database using key word “evaporator” and the following 7 reporting criteria. 8 9
GROUP 1 − Operational Emergencies 10 • All 11
GROUP 2 − Personnel Safety and Health 12 • Subgroup B - Occupational Exposure 13 • Subgroup D - Explosions 14
GROUP 3 − Nuclear Safety Basis 15 • Subgroup B - Documented Safety Analysis Inadequacies 16 • Subgroup C - Nuclear Criticality Safety Control Violations 17
GROUP 4 − Facility Status 18 • Subgroup B – Operations 19 • Subgroup C - Radiation Exposure 20
GROUP 5 − Environmental 21 • Subgroup A - Releases 22
GROUP 6 − Contamination/Radiation Control 23 • All 24
These reports were examined to identify potential hazards and initiators to ensure that a 25 comprehensive set of hazards and potential release mechanisms were identified. 26 27 Types of events which are documented in the occurrence reports and are relevant to hazard 28 identification include the following. 29 30
• Contaminated steam condensate due to heat exchanger tube/tube sheet leak 31 • Process condensate transfer leak 32 • Waste transfer system overpressure due to pump over speed 33 • Waste transfer system leaks 34 • Waste transfer system valves mispositioned 35 • Waste transfer system water hammer 36 • Waste misroute due to operator error 37 • Steam system pressure transients 38 • Contaminated water system due to a leak and loss of cooling water pressure 39
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• High radiation area left unsecured 1 • Loss of power 2 • Loss of ventilation 3
4 Although the historical review was conducted in 2012, occurrence reports continue to be an 5 important input into the hazard identification process. Per the occurrence reporting process, 6 occurrences are evaluated for safety basis implications. Those that indicate potential 7 inadequacies in the safety analysis are evaluated through the unreviewed safety question process 8 and, if the inadequacy is confirmed, the safety basis is revised, as necessary. Identification of 9 new hazardous conditions and modification of existing hazardous conditions is a frequent 10 outcome after an inadequacy in the safety analysis has been confirmed. 11 12 3.3.2.1.1.4 Hazards Identified But Not Included in the Analysis Results. This section 13 contains a discussion of phenomena that were formerly identified as potential hazards in the 14 242-A Evaporator but after subsequent evaluation were found to be not plausible. 15 16 Organic Solvent Fires. An organic solvent fire in the 242-A Evaporator is not plausible based 17 on the following evaluation. The organic solvent hazard in tank farms is evaluated in 18 RPP-13384, Organic Solvent Technical Basis Document, and HNF-4240, Organic Solvent 19 Topical Report. The analysis for tank farms (i.e., DSTs) bounds the hazard in the 242-A 20 Evaporator (i.e., C-A-1 vessel or TK-C-100) where a separable organic layer could potentially be 21 present. The layer would first need to be present in the DSTs to be fed to the 242-A Evaporator 22 and such a layer is unlikely to exist in the DSTs at this time due to aging. If present, any 23 separable organic left in the DSTs would be less combustible than that evaluated. 24 25 It is highly unlikely that a combustible organic layer could be present in the 242-A Evaporator. 26 Potential organic liquids (solvents) in tank farms are evaluated in HNF-4240. The presence of a 27 separable organic layer in a DST (feed source for the 242-A Evaporator) is unlikely given the 28 DST conditions (strongly alkaline wastes, strong radiation fields, actively ventilated) that results 29 in organic degradation/aging by evaporation, hydrolysis, and radiolysis. Any remaining 30 separable organics would be low volatility and low reactivity. It is important to note that a 31 separable organic layer could also be introduced as lubricating oil from the air lift circulator 32 compressors. Note that these lubricating oils are less volatile and have higher flash points than 33 the organic compounds analyzed in HNF-4240. 34 35 Vapors would not be in flammable concentrations. Even the relatively volatile floating organic 36 layer that used to be stored in 241-C-103 had a flash point of 244°F and to create flammable 37 vapors in the tank headspace at 25% of the lower flammability limit (LFL), would need to be 38 heated to ≥ 257°F. The organic layer would need to be heated to ≥ 322°F for the vapors in the 39 tank headspace to reach 100% of the LFL (HNF-4240, Section 3.1.2). 40 41 Pool fire ignition is not credible. Even the relatively volatile floating organic layer that used to 42 be in 241-C-103 would be extremely difficult to ignite when the bulk liquid is below its 43 flashpoint. The organic liquid needs to be heated to its flash point (locally) to create a flammable 44 vapor boundary layer and an ignition source would need to be present in the flammable vapor 45 boundary layer. The only potential ignition source identified for a DST is a vehicle fuel spill/fire 46 (HNF-4240, Section 4.1 and Table 7-2). This is not applicable to the 242-A Evaporator. 47
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Ignition of a pool fire (even if there were a separable organic layer in the vessel) is not credible 1 due to a lack of credible ignition sources. 2 3 Hazard Evaluation Database. Hazard evaluation reports are developed to document the hazards 4 associated with the 242-A Evaporator (and changes thereto). The results of these hazard 5 evaluations are consolidated into RPP-48900, which documents the comprehensive hazard 6 evaluations in the 242-A Evaporator DSA. The hazard evaluation reports that provide input to 7 RPP-48900 and whose hazardous conditions have been mapped to RPP-48900 (see 8 Section 3.3.1) are listed therein. Additional information on the individual fields maintained in 9 RPP-48900 is provided within that document. 10 11 3.3.2.1.2 References. 12 13 DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor 14
Nuclear Facility Documented Safety Analyses, Change Notice No. 3, U.S. Department of 15 Energy, Washington, D.C. 16
Richland, Washington. 19 20 HNF-SD-WM-FHA-024, 2017, Fire Hazards Analysis for the Evaporator Facility (242-A), 21
Rev. 8C, Washington River Protection Solutions LLC, Richland, Washington. 22 23 RPP-13384, 2005,Organic Solvent Technical Basis Document, Rev. 2, CH2M HILL Hanford 24
Group, Inc., Richland, Washington. 25 26 RPP-48900, 242-A Evaporator Hazard Evaluation Database Report, as amended, Washington 27
River Protection Solutions LLC, Richland, Washington. 28
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3.3.2.2 Facility Hazard Categorization. Facility hazard categorizations are performed to 1
provide input for implementing a graded approach to develop safety analysis reports in 2
accordance with Title 10, Code of Federal Regulations, Part 830 (10 CFR 830), “Nuclear Safety 3
Management,” which defines three hazard categories based on the consequences of unmitigated 4
releases of radioactive and/or hazardous material. 5
6
• Hazard Category 1. The hazard analysis shows the potential for significant offsite 7
consequences. 8
9
• Hazard Category 2. The hazard analysis shows the potential for significant onsite 10
consequences. 11
12
• Hazard Category 3. The hazard analysis shows the potential for only significant 13
localized consequences. 14
15
DOE-STD-1027-92, Hazard Categorization and Accident Analysis Techniques for Compliance 16
with DOE Order 5480.23, Nuclear Safety Analysis Reports, provides a uniform methodology for 17
developing the initial and final facility hazard categorization under 10 CFR 830. This standard 18
also provides the threshold quantities for classifying the facility as Hazard Category 1, 2, or 3, 19
based on the quantity of radioactive material in the facility. All facilities classified as at least a 20
Hazard Category 3 in accordance with DOE-STD-1027-92 are required to comply with 21
10 CFR 830. Facilities that do not meet or exceed Hazard Category 3 threshold criteria but still 22
possess some amount of radioactive material may be considered “Radiological Facilities.” Per 23
10 CFR 830 Appendix A to Subpart B, “The safety basis requirements only apply to Hazard 24
Category 1, 2, and 3 nuclear facilities and do not apply to nuclear facilities below Hazard 25
Category 3.” 26
27
The final hazard categorization of a facility is based on the “unmitigated release” of hazardous 28
material from a credible accident scenario. For the purposes of hazard categorization, 29
DOE-STD-1027-92 states that “unmitigated” is meant to consider material quantity, form, 30
location, dispersibility, and interaction with available energy sources, but not to consider safety 31
features (e.g., ventilation system, fire suppression) which will prevent or mitigate a release. The 32
DOE-STD-1027-92 interpretation of significant onsite consequences is stated as facilities with 33
the potential for nuclear criticality events or facilities with sufficient quantities of hazardous 34
material and energy that on-site emergency planning activities are required. Based on the hazard 35
and accident analysis, unmitigated hazardous conditions present the potential for significant 36
onsite consequences (i.e., consequences exceed the site area emergency consequence threshold 37
of 1 rem at 100 m). As a result, final hazard categorization of Hazard Category 2 applies to the 38
242-A Evaporator. 39
40
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3.3.2.2.1 References 1 2
10 CFR 830, “Nuclear Safety Management,” Office of the Federal Register (FR 1810, Vol. 66, 3
No. 7), January 10, 2001. 4
5
DOE-STD-1027-92, 1997, Hazard Categorization and Accident Analysis Techniques for 6
Compliance with DOE Order 5480.23, Nuclear Safety Analysis Reports, Change Notice 7
No. 1, U.S. Department of Energy, Washington, D.C. 8
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3.3.2.3 Hazard Evaluation. The hazard evaluation for the documented safety analysis 1
(DSA) determined a set of potential hazardous conditions that could result in the uncontrolled 2
release of radioactive and/or hazardous material. The hazard evaluation process is summarized 3
in Section 3.3.1. 4
5
The hazard evaluation results are used to support the selection of accidents for more detailed 6
analysis during the accident analyses process and to support control decisions. The selection of 7
the controls for the safe operation of the tank farms is based on the results of accident and the 8
hazard analyses. 9
10
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3.3.2.3.1 Accident Selection. This section provides a summary of the representative accidents 1 and the basis for selecting the bounding accidents which are quantitatively analyzed for potential 2 offsite radiological consequences in Section 3.4.2. 3 4 Representative Accidents for Hazard Evaluation. Representative accidents have been 5 selected to represent groups of similar hazardous conditions and bound the onsite consequences 6 for the group of similar accidents. 7 8 The hazard evaluation results for the representative accidents that have consequences exceeding 9 the guidelines for the onsite worker are presented in Section 3.3.2.4. Also described in 10 Section 3.3.2.4 are external events and natural events; and hazardous conditions that pose 11 significant facility worker hazards. Other representative accidents (i.e., those with consequences 12 that are less than the guidelines for the onsite worker and do not pose significant facility worker 13 hazards) are briefly summarized in this section. Evaluations of the individual hazardous 14 conditions encompassed within the representative accidents are documented in RPP-48900, 15 242-A Evaporator Hazard Evaluation Database Report. Note that in the following descriptions 16 the term “bounding event” means the highest consequence event among the hazardous conditions 17 encompassed within the representative accident. 18 19
• Flammable Gas Accidents. This accident involves flammable gas 20 deflagrations/detonations in the C-A-1 vessel and also in waste feed transfer piping, 21 waste slurry transfer piping, and C-A-1 drain (dump) piping. In addition, flammable gas 22 deflagrations/detonations in the process condensate, steam condensate, and raw water 23 systems due to waste contamination as a result of misroutes are evaluated. As described 24 in Section 3.3.2.4.1, the bounding event is a flammable gas detonation in the C-A-1 25 vessel. See Section 3.3.2.4.1 for more detail on the evaluation of this accident, and 26 RPP-48900 for the evaluation of the associated hazardous conditions. 27
28 • Waste Leaks and Misroutes. This accident involves a broad spectrum of waste leaks 29
including (pumped) pressurized leaks, gravity head (C-A-1 vessel) leaks, and leaks 30 involving contaminated process condensate, steam condensate, and raw water due to 31 misroutes. Misroutes also consider direct radiation hazards to the facility worker. As 32 described in Section 3.3.2.4.3, the bounding event is a fine spray leak during a waste 33 transfer using slurry pump P-B-2. See Section 3.3.2.4.3 for more detail on the evaluation 34 of this accident, and RPP-48900 for the evaluation of the associated hazardous 35 conditions. 36
accident, range fire, or rail accident) of 242-A Evaporator accidents. See 39 Section 3.3.2.4.6 for more description of external events. Note that RPP-48900 has a 40 specific section for the hazardous condition related to aircraft crashes. Other external 41 event initiated hazardous conditions are located under the initiated representative accident 42 in RPP-48900. 43
44 • Natural Events. Natural events, which are not unique accidents (and hence not truly a 45
representative accident), encompass natural phenomena events (e.g., seismic events, 46 lightning, high winds) that serve as initiators of other representative accidents. For 47
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example, a seismic event could initiate a flammable gas accident or a waste leak. See 1 Section 3.3.2.4.5 for more description of natural events. Hazardous conditions initiated 2 by natural events are located under the initiated representative accident in RPP-48900. 3 For example, a seismically-induced leak is located with the waste leak and misroute 4 hazardous conditions. 5
6 The representative accidents listed below have consequences that are less than the guidelines for 7 the onsite worker and do not pose significant facility worker hazards. 8
9 • Ammonia releases. This accident involves off-normal releases of ammonia gas from the 10
vessel ventilation system due to high ammonia feed in C-A-1 vessel or 11 over-temperature events (e.g., fires) involving process condensate. The bounding event 12 is a release of ammonia out of the C-A-1 vessel vent stack due to a fire in the condenser 13 room. See RPP-48900 for the evaluation of the associated hazardous conditions. 14
15 • Fires. This accident involves building fires. The bounding event is a fire occurring in 16
the evaporator room or pump room. See RPP-48900 for the evaluation of the associated 17 hazardous conditions. 18
19 • Filtration Failures Leading To Unfiltered Releases. This accident involves releases 20
caused by a failure of the vessel ventilation system or the K1 ventilation system due to a 21 fire, overpressure transient, or filter crushing event involving the vessel ventilation 22 system high-efficiency particulate air (HEPA) filters or the K1 ventilation system HEPA 23 filters, as well as a subsequent unfiltered release. See RPP-48900 for the evaluation of 24 the associated hazardous conditions. 25
26 • Pump Room Sump Steam Jet Events. This accident involves an event where the 27
steam/waste discharge for the pump room sump steam jet pump J-B-1 is blocked and the 28 steam supply flows down the inlet side of the sump jet eductor and is injected into a 29 waste pool in the sump, causing the generation of waste aerosols due to entrainment or 30 bubble burst. See RPP-48900 for the evaluation of the associated hazardous conditions. 31
32 Bounding Accidents (Design Basis). The selection of bounding accidents for quantitative 33 analysis of radiological consequences in Section 3.4.2 is primarily based on the onsite 34 radiological consequences for the representative accidents above. The two representative 35 accidents with the highest onsite radiological consequences are the flammable gas accident 36 (detonation in the C-A-1 vessel) and the waste leak and misroute accident (fine spray leak during 37 a transfer using slurry pump P-B-2). 38 39 Quantitative analysis of offsite radiological consequences for flammable gas accidents and waste 40 leaks and misroutes are documented in Section 3.4.2.1 and Section 3.4.2.2, respectively. The 41 analysis of bounding accidents also includes natural events in Section 3.4.2.3. 42 43 3.3.2.3.1.1 References. 44 45 RPP-48900, 2017, 242-A Evaporator Hazard Evaluation Database Report, Rev. 0-D, 46
Washington River Protection Solutions LLC, Richland, Washington. 47
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3.3.2.3.2 Defense-in-Depth. This section summarizes the defense-in-depth features identified 1 from the hazard and accident analyses of the 242-A Evaporator. Defense-in-depth refers to a 2 safety philosophy for hazard control. It is based on building layers of defense against the 3 uncontrolled release of radioactive and other hazardous material so that no one layer by itself, no 4 matter how good, is completely relied upon for protection of the public, workers, and the 5 environment. This safety philosophy compensates for potential human and mechanical failures. 6 In accordance with the graded approach, there is no requirement to demonstrate any generic, 7 minimum number of layers of defense. In general, more layers of defense are identified for 8 higher risk accidents. Defense-in-depth features include safety structures, systems, components 9 (SSC), technical safety requirements (TSR), and other design and administrative features that 10 provide multiple layers of defense to prevent or mitigate potential hazardous conditions and 11 postulated accidents. For the 242-A Evaporator, there are no safety-class SSCs (see accident 12 analyses in Section 3.4.2). 13 14 Table 3.3.2.3.2-1 identifies the safety-significant SSCs and TSRs derived from the qualitative 15 analysis of representative accidents and associated hazardous conditions in Section 3.3.2.4. 16 These safety-significant SSC and TSR controls are derived based on the control decision criteria 17 and methodologies described in Section 3.3.1.5, except for supporting safety SSCs and TSRs 18 which are derived from Chapter 4. Controls are identified for potential hazardous conditions that 19 meet the applicable criteria (based on frequency and consequences) for the offsite public and 20 onsite worker and/or that are estimated to have significant facility worker consequences (i.e., a 21 prompt worker fatality, serious injuries, or significant radiological or chemical exposures to 22 workers). The safety functions of the safety-significant SSCs and specific administrative 23 controls (SAC) are defined in Section 3.3.2.4 with details of each safety-significant SSC and 24 SAC provided in Chapter 4.0 (i.e., safety function, system [or SAC] description, functional 25 requirements, system [or SAC] evaluation, and controls). Other TSRs (i.e., Key Elements of 26 Administrative Controls [AC]) are also derived and described in Section 3.3.2.4. 27 28 Other 242-Evaporator design and administrative features that are not safety SSCs or TSRs 29 provide additional defense-in-depth. These non-safety SSCs and non-TSR administrative 30 features are summarized in Table 3.3.2.3.2-2. These other defense-in-depth features are 31 identified based on the criteria and methodology described in Section 3.3.1.5, which includes a 32 review of potential hazardous conditions that exceed the guidelines for the onsite worker 33 (i.e., > 100 rem total effective dose [TED] and/or > Protective Action Criteria [PAC]-3) or are 34 estimated to have significant facility worker consequences. During the control selection process, 35 defense-in-depth features are also identified for other potential hazardous conditions that do not 36 exceed the guidelines for the onsite worker and do not have significant facility worker 37 consequences, but warrant additional defense-in-depth. 38 39 In addition to the non-safety SSCs and non-TSR administrative features summarized in 40 Table 3.3.2.3.2-2, the safety management programs described in Chapters 6.0 through 17.0 are 41 applied at the 242-A Evaporator, and through normal implementation of the programs, provide 42 additional defense-in-depth for multiple hazards. 43
44 Table 3.3.2.3.2-3 illustrates the safety SSCs, TSRs, and other defense-in-depth features for the 45 potential hazardous conditions evaluated in Section 3.3.2.4. As demonstrated in 46
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Table 3.3.2.3.2-3, the defense-in-depth features provided for the identified 242-A Evaporator 1 hazards are commensurate with the risk posed to the public, workers, and the environment, and 2 acceptably prevent or mitigate uncontrolled releases of radioactive and other hazardous material. 3 4 3.3.2.3.2.1 Implementation of Table 3.3.2.3.2-2 Defense-in-Depth Features. The non-safety 5 SSCs and non-TSR administrative features listed in Table 3.3.2.3.2-2 are managed by the Tank 6 Operations Contractor (TOC) through procedures, standards, and change control processes. In 7 addition, some of the non-safety SSCs and non-TSR administrative features are managed by 8 safety management programs which are subject to external regulatory agencies 9 (e.g., environmental management program). The citation of a defense-in-depth feature in 10 Table 3.3.2.3.2-2 is not intended to impose any additional requirements on the feature beyond 11 those already imposed by the controlling safety management program or the applicable 12 procedures, standards, and change control processes. Because of the importance of these features, 13 elimination of any defense-in-depth feature listed in Table 3.3.2.3.2-2 requires approval of the 14 TOC Plant Review Committee. Waiving of individual defense-in-depth features is allowed on a 15 case-by-case basis with concurrence of the Production Operations Manager (or equivalent). 16 17 3.3.2.3.2.2 References. 18 19 ARP-T-601-014, Respond to Steam Condensate Graphic #14 Alarms at the 242-A Evaporator, 20
as amended, Washington River Protection Solutions LLC, Richland, Washington. 21 22 ARP-T-601-023, Respond to Radiation Monitoring K1 Ventilation Graphic #23 Alarms at the 23
242-A Evaporator, as amended, Washington River Protection Solutions LLC, Richland, 24 Washington. 25
26 ARP-T-601-044, Respond to IX-D-1 and RC-3 Graphic #44 Alarms at the 242-A Evaporator, as 27
amended, Washington River Protection Solutions LLC, Richland, Washington. 28 29 OSD-T-151-00012, Operating Specifications for the 242-A Evaporator, as amended, 30
Washington River Protections Solutions, LLC, Richland, Washington. 31 32 TF-AOP-EVAP-004, Response to 242-A Evaporator Loss of K1 Ventilation System, as amended, 33
Washington River Protection Solutions LLC, Richland, Washington. 34 35 TFC-ESHQ-RP_ARP-C-01, Area Radiation Monitor Alarm Response, as amended, Washington 36
River Protection Solutions LLC, Richland, Washington. 37 38 TO-600-002, 242-A Evaporator Pre-Start Activities, as amended, Washington River Protection 39
Solutions LLC, Richland, Washington. 40 41 TO-600-005, 242-A Evaporator Operability Checks, as amended, Washington River Protection 42
Solutions LLC, Richland, Washington. 43 44 TO-600-030, Start Up 242 A Evaporator System, as amended, Washington River Protection 45
Solutions LLC, Richland, Washington. 46
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1 TO-600-060, Shut Down 242-A Evaporator System, as amended, Washington River Protection 2
Solutions LLC, Richland, Washington. 3 4 TO-620-020, Operate the 242-A Evaporator Ventilation System, as amended, Washington River 5
Protection Solutions LLC, Richland, Washington. 6 7 TO-650-140, Flush 242-A Evaporator Vessel, Recirculation Loop and De-Entrainer Pads, as 8
amended, Washington River Protection Solutions LLC, Richland, Washington. 9 10 WAC 173-303-640, “Tank Systems,” Washington Administrative Code, as amended. 11
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T3.3.2.3.2 1 Table 3.3.2.3.2-1. Summary of Safety Structures, Systems, and Components and
Technical Safety Requirements for Representative Accidents. (2 sheets)
No. Representative accident
Safety structures, systems, and components Technical safety requirementsa
1. Flammable gas accidents (Section 3.3.2.4.1)
Preventive SSCs SS: C-A-1 Vessel Flammable
Gas Control System SS: C-A-1 Vessel Waste
High Level Control System
Facility Worker Protection
SS: E-A-1 Reboiler (tube/tube sheet integrity)
SS: Backflow Prevention Devices (PSV-RW-3 and BFP-RW-11)
Preventive TSRs LCO: C-A-1 Vessel Flammable Gas
Control System LCO: C-A-1 Vessel Waste High Level
Control System
Facility Worker Protection SAC: Flammable Gas Controls for Waste
Feed Transfer Piping, Waste Slurry Transfer Piping, and C-A-1 Vessel Drain (Dump) Piping
Supporting TSRs
SAC: Evaporator and Pump Room Transient Combustible Material Controls
AC: C-A-1 Vessel Time to Lower Flammability Limit
AC: Ignition Controls
Other ACs AC: Emergency Response Actions
Following Facility Fires 2. Reserved for Future
Use -- --
3. Waste leaks and misroutes (Section 3.3.2.4.3)
Mitigative SSC SS: Pressure Relief Valve
(PSV-PB2-1)
Facility Worker Protection SS: C-A-1 Vessel Waste
High Level Control System
SS: E-A-1 Reboiler (tube/tube sheet integrity)
SS: Backflow Prevention Devices (PSV-RW-3 and BFP-RW-11)
Facility Worker Protection LCO: C-A-1 Vessel Waste High Level
Control System SAC: Evaporator and Pump Room Access
and Pump Room Cover Block Control
Supporting TSR
SAC: Evaporator and Pump Room Transient Combustible Material Controls
Other AC
AC: Emergency Response Actions Following Facility Fires
Table 3.3.2.3.2-1. Summary of Safety Structures, Systems, and Components and Technical Safety Requirements for Representative Accidents. (2 sheets)
No. Representative accident
Safety structures, systems, and components Technical safety requirementsa
5. Natural events (Section 3.3.2.4.5)
Preventive SSCs SS: C-A-1 Vessel Seismic
Dump System SS: 242-A Building
Preventive TSRs LCO: C-A-1 Vessel Seismic Dump System
Supporting TSR
SAC: Evaporator and Pump Room Transient Combustible Material Controls
AC: Emergency Preparedness
Notes: aIn addition to the TSRs listed for each representative accident, AC: Safety Management Programs
establishes the TOC commitment to establish, maintain, and implement the safety management programs as described in Chapters 7.0 through 17.0; and AC: Waste Characteristics Controls protects the source term assumptions used in the accident analyses.
AC = administrative control. LCO = limiting condition for operation. SAC = specific administrative control. SS = safety-significant.
SSC = structures, systems, and components. TOC = Tank Operations Contractor. TSR = technical safety requirement.
1
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Table 3.3.2.3.2-2. Other Defense-In-Depth Features (Non-Safety SSCs and Non-TSR Administrative Features). (4 sheets)
1. Draining/Flushing Waste Feed Transfer Piping, Waste Slurry Transfer Piping, and C-A-1 Vessel Drain (Dump) Piping SMP Owner: Engineering Draining and/or flushing of the 242-A Evaporator waste feed transfer piping, waste slurry transfer piping, and C-A-1 vessel drain (dump) piping following use provides an additional layer of defense for a flammable gas deflagration in this piping, which could present a significant facility worker hazard or damage safety-significant pressure relief valve PSV-PB2-1. The draining and/or flushing activities perform the function of removing waste from the piping that could generate flammable gas. Requirements for draining and/or flushing of the 242-A Evaporator waste feed transfer piping, waste slurry transfer piping, and C-A-1 vessel drain (dump) piping following use are provided in TO-650-140, Flush 242-A Evaporator Vessel, Recirculation Loop and De-Entrainer Pads, TO-600-030, Start Up 242 A Evaporator System, and TO-600-060, Shut Down 242-A Evaporator System. 2. Area Radiation Monitor RIAS-AR-1 SMP Owner: Radiological Control Area radiation monitor (ARM) RIAS-AR-1 provides an additional layer of defense for a misroute of waste into process condensate tank TK-C-100. Waste in process condensate tank TK-C-100 could generate flammable gas that eventually accumulates to a concentration that reaches or exceeds the lower flammability limit (LFL). This flammable gas deflagration or detonation could result in significant onsite toxicological consequences and could pose a significant facility worker hazard. In addition, waste in process condensate tank TK-C-100 could pose a significant facility worker hazard from direct radiation. ARM RAIS-AR-1 monitors and provides indication of a waste misroute into the process condensate system with an alarm to operators via the monitoring and control system (MCS). Upon receipt of the alarm on the MCS, personnel are evacuated from the condenser room and access to the condenser room is restricted to prevent unauthorized entry until clearance is obtained from a health physics technician (HPT). If necessary, actions will also be initiated to reduce potential flammable gas hazards. Requirements for ARM RIAS-AR-1 functional testing to ensure operability are provided in TO-600-005, 242-A Evaporator Operability Checks. Requirements for operator response to MCS alarms from ARM-RIAS-AR-1 are provided in ARP-T-601-023, Respond to Radiation Monitoring K1 Ventilation Graphic #23 Alarms at the 242-A Evaporator, and TFC-ESHQ-RP_ARP-C-01, Area Radiation Monitor Alarm Response.
1
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Table 3.3.2.3.2-2. Other Defense-In-Depth Features (Non-Safety SSCs and Non-TSR Administrative Features). (4 sheets)
3. Process Condensate Radiation Monitor RC-3 SMP Owner: Radiological Control Radiation monitor RC-3 provides an additional layer of defense for a misroute of waste into the process condensate system (tank TK-C-100 and piping and components). Waste in process condensate tank TK-C-100 or the process condensate system piping and components could generate flammable gas that eventually accumulates to a concentration that reaches or exceeds the LFL. A flammable gas deflagration or detonation in the headspace of process condensate tank TK-C-100 could result in significant onsite toxicological consequences and could pose a significant facility worker hazard, while a flammable gas deflagration in the process condensate system piping and components could pose a significant facility worker hazard. In addition, waste in process condensate tank TC-C-100 could pose a significant facility worker hazard from direct radiation. Waste in the process condensate system could also pose a significant facility worker hazard from wetting by the contaminated condensate during process condensate sampling activities, because sampling is performed when the process condensate system is operating Radiation monitor RC-3 monitors and provides indication of a waste misroute into the process condensate system with an alarm to operators via the MCS. Upon receipt of the alarm on the MCS, investigations are undertaken to determine the magnitude of the waste misroute and personnel protective actions (which could include restricted access to the condenser room and/or limiting sampling activities) are implemented. If necessary, actions will also be initiated to reduce potential flammable gas hazards. Requirements for radiation monitor RC-3 functional testing to ensure operability are provided in TO-600-005. Requirements for operator response to MCS alarms from RC-3 are provided in ARP-T-601-044, Respond to IX-D-1 and RC-3 Graphic #44 Alarms at the 242-A Evaporator. 4. Steam Condensate Radiation Monitor RC-1 SMP Owner: Radiological Control Steam condensate radiation monitor RC-1 provides an additional layer of defense for a misroute of waste into the steam condensate system (steam condensate piping and components including steam condensate weir box TK-C-103). The misrouted waste within the steam condensate piping and components (except steam condensate weir box TK-C-103) could generate flammable gas that eventually accumulates to a concentration that reaches or exceeds the LFL. This flammable gas deflagration could pose a significant facility worker hazard. In addition, waste in steam condensate weir box TK-C-103 could pose a significant facility worker hazard from direct radiation. Waste in the steam condensate system could also pose a significant facility worker hazard during steam condensate sampling activities, because sampling is performed when the steam condensate system is operating. Radiation monitor RC-1 monitors and provides indication of a waste misroute into the steam condensate system with an alarm to operators via the MCS. Upon receipt of the alarm on the MCS, investigations are undertaken to determine the magnitude of the waste misroute and personnel protective actions (which could include restricted access to the condenser room and/or limiting sampling activities) are implemented. If necessary, actions will also be initiated to reduce potential flammable gas hazards. Requirements for RC-1 functional testing to ensure operability are provided in TO-600-005. Requirements for operator response to MCS alarms from RC-1 are provided in ARP-T-601-014, Respond to Steam Condensate Graphic #14 Alarms at the 242-A Evaporator, and TFC-ESHQ-RP_ARP-C-01.
1
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Table 3.3.2.3.2-2. Other Defense-In-Depth Features (Non-Safety SSCs and Non-TSR Administrative Features). (4 sheets)
5. Waste Slurry System Piping Integrity SMP Owner: Environmental Management The confinement integrity of the waste slurry transfer piping and the slurry pump P-B-2 casing provides an additional layer of defense for a fine spray leak within the pump room during a waste transfer using slurry pump P-B-2, which could result in significant onsite toxicological hazards. The slurry pump P-B-2 casing and waste slurry transfer piping provide confinement of the waste (slurry) during normal operations to prevent a release of waste. Environmental requirements and criteria for the slurry pump P-B-2 casing and waste slurry transfer piping from the pump discharge to the connection with tank farm primary piping are found in WAC 173-303-640, Tank Systems, Washington Administrative Code. These requirements include a system integrity assessment and independent qualified registered professional engineer (IQRPE) certification. 6. Secondary Confinement of Airborne Releases SMP Owner: Radiological Control The K1 ventilation system provides secondary confinement of airborne releases within the pump room as an additional layer of defense for a fine spray leak within the pump room during a waste transfer using slurry pump P-B-2, which could result in significant onsite toxicological hazards. The K1 ventilation system limits the quantity of hazardous material released to facility workers and onsite receptors by maintaining contaminated areas of the 242-A Evaporator at a negative pressure (relative to atmospheric) and filtering exhaust air through two stages of high-efficiency particulate air (HEPA) filtration before exhausting or venting air to the outdoors. Requirements for the startup, operation, and shut down of the K1 ventilation system, including checks to ensure confinement capability, are provided in TO-620-020, Operate the 242-A Evaporator Ventilation System. Requirements for responding to a loss of the K1 ventilation system, which can include initiating a shutdown of 242-A Evaporator process operations, are provided in TF-AOP-EVAP-004, Response to 242-A Evaporator Loss of K1 Ventilation System. 7. E-A-1 Reboiler Chemistry and Flush Requirements SMP Owner: Engineering E-A-1 reboiler chemistry and flush requirements provides an additional layer of defense for E-A-1 reboiler tube/tube sheet integrity that could be degraded by corrosion. The safety function of the E-A-1 reboiler is to provide confinement of waste (i.e., E-A-1 reboiler tube/tube sheet integrity). Waste chemistry controls inhibit halide-induced corrosion. Flushes remove waste deposits in local areas, preventing initiation of pitting/crevice corrosion where the chemistries may not be well controlled. E-A-1 reboiler chemistry and flush requirements are specified in OSD-T-151-00012, Operating Specifications for the 242-A Evaporator. Chemistry limits (minimum slurry pH and minimum nitrate/chloride ratio) are evaluated in the campaign process control plan. The reboiler flush limit is monitored via the campaign process memo. Notes: ARP-T-601-014, Respond to Steam Condensate Graphic #14 Alarms at the 242-A Evaporator, as amended,
Washington River Protection Solutions LLC, Richland, Washington. ARP-T-601-023, Respond to Radiation Monitoring K1 Ventilation Graphic #23 Alarms at the 242-A Evaporator,
as amended, Washington River Protection Solutions LLC, Richland, Washington. ARP-T-601-044, Respond to IX-D-1 and RC-3 Graphic #44 Alarms at the 242-A Evaporator, as amended,
Washington River Protection Solutions LLC, Richland, Washington. OSD-T-151-00012, Operating Specifications for the 242-A Evaporator, as amended, Washington River
Protections Solutions LLC, Richland, Washington.
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Table 3.3.2.3.2-2. Other Defense-In-Depth Features (Non-Safety SSCs and Non-TSR Administrative Features). (4 sheets)
TF-AOP-EVAP-004, Response to 242-A Evaporator Loss of K1 Ventilation System, as amended, Washington River Protection Solutions LLC, Richland, Washington.
TFC-ESHQ-RP_ARP-C-01, Area Radiation Monitor Alarm Response, as amended, Washington River Protection Solutions LLC, Richland, Washington.
TO-600-002, 242-A Evaporator Pre-Start Activities, as amended, Washington River Protection Solutions LLC, Richland, Washington.
TO-600-005, 242-A Evaporator Operability Checks, as amended, Washington River Protection Solutions LLC, Richland, Washington.
TO-600-030, Start Up 242 A Evaporator System, as amended, Washington River Protection Solutions LLC, Richland, Washington.
TO-600-060, Shut Down 242-A Evaporator System, as amended, Washington River Protection Solutions LLC, Richland, Washington.
TO-620-020, Operate the 242-A Evaporator Ventilation System, as amended, Washington River Protection Solutions LLC, Richland, Washington.
TO-650-140, Flush 242-A Evaporator Vessel, Recirculation Loop and De-Entrainer Pads, as amended, Washington River Protection Solutions LLC, Richland, Washington.
WAC 173-303-640, Tank Systems, Washington Administrative Code, as amended.
ARM = area radiation monitor. HEPA = high-efficiency particulate air (filter). HPT = health physics technician. IQRPE = independent qualified registered
professional engineer. LFL = lower flammability limit.
MCS = monitoring and control system. SMP = safety management program SSC = structures, systems, and components. TSR = technical safety requirement. WAC = Washington Administrative Code.
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1 Table 3.3.2.3.2-3. Defense-In-Depth Features for Potential Hazardous Conditions. (5 sheets)
No. Hazardous condition Safety structures, systems, and components Technical safety requirementsa Other defense-in-depth featuresb
1. Flammable gas accidents A. Flammable gas
deflagration or detonation in the C-A-1 vesselc
Preventive SSC SS: C-A-1 Vessel
Flammable Gas Control System
Preventive TSR LCO: C-A-1 Vessel Flammable Gas
Control System
Supporting TSRs SAC: Evaporator and Pump Room
Transient Combustible Material Controls
AC: C-A-1 Vessel Time to Lower Flammability Limit
Other ACs
AC: Emergency Response Actions Following Facility Fires
None selected
B. Flammable gas deflagration in waste feed transfer piping, waste slurry transfer piping, or C-A-1 vessel drain (dump) piping
None required Facility Worker Protection SAC: Flammable Gas Controls for
Waste Feed Transfer Piping, Waste Slurry Transfer Piping, and C-A-1 Vessel Drain (Dump) Piping
Supporting TSR
AC: Ignition Controls
The following design or administrative features provide defense-in-depth for this accident: • Draining/flushing waste feed transfer piping,
waste slurry transfer piping, and C-A-1 vessel drain (dump) piping
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Table 3.3.2.3.2-3. Defense-In-Depth Features for Potential Hazardous Conditions. (5 sheets)
No. Hazardous condition Safety structures, systems, and components Technical safety requirementsa Other defense-in-depth featuresb
C. Flammable gas deflagration or detonation in process condensate tank TK-C-100
Preventive SSC SS: C-A-1 Vessel Waste
High Level Control System
Preventative TSR LCO: C-A-1 Vessel Waste High
Level Control System
Supporting TSR SAC: Evaporator and Pump Room
Transient Combustible Material Controls
Other AC
AC: Emergency Response Actions Following Facility Fires
The following design or administrative features provide defense-in-depth for this accident: • Area radiation monitor (ARM) RIAS-AR-1 • Process condensate radiation monitor RC-3
D. Flammable gas deflagration in process condensate system piping and components (except process condensate tank TK-C-100)
Facility Worker Protection
SS: C-A-1 Vessel Waste High Level Control System
Facility Worker Protection LCO: C-A-1 Vessel Waste High
Level Control System
The following design or administrative features provide defense-in-depth for this accident: • Process condensate radiation monitor RC-3
E. Flammable gas deflagration in steam condensate weir box TK-C-103d
None required None required None selected
F. Flammable gas deflagration in steam condensate system piping and components (except steam condensate weir box TK-C-103)
Facility Worker Protection
SS: E-A-1 Reboiler (tube/tube sheet integrity)
None required The following design or administrative features provide defense-in-depth for this accident: • Steam condensate radiation monitor RC-1 • E-A-1 reboiler chemistry and flush requirements
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Table 3.3.2.3.2-3. Defense-In-Depth Features for Potential Hazardous Conditions. (5 sheets)
No. Hazardous condition Safety structures, systems, and components Technical safety requirementsa Other defense-in-depth featuresb
G. Flammable gas deflagration in raw water system
Facility Worker Protection
SS: Backflow Prevention Devices (PSV-RW-3 and BFP-RW-11)
None required None selected
2. Reserve for Future Use 3. Waste Leaks and Misroutes A. Fine spray leak during
waste transfer using slurry pump P-B-2
Mitigative SSC SS: Pressure Relief Valve
(PSV-PB2-1)
None required The following design or administrative features provide defense-in-depth for this accident: • Waste slurry system piping integrity • Secondary confinement of airborne releases
B. Waste leaks into the evaporator or pump rooms
None required Facility Worker Protection SAC: Evaporator and Pump Room
Access and Pump Room Cover Block Control
None selected
C. Misroute of waste from tank farms to the C-A-1 vessel
None required Facility Worker Protection SAC: Evaporator and Pump Room
Access and Pump Room Cover Block Control
None selected
D. Misroute of waste into the process condensate system
Facility Worker Protection
SS: C-A-1 Vessel Waste High Level Control System
Facility Worker Protection LCO: C-A-1 Vessel Waste High
Level Control System
Supporting TSR SAC: Evaporator and Pump Room
Transient Combustible Material Controls
Other AC
AC: Emergency Response Actions Following Facility Fires
The following design or administrative features provide defense-in-depth for this accident: • ARM RIAS-AR-1 • Process condensate radiation monitor RC-3
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Table 3.3.2.3.2-3. Defense-In-Depth Features for Potential Hazardous Conditions. (5 sheets)
No. Hazardous condition Safety structures, systems, and components Technical safety requirementsa Other defense-in-depth featuresb
E. Misroute of waste into the steam condensate system
Facility Worker Protection
SS: E-A-1 Reboiler (tube/tube sheet integrity)
None required The following design or administrative features provide defense-in-depth for this accident: • Steam condensate radiation monitor RC-1 • E-A-1 reboiler chemistry and flush requirements
F. Misroute of waste into the raw water system
Facility Worker Protection
SS: Backflow Prevention Devices (PSV-RW-3 and BFP-RW-11)
None required None selected
4. Natural Events A. Seismic event Preventive SSCs
SS: C-A-1 Vessel Seismic Dump System
SS: 242-A Building
Preventative TSRs LCO: C-A-1 Vessel Seismic Dump
System
Supporting TSR SAC: Evaporator and Pump Room
Transient Combustible Material Controls
AC: Emergency Preparedness
None selected
B. High wind, snow, ashfall
Preventive SSC SS: 242-A Building
None required None selected
Note: The hazardous conditions listed below do not require safety SSCs or TSR controls. The associated representative accident is described in Section 3.3.2.3.1.
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Table 3.3.2.3.2-3. Defense-In-Depth Features for Potential Hazardous Conditions. (5 sheets)
No. Hazardous condition Safety structures, systems, and components Technical safety requirementsa Other defense-in-depth featuresb
5. Fire A. Evaporator room and/or
pump room fire None required None required None selected
Notes:
aIn addition to the listed TSRs, AC: Waste Characteristic Controls protects the source term assumptions used in the estimated consequence evaluation of the hazardous condition.
bIn addition to the specific other defense-in-depth features identified in the table, AC: Safety Management Programs establishes the TOC commitment to establish, maintain, and implement the safety management programs as described in Chapters 7.0 through 17.0.
cThe C-A-1 vessel includes the E-A-1 reboiler and the recirculation line. dThe design of the steam condensate weir box TK-C-103 cover, which provides splash protection but does not trap flammable gas, eliminates the
flammable gas deflagration hazard in the weir box. AC = administrative control. ARM = area radiation monitor. LCO = limiting condition for operation. SS = safety significant.
SAC = specific administrative control. SSC = structures, systems, and components. TSR = technical safety requirement. TOC = Tank Operation Contractor.
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3.3.2.3.3 Worker Safety. The full suite of safety-significant systems, structures, and 1
components (SSC) and technical safety requirements (TSR) are identified in Table 3.3.2.3.2-1, 2
and some of these controls are specifically identified for facility worker protection. In addition, 3
facility workers are protected from the uncontrolled release of radioactive and other hazardous 4
material by the safety-significant SSCs and TSRs derived for the protection of onsite workers 5
(i.e., potential hazardous conditions whose consequences exceed 100 rem or Protective Action 6
Criteria [PAC]-3). Thus, there are SSCs and specific administrative controls (SAC) that are 7
identified as mitigative or preventive SSCs or SACs in Table 3.3.2.3.2-1 for the protection of the 8
onsite worker for certain hazardous conditions that also protect against significant facility worker 9
hazards (hazards that result in prompt worker fatality or serious injury or significant radiological 10
or chemical exposure) for other hazardous conditions. 11
12
The safety-significant SSCs shown below were developed specifically for protection of the 13
facility worker. 14
15
• E-A-1 Reboiler (tube/tube sheet integrity) 16
• Backflow Prevention Devices (PSV-RW-3 and BFP-RW-11) 17
18
In addition, the following safety-significant SSCs selected to prevent or mitigate onsite hazards 19
also protect facility workers from significant hazards. 20
21
• C-A-1 Vessel Flammable Gas Control System 22
• C-A-1 Vessel Waste High Level Control System 23
• C-A-1 Vessel Seismic Dump System 24
25
The SACs shown below were developed specifically for protection of the facility worker. 26
27
• Evaporator and Pump Room Access and Pump Room Cover Block Control 28
• Flammable Gas Controls for Waste Feed Transfer Piping, Waste Slurry Transfer Piping, 29
and C-A-1 Vessel Drain (Dump) Piping 30
31
In accordance with the guidelines in DOE-STD-3009-94, Preparation Guide for U.S. 32
Department of Energy Nonreactor Nuclear Facility Documented Safety Analyses, and 33
DOE-STD-1027-92, Hazard Categorization and Accident Analysis Techniques for Compliance 34
with DOE Order 5480.23, Nuclear Safety Analysis Reports, occupational hazards that are 35
identified in the hazard analysis and that are regulated by U.S. Department of Energy 36
(DOE)-prescribed occupational safety and health regulations, standards, requirements, and 37
guidelines are segregated (i.e., screened) from non-routine hazards and are not evaluated further 38
(see Section 3.3.1.4). 39
40
These occupational hazards are addressed by DOE-prescribed safety and health programs 41
including the Radiological Control program described in Chapter 7.0 and the Industrial Safety 42
and the Industrial Hygiene programs described in Chapter 8.0. Note that the Occupational Safety 43
and Health Administration (OSHA) rule 29 CFR 1910.119, “Process Safety Management of 44
Highly Hazardous Chemicals,” does not apply to 242-A Evaporator nonradiological (chemical) 45
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hazards (i.e., 242-A Evaporator chemical inventories do not exceed the threshold quantities 1
specified in 29 CFR 1910.119). 2
3
3.3.2.3.3.1 References. 4 5
29 CFR 1910.119, “Process Safety Management of Highly Hazardous Chemicals,” Code of 6
Federal Regulations, as amended. 7
8
DOE-STD-1027-92, 1997, Hazard Categorization and Accident Analysis Techniques for 9
Compliance with DOE Order 5480.23, Nuclear Safety Analysis Reports, Change 10
Notice No. 1, U.S. Department of Energy, Washington, D.C. 11
12
DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor 13
Nuclear Facility Documented Safety Analyses, Change Notice No. 3, U.S. Department of 14
Energy, Washington, D.C. 15
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3.3.2.3.4 Environmental Protection. The hazard evaluation of 242-A Evaporator included the 1
qualitative assessment of the environmental consequences from potential uncontrolled releases of 2
radioactive and other hazardous material. The environmental consequence levels, E0, E1, E2, 3
and E3 are defined in Section 3.3.1. Uncontrolled releases of large amounts of radioactive and 4
other hazardous material to the environment outside the facility boundaries are designated E3 or 5
E2. 6
7
No releases with an E3 consequence level were identified. Three hazardous conditions with E2 8
consequence levels were identified. 9
10
• Flammable gas deflagration or detonation in the C-A-1 vessel 11
• Flammable gas deflagration or detonation in process condensate tank TK-C-100 12
• Fine spray leak during waste transfer using slurry pump P-B-2 13
14
For these hazardous conditions, it was determined that the safety-significant structures, systems, 15
and components (SSC) and technical safety requirements (TSR) selected to protect the onsite and 16
facility workers also protect the environment (see Sections 3.3.2.3.2). The additional 17
defense-in-depth features identified in Section 3.3.2.3.2 provide additional environmental 18
protection. 19
20
Other E3/E2 hazardous conditions not involving radioactive material are possible. These include 21
the release of fuel oil or caustic materials. Such environmental hazards are managed by Tank 22
Operations Contractor (TOC) programs, including Environmental Management and Industrial 23
Hygiene programs, which specifically address these potential releases. 24
25
Environmental protection includes compliance with applicable environmental regulations and 26
programs to change the state of tank waste to reduce the risk of environmental releases. These 27
include the following. 28
29
• Regulatory Compliance. The tank farms (including the 242-A Evaporator) are operated 30
in accordance with applicable environmental regulations that address solid wastes, 31
hazardous materials, water quality, air quality, spill reporting, and transportation. The list 32
of the applicable regulations and a description of the tank farm programs (which are also 33
applicable to the 242-A Evaporator) are contained in Chapter 9.0. 34
35
• Programs. Programs are in place to retrieve and close single-shell tanks (SST), retrieve 36
double-shell tank (DST) waste, operate the 242-A Evaporator to maximize the storage 37
space in the DSTs, perform environmental restoration of contaminated sites, and provide 38
environmental monitoring of the Hanford Site and surrounding environment. 39
40
• Agreements. As part of the execution of the programs listed above, negotiations 41
between the State of Washington Department of Ecology (Ecology), the Department of 42
Energy (DOE) Office of River Protection (ORP), and the TOC are conducted so that 43
agreement may be reached regarding required environmental design and operational 44
features. These agreements are documented via letters received from Ecology, and 45
through Ecology approval of Tank Waste Retrieval Work Plans (previously known as 46
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retrieval project Functions & Requirements documents), as required in the Hanford 1
Federal Facility Agreement and Consent Order (Ecology et al. 1989). 2
3
In summary, design and operational features exist as part of the 242-A Evaporator safety basis 4
and other TOC programs (e.g., the Environmental Management Program) that prevent or 5
mitigate the consequences of large, uncontrolled radioactive and other hazardous material 6
releases to the environment. 7
8
3.3.2.3.4.1 References. 9 10
Ecology, EPA, and DOE, 1989, Hanford Federal Facility Agreement and Consent Order, as 11
amended, Washington State Department of Ecology, U.S. Environmental Protection 12
Agency, and U.S. Department of Energy, Olympia, Washington. 13
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3.3.2.3.5 Planned Design and Operational Safety Improvements. The following design and 1 operational safety improvements have been identified from either the hazard and accident 2 analyses of the 242-A Evaporator and its operations or the development and evaluation of 3 safety-significant structures, systems, and components (SSC) and specific administrative controls 4 (SAC) in Chapter 4.0. 5 6 Design/Operational Improvement 1: Complete 7 8 Design/Operational Improvement 2: The safety-significant C-A-1 vessel flammable gas 9 control system is not designed to fail safe in the event of a facility fire (see Section 4.4.1). The 10 safety-significant C-A-1 vessel waste high level control system is also not designed to fail safe in 11 the event of a facility fire (see Section 4.4.2). In the event of a facility fire that requires either of 12 these systems to actuate to prevent an accident, these systems may not be able to perform their 13 required safety functions. As part of a planned upgrade, design changes will be implemented to 14 ensure that the safety-significant C-A-1 vessel flammable gas control system and the 15 safety-significant C-A-1 vessel waste high level control system fail safe in the event of a facility 16 fire. This upgrade will be completed by September 30, 2019. 17 18 Design/Operational Improvement 3: The safety-significant C-A-1 vessel seismic dump 19 system is not automatically initiated upon detection of a seismic event, but is manually initiated 20 by an emergency stop button following seismic events that could cause loss of C-A-1 vessel 21 vacuum and purge air flow or the overflow of waste from the C-A-1 vessel into the process 22 condensate system. Manual actuation of the C-A-1 vessel seismic dump system may not be 23 timely enough to perform the required safety functions (see Section 4.4.3). As part of a planned 24 upgrade, the C-A-1 vessel seismic dump system will be modified to automatically initiate upon 25 detection of a seismic event (e.g., a seismic switch). This upgrade will be completed by 26 September 30, 2019.27
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3.3.2.4 Hazard Evaluation Results for Representative Accidents. This section 1 summarizes the hazard evaluation of the representative accidents shown below. The complete 2 list of representative accidents is provided in Section 3.3.2.3.1. 3 4
9 The evaluation of these representative accidents provides a description of the postulated accident 10 scenario(s) and the following information. 11 12
• Estimated frequency, which is qualitative and reported as either “anticipated,” “unlikely,” 13 “extremely unlikely,” or “beyond extremely unlikely” (see Table 3.3.1.3-1.) 14
15 • Estimated consequences for the accident scenario(s) without controls which are based on 16
conservative quantitative and/or qualitative analyses and are reported in relation to the 17 applicable guideline as follows: 18
19 - Onsite radiological consequence: < 100 rem total effective dose (TED) or ≥ 100 rem 20
• Estimated consequences for the accident scenario(s) with controls (only applicable when 28 safety-significant structures, systems, and components [SSC] or specific administrative 29 controls [SAC] are credited with mitigating the consequences to the onsite worker) 30
31 • Safety-significant SSCs and the basis for selection (i.e., prevent or mitigate accidents that 32
exceed onsite guidelines, protect the facility worker, or are important contributors to 33 defense-in-depth) 34
35 • Technical safety requirements (TSR), which depending on the basis for selection, are 36
either: 37 38
- SACs (prevent or mitigate accidents that exceed onsite guidelines, protect the facility 39 worker, or protect an important initial condition assumed in the hazard analysis) 40
41 - Key elements of Administrative Controls (important contributors to defense-in-depth 42
or support SACs or LCOs) 43 44 The analyses of offsite radiological consequences are documented in Section 3.4.2 and, per these 45 analyses, no safety-class SSCs are required for the 242-A Evaporator. 46
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1 In addition to the TSRs identified for the representative accidents in the following sections, 2 Table 3.3.2.4-1 identifies one general TSR (waste characteristic control) that is not derived for a 3 specific representative accident. 4 5 The TSR on waste characteristics controls is required to ensure that the radiological and 6 toxicological source terms (i.e., unit-liter dose [ULD], unit sum-of-fractions [USOF], and 90Sr 7 and 137Cs concentrations) used in the accident analyses are protected. The method for 8 developing radiological source terms is described in RPP-5924, Radiological Source Terms for 9 Tank Farms Safety Analysis. The method for developing toxicological source terms is described 10 in RPP-30604, Tank Farms Safety Analyses Chemical Source Term Methodology. The safety 11 function of the waste characteristic control is to protect assumptions on waste characteristics 12 used to estimate accident consequences by ensuring that ULD, USOF, and 90Sr and 137Cs 13 concentrations are within the values used in the documented safety analysis (DSA). Additional 14 description of this control is provided in Section 5.5.3.4. 15 16 References. 17 18 HNF-15279, 242-A Evaporator Technical Safety Requirements, as amended, Washington River 19
Protection Solutions LLC, Richland, Washington. 20 21 RPP-5924, 2007, Radiological Source Terms for Tank Farms Safety Analysis, Rev. 5, 22
CH2M HILL Hanford Group, Inc., Richland, Washington. 23 24 RPP-30604, Tank Farms Safety Analyses Chemical Source Term Methodology, as amended, 25
Washington River Protection Solutions LLC, Richland, Washington. 26
27
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T3.3.2.4 1 Table 3.3.2.4-1. Summary of General Technical Safety Requirements for
242-A Evaporator Accidents. Technical safety requirement* Safety function Comment
Waste Characteristics Controls To protect assumptions on waste characteristics used to estimate accident consequences by ensuring that ULD, USOF, and 90Sr and 137Cs concentrations are within the values used in the DSA.
This TSR protects radiological and toxicological source term assumptions used in the accident analyses Radiological source terms are developed by the method described in RPP-5924 and placed on a configuration-controlled web location Toxicological source terms are developed by the method described in RPP-30604 and placed on a configuration-controlled web location
Notes:
*For the complete text of the controls summarized in this table refer to the latest revision of HNF-15279. HNF-15279, 242-A Evaporator Technical Safety Requirements, as amended, Washington River Protection
Solutions LLC, Richland, Washington. RPP-5924, 2007, Radiological Source Terms for Tank Farms Safety Analysis, Rev. 5, CH2M HILL Hanford
Group, Inc., Richland, Washington. RPP-30604, Tank Farms Safety Analyses Chemical Source Term Methodology, as amended, Washington
River Protection Solutions LLC, Richland, Washington. DSA = documented safety analysis. TSR = technical safety requirement. ULD = unit-liter dose. USOF = unit sum of fraction.
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3.3.2.4.1 Flammable Gas Accidents. Flammable gases, primarily hydrogen, are generated by 1 the waste that the 242-A Evaporator receives from the tank farms. If the concentration of a 2 flammable gas mixture reaches its lower flammability limit (LFL) and an ignition source is 3 present, a deflagration or detonation can occur with sufficient energy to release radioactive and 4 other hazardous materials to the environment. 5 6 Waste in the 242-A Evaporator is capable of generating flammable gas at a rate that depends on 7 the quantity of waste and its physical and chemical characteristics. Hydrogen is generated via 8 radiolysis of water and organics, thermolytic decomposition of organic compounds, and 9 corrosion. Radiolysis and thermolytic decomposition also generate ammonia. Additional 10 flammable gases (e.g., methane) are generated by chemical reactions between various 11 degradation products of organic chemicals present in the waste. Volatile or semivolatile organic 12 chemicals in the waste also produce organic vapors. Flammable gas generation, flammability 13 limits, ignition energy, and combustion pressure are described in RPP-13033, Tank Farms 14 Documented Safety Analysis, Section 3.3.2.4.1.1. 15 16 Waste-generated flammable gases can reach high concentrations in the 242-A Evaporator when 17 ventilation is limited. During normal operation when there is waste in the C-A-1 vessel, the 18 C-A-1 vessel is under vacuum and high temperature. Under these conditions, the C-A-1 vessel 19 headspace contains mostly water vapor with some ammonia, hydrogen, and methane; there is 20 very limited air; and thus no flammable gas concern. However, upon a loss of vacuum, air enters 21 the vessel and waste-generated flammable gases can accumulate in the C-A-1 vessel headspace 22 to concentrations exceeding the LFL. 23 24 Waste residuals may exist in waste transfer feed piping, waste transfer slurry piping, and the 25 C-A-1 vessel drain (dump) piping and, if sections of the piping are isolated, waste-generated 26 flammable gases can accumulate to concentrations exceeding the LFL. 27 28 Waste is normally not present in the process condensate system, steam condensate system, and 29 raw water system, but can be misrouted into these systems. (Note: Waste misroute scenarios are 30 described in Section 3.3.2.4.3). Waste in the process condensate system, steam condensate 31 system, and raw water system can generate and accumulate flammable gases to concentrations 32 exceeding the LFL. 33 34 The consequences of flammable gas accidents depend on the quantity (volume and 35 concentration) of the flammable gas. The consequences only exceed onsite toxicological 36 guidelines for flammable gas accidents in the C-A-1 vessel and process condensate tank 37 TK-C-100. An evaluation of the consequences for these postulated accidents is described in 38 RPP-48050, Technical Basis for Releases from Deflagration or Detonation in the 242-A 39 Evaporator. 40 41 Flammable gas hazards in waste transfer feed piping, waste transfer slurry piping, C-A-1 vessel 42 drain (dump) piping, process condensate piping and components (except tank TK-C-100), steam 43 condensate system piping and components, and raw water system piping and components, only 44 pose a significant facility worker hazard. 45 46
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The flammable gas accident scenarios in the C-A-1 vessel and process condensate tank 1 TK-C-100 are described in Sections 3.3.2.4.1.1 and 3.3.2.4.1.2, respectively. The significant 2 facility worker hazard scenarios are described in Section 3.3.2.4.1.3. Section 3.3.2.4.1.4 is a 3 summary of the required safety-significant structures, systems, and components (SSC); technical 4 safety requirements (TSR); and defense-in-depth features addressing these flammable gas 5 accidents and hazards. 6 7 3.3.2.4.1.1 Deflagration/Detonation in Evaporator C-A-1 Vessel. RPP-CALC-29700, 8 Flammability Analysis and Time to Reach Lower Flammability Limit Calculations for the 242-A 9 Evaporator, calculates the steady-state flammable gas concentration in the C-A-1 vessel 10 headspace. As shown in RPP-CALC-29700, flammable gas concentrations in excess of the LFL 11 can be reached under barometric breathing conditions, in which the only movement of air into or 12 out of the vessel is due to variations in atmospheric pressure. 13 14 Given a flammable gas concentration in excess of the LFL, a deflagration or detonation can 15 occur should an ignition source be present. The energy required to ignite hydrogen is known to 16 be quite low for a deflagration (on the order of 2 x 10-5 Joules). The direct initiation of a 17 detonation requires an ignition source of high energy, high power, or large size. However, a 18 deflagration-to-detonation transition can occur for special geometry conditions. An ignition 19 source is assumed to be present and ignite the flammable gas in the vessel headspace; a 20 detonation is conservatively assumed. The C-A-1 vessel is assumed to be damaged and waste 21 released to the atmosphere. 22 23 Table 3.3.2.4.1-1, “Summary of Frequency and Consequences for Flammable Gas Accidents 24 without Controls,” presents the frequency and consequences for the evaluated scenario assuming 25 no controls. The basis for these evaluation conclusions is summarized below. 26 27 Methodology. The quantity of waste released for flammable gas detonations in the headspace of 28 the C-A-1 vessel are calculated using the tri-nitro toluene (TNT) equivalent correlation from 29 DOE-HDBK-3010-94, Airborne Release Fractions/Rates and Respirable Fractions for 30 Nonreactor Nuclear Facilities. The consequence analysis is documented in RPP-48050. 31 32 Key Assumptions: 33 34
• The total volume for the C-A-1 vessel and extended vapor space is 41,856 gal (5,600 ft3) 35 (RPP-CALC-29700). The extended headspace includes piping and the primary 36 condenser. The volume of the effluent pathway after the primary condenser is small and 37 is neglected. The waste volume in the C-A-1 vessel is assumed to be 23,000 gal, which is 38 based on the C-A-1 vessel low-low level alarm and interlock and results in a reasonably 39 conservative extended headspace volume. At this waste fill level, the extended 40 headspace volume containing flammable gas is 18,856 gal (41,856 gal – 23,000 gal) or 41 7.14 x 104 L. 42
43 • The flammable gas is assumed to be a stoichiometric mixture of hydrogen and air 44
(i.e., 30% hydrogen by volume), at which the maximum explosive energy potential 45 occurs. RPP-CALC-29700 shows that the concentration can reach 30 vol% in about 46 30 days, assuming the waste volume in the C-A-1 vessel is 26,000 gal (the maximum 47
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operating level). (Note: RPP-48050 also includes a sensitivity analysis with 2,704 gal of 1 waste in the C-A-1 vessel. This sensitivity analysis, however, assumed 4% hydrogen by 2 volume [i.e., the LFL], which is conservative because RPP-CALC-29700 shows it takes 3 years to reach 100% of the LFL with 2,704 gallons of residual waste in the C-A-1 vessel 4 conservatively assuming zero ventilation, and that barometric breathing is sufficient to 5 prevent reaching 100% of the LFL. The consequences from this sensitivity analysis are 6 bounded by base case.) 7
8 • The waste density used in the TNT equivalent calculation is 1.3 g/mL, which is a 9
reasonably conservative low value for a waste supernatant that has high radiological and 10 toxicological source terms (unit-liter dose [ULD] and unit sum-of-fractions [USOF]) 11 values. 12
13 • The ULD and USOF for this analysis are based on the worst case double-shell tank 14
(DST) waste layers reported in the Best-Basis Inventory (BBI). This is reasonably 15 conservative given that the wastes stored in DSTs includes those that have been 16 processed through the 242-A Evaporator and concentrated to higher levels than planned 17 for future 242-A Evaporator operations. The bounding values may be based on different 18 waste tanks. (Note: These source term assumptions are protected by waste characteristic 19 controls – see Section 5.5.3.4.) The ULDs and USOFs assumed are: 20
21 Onsite liquids ULD = 1.0 x 103 Sv/L 22 Onsite solids ULD = 2.0 x 105 Sv/L 23 PAC-2 liquids USOF = 3.5 x 108 24 PAC-2 solids USOF = 3.5 x 108 25 PAC-3 liquids USOF = 1.2 x 107 26 PAC-3 solids USOF = 2.3 x 107 27
28 • Evaporator slurry is not expected to contain significant amounts of entrained solids. The 29
base case assumption is, therefore, 0 vol% solids. However, a solids content of up to 30 1 vol% is evaluated as a sensitivity analysis. 31
32 Frequency Determination. The frequency of a headspace deflagration in the C-A-1 vessel 33 without controls is qualitatively determined to be “anticipated.” This frequency is qualitatively 34 determined based on operating experience for loss of C-A-1 vessel vacuum. 35 36 Consequence Determination. Scoping calculations of the potential consequences from a 37 C-A-1 vessel headspace deflagration/detonation are documented in RPP-48050. Based on the 38 above key assumptions, the total amount of respirable material suspended and released by a 39 flammable gas detonation in the C-A-1 vessel is 45.6 L. For this release, the onsite radiological 40 consequence is < 100 rem, the offsite toxicological consequence is < Protective Action Criteria 41 (PAC)-2, and the onsite toxicological consequence is > PAC-3. Therefore, safety-significant 42 SSCs or TSRs are required to prevent or mitigate this postulated accident scenario. In addition, 43 it is qualitatively determined that a C-A-1 vessel headspace deflagration/detonation could result 44 in significant facility worker consequences (i.e., grievous injury or death to a facility worker due 45 to overpressure or physical impact from SSC failure [missiles], or from toxicological exposure 46
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exceeding PAC-3). Accordingly, safety-significant SSCs and/or TSRs are also required to 1 protect the facility worker. 2 3 3.3.2.4.1.2 Deflagration/Detonation in Evaporator Process Condensate Tank TK-C-100. In 4 this accident scenario, waste is misrouted (i.e., overflows) from the C-A-1 vessel into the process 5 condensate system and process condensate tank TK-C-100. C-A-1 vessel waste overflow is 6 caused by undetected/uncontrolled C-A-1 vessel waste level increase (e.g., loss of slurry out 7 operation while continuing to feed waste to the C-A-1 vessel). RPP-CALC-29700 calculates the 8 steady-state flammable gas concentration in process condensate tank TK-C-100 resulting from 9 the misroute of waste into process condensate tank TK-C-100. As shown in RPP-CALC-29700, 10 flammable gas concentrations in excess of the LFL can be reached under barometric breathing 11 conditions if waste from the C-A-1 vessel overflows into process condensate tank TK-C-100. 12 (Note: RPP-CALC-29700 also shows that flammable gas concentrations in excess of the LFL 13 cannot be reached under barometric breathing conditions from waste misroutes into process 14 condensate tank TK-C-100 due to boil-over of waste from the C-A-1 vessel caused by a sudden 15 increase in vacuum or carry-over of waste from the C-A-1 vessel caused by foaming [i.e., 16 insufficient waste misrouted into process condensate tank TK-C-100].) 17 18 Given a flammable gas concentration in excess of the LFL, a deflagration or detonation can 19 occur should an ignition source be present. The energy required to ignite hydrogen is known to 20 be quite low for a deflagration (on the order of 2 x 10-5 Joules). The direct initiation of a 21 detonation requires an ignition source of high energy, high power, or large size. However, a 22 deflagration-to-detonation transition can occur for special geometry conditions. An ignition 23 source is assumed to be present and ignite the flammable gas in the tank headspace; a detonation 24 is conservatively assumed. The tank is assumed to be damaged and waste released to the 25 atmosphere. 26 27 Table 3.3.2.4.1-1, “Summary of Frequency and Consequences for Flammable Gas Accidents 28 without Controls,” presents the frequency and consequences for the evaluated scenario assuming 29 no controls. The basis for these evaluation conclusions is summarized below. 30 31 Methodology. The quantity of waste released for flammable gas detonations in the headspace of 32 the C-A-1 evaporator vessel are calculated using the TNT equivalent correlation from 33 DOE-HDBK-3010-94. The consequence analysis is documented in RPP-48050. 34 35 Key Assumptions: 36 37
• The minimum waste fill fraction in process condensate TK-C-100 required to cause 38 flammable gas concentrations to exceed the LFL assuming barometric breathing is 39 between zero and 0.1 (see RPP-CALC-29700). Therefore, it is conservatively assumed 40 that the entire tank volume contains flammable gas. The volume of flammable gas, 41 therefore, is 17,800 gal or 6.74 x 104 L (RPP-CALC-29700). 42
43 • The flammable gas is assumed to be a stoichiometric mixture of hydrogen and air 44
(i.e., 30% hydrogen by volume). 45 46
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• The waste density used in the TNT equivalent calculation is 1.3 g/mL, which is a 1 reasonably conservative low value for a waste supernatant that has high radiological and 2 toxicological source terms (ULD and USOF) values. 3
4 • The ULD and USOF for this analysis are based on the worst case DST waste layers 5
reported in the BBI. The ULDs and USOFs assumed are: 6 7
Onsite liquids ULD = 1.0 x 103 Sv/L 8 Onsite solids ULD = 2.0 x 105 Sv/L 9 PAC-2 liquids USOF = 3.5 x 108 10 PAC-2 solids USOF = 3.5 x 108 11 PAC-3 liquids USOF = 1.2 x 107 12 PAC-3 solids USOF = 2.3 x 107 13
14 Frequency Determination. The frequency of a headspace deflagration in process condensate 15 tank TK-C-100 without controls is qualitatively determined to be “extremely unlikely." This 16 frequency is qualitatively determined based on a significant, undetected overflow of waste from 17 the C-A-1 vessel into process condensate tank TK-C-100, and the subsequent accumulation of 18 flammable gas to a concentration of above the LFL and an ignition source. 19 20 Consequence Determination. Scoping calculations of the potential consequences from a 21 headspace deflagration/detonation in process condensate tank TK-C-100 are documented in 22 RPP-48050. Based on the above key assumptions, the total amount of respirable material 23 suspended and released by a flammable gas detonation in process condensate tank TK-C-100 24 vessel is 43.1 L. For this release, the onsite radiological consequence is < 100 rem, the offsite 25 toxicological consequence is < PAC-2, and the onsite toxicological consequence is > PAC-3. 26 Therefore, safety-significant SSCs or TSR controls are required to prevent or mitigate this 27 postulated accident scenario. In addition, it is qualitatively determined that without controls a 28 process condensate tank TK-C-100 headspace deflagration/detonation could also result in 29 significant facility worker consequences (i.e., grievous injury or death to a facility worker due to 30 overpressure or physical impact from SSC failure [missiles], or from toxicological exposure 31 exceeding PAC-3). Accordingly, safety-significant SSCs and/or TSRs are also required to 32 protect the facility worker. 33 34 3.3.2.4.1.3 Additional Significant Facility Worker Hazards Due to Flammable Gas 35 Deflagrations. The hazard evaluation concluded that the following scenarios do not exceed 36 offsite or onsite guidelines, but do pose a significant facility worker hazard. Accordingly, safety-37 significant SSCs and/or TSRs are required to protect the facility worker. 38 39
• Deflagration in Waste Transfer Feed Piping, Waste Transfer Slurry Piping, and C-A-1 40 Vessel Drain (Dump) Piping. In this accident scenario, flammable gas generated by 41 residual waste in waste transfer feed piping, waste transfer slurry piping, or C-A-1 vessel 42 drain (dump) piping due to failure to flush piping after a waste transfer accumulates to a 43 concentration above the LFL; an ignition source is assumed. It is qualitatively 44 determined that a flammable gas deflagration in waste transfer feed piping, waste transfer 45 slurry piping, or C-A-1 vessel drain (dump) piping without controls could result in 46 significant facility worker consequences (i.e., grievous injury or death to a facility worker 47
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due to overpressure or physical impact from SSC failure [missiles]), if ignited while 1 workers were in the evaporator room, pump room, load-out and hot equipment storage 2 room, or loading room (by operation of installed equipment or during manned work 3 activities). Manned work activities are activities that can cause an uncontrolled ignition 4 source (e.g., errant spark) as a result of the use or manipulation of equipment or material 5 by personnel or human error. 6 7
• Deflagration in Process Condensate System Piping and Components. In this accident 8 scenario, waste is misrouted into the process condensate system due to the overflow of 9 waste from the C-A-1 vessel, the boil-over of waste from the C-A-1 vessel caused by a 10 sudden increase in vacuum (e.g., sudden closing of air bleed-in valve), or the carry-over 11 of waste from the C-A-1 vessel caused by foaming (e.g., insufficient anti-foam used). 12 Flammable gas generated from waste (i.e., contaminated process condensate) in process 13 condensate system piping and components accumulates to a concentration above the 14 LFL; an ignition source is assumed. It is qualitatively determined that a flammable gas 15 deflagration in process condensate system piping or components without controls could 16 result in significant facility worker consequences (i.e., grievous injury or death to a 17 facility worker due to overpressure or physical impact from SSC failure [missiles]). 18
19 • Deflagration in Steam Condensate System Piping and Components. This accident 20
scenario is the misroute of waste into the steam condensate system (i.e., contamination of 21 steam condensate) caused by a waste leak in an E-A-1 reboiler tube(s)/tube sheet and the 22 shell side (steam or air) pressure is below the tube side (waste) pressure in the reboiler 23 (an off-normal condition). Flammable gas generated from waste in steam condensate 24 system piping and components accumulates to a concentration above the LFL; an ignition 25 source is assumed. It is qualitatively determined that a flammable gas deflagration in 26 steam condensate system piping or components without controls could result in 27 significant facility worker consequences (i.e., grievous injury or death to a facility worker 28 due to overpressure or physical impact from SSC failure [missiles]). (Note: Flammable 29 gas accumulation above the LFL in the steam condensate weir box TK-C-103 is not 30 credible because the design of the weir box TK-C-103 cover, which provides splash 31 protection but does not trap flammable gas, eliminates the flammable gas deflagration 32 hazard.) 33
34 • Deflagration in the Raw Water System - In this accident scenario, waste is misrouted into 35
the raw water system due to (1) misroutes from the waste slurry sampler or (2) back-36 siphoning events from flush water connections. Flammable gas generated by waste in the 37 raw water system piping and components accumulates to a concentration above the LFL; 38 an ignition source is assumed. It is qualitatively determined that a flammable gas 39 deflagration in the raw water system without controls could result in significant facility 40 worker consequences (i.e., grievous injury or death to a facility worker due to 41 overpressure or physical impact from SSC failure [missiles]). 42
43 3.3.2.4.1.4 Summary of Safety-Significant Structures, Systems, and Components; 44 Technical Safety Requirement Controls; and Defense-in-Depth Features. Safety-significant 45 SSCs and TSRs have been selected to address the following hazards that either exceed onsite 46
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evaluation guidelines or pose a significant facility worker hazard as a result of a flammable gas 1 accident. 2 3
• Onsite toxicological and significant facility worker hazards due to flammable gas 4 deflagration or detonation in the C-A-1 vessel. 5
6 • Onsite toxicological and significant facility worker hazards due to flammable gas 7
deflagration or detonation in process condensate tank TK-C-100. Significant facility 8 worker hazards due to a flammable gas deflagration in process condensate system piping 9 or components. 10
11 • Significant facility worker hazards due to a flammable gas deflagration in waste transfer 12
feed piping, waste transfer slurry piping, or C-A-1 vessel drain (dump) piping. 13 14
• Significant facility worker hazards due to a flammable gas deflagration in steam 15 condensate system piping or components. 16
17 • Significant facility worker hazards due to a flammable gas deflagration in the raw water 18
system piping or components. 19 20 Safety-significant SSCs and TSRs for these accident scenarios are summarized below and are 21 listed in Table 3.3.2.4.1-2, "Summary of Safety Structures, Systems, and Components for 22 Flammable Gas Accidents," and Table 3.3.2.4.1-3, "Summary of Technical Safety Requirements 23 for Flammable Gas Accidents.” 24 25 Flammable Gas Deflagration or Detonation in the C-A-1 Vessel. The following safety-26 significant SSC is credited to prevent a flammable gas deflagration or detonation in the 27 C-A-1 vessel. 28 29
• C-A-1 Vessel Flammable Gas Control System. 30 31 The safety functions of the C-A-1 vessel flammable gas control system are: 32 33
1. To ensure C-A-1 vessel vacuum or purge air flow is maintained when the C-A-1 vessel 34 contains waste. Maintaining C-A-1 vessel vacuum or purge air flow when the C-A-1 35 vessel contains waste prevents a flammable gas accident in the C-A-1 vessel. 36
37 2. To limit the waste temperature in the C-A-1 vessel. Limiting the waste temperature in 38
the C-A-1 vessel protects the action completion times in the limiting condition for 39 operation (LCO) for the C-A-1 vessel flammable gas control system. 40
41 To accomplish these safety functions, the functional requirement of the C-A-1 vessel flammable 42 gas control system is to monitor C-A-1 vessel vacuum, purge air flow, and waste temperature. If 43
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C-A-1 vessel vacuum and purge air flow are not maintained when the C-A-1 vessel contains 1 waste or if waste temperature in the C-A-1 vessel exceeds the established limit: 2 3
• Feed pump 241-AW-P-102-1 is stopped 4 • Feed valve HV-CA1-1 is opened to drain the C-A-1 vessel 5 • Steam isolation valve HV-EA1-5 is closed 6 • Recirculation pump P-B-1 is stopped 7
8 In addition, after a time delay, dump valves HV-CA1-7 and HV-CA1-9 are opened to empty the 9 C-A-1 vessel. 10 11 The initial actions prevent a flammable gas accident by draining the C-A-1 vessel via the feed 12 line and limiting the temperature of the residual waste. The additional action of opening dump 13 valves HV-CA1-7 and HV-CA1-9 is a redundant method of preventing a flammable gas accident 14 by emptying the C-A-1 vessel. (See Section 4.4.1 for a description of the conditions for which 15 this functional requirement is met by the safety-significant C-A-1 vessel flammable gas control 16 system.) 17 18 The C-A-1 Flammable Gas Control System is implemented with a TSR LCO. 19 20
• LCO: C-A-1 Vessel Flammable Gas Control System. 21 22 The safety function of the LCO C-A-1 Vessel Flammable Gas Control System is to ensure 23 operability of the C-A-1 vessel flammable gas control system. 24 25 The following supporting control is identified as a TSR Administrative Control (AC) Key 26 Element (KE): 27 28
• KE: C-A-1 Vessel Time to Lower Flammability Limit. 29 30 The safety function of the KE C-A-1 Vessel Time to Lower Flammability Limit is to protect 31 assumptions used to develop action completion times in the LCO for the C-A-1 vessel flammable 32 gas control system. See Section 5.5.3.1. 33 34 No defense-in-depth features have been selected for the deflagration/detonation in the C-A-1 35 vessel. 36 37 Flammable Gas Deflagration or Detonation in Process Condensate Tank TK-C-100 and 38 Flammable Gas Deflagration in Process Condensate System Piping or Components. The 39 following safety-significant SSC is credited to prevent a flammable gas deflagration or 40 detonation in process condensate tank TK-C-100 and is selected to protect the facility worker 41 from a flammable gas deflagration in process condensate system piping and components. 42 43
• C-A-1 Vessel Waste High Level Control System. 44 45
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The safety function of the C-A-1 vessel waste high level control system is to prevent the 1 overflow, boil-over, and carry-over of waste from the C-A-1 vessel into the process condensate 2 system. Preventing the overflow of waste from the C-A-1 vessel into the process condensate 3 system prevents a flammable gas accident in process condensate tank TK-C-100 due to the 4 accumulation of flammable gas generated by waste in the tank. Preventing the overflow, 5 boil-over, and carry-over of waste from the C-A-1 vessel into the process condensate system 6 protects facility workers from a flammable gas accident in process condensate system piping and 7 components due to the accumulation of flammable gas generated by contaminated process 8 condensate in process condensate system piping or components. 9 10 To accomplish this safety function, the functional requirement of the C-A-1 vessel waste high 11 level control system is to (1) detect C-A-1 vessel waste high level based on the differential 12 pressure across the lower de-entrainment pad, and (2) on high level (i.e., high differential 13 pressure across the lower de-entrainment pad): 14 15
• Vacuum break valve HV-EC1-5 is opened. 16 • Feed pump 241-AW-P-102-1 is stopped. 17 • Feed valve HV-CA1-1 is opened to drain the C-A-1 vessel. 18
19 In addition, after a time delay, dump valves HV-CA1-7 and HV-CA1-9 are opened to empty the 20 C-A-1 vessel. 21 22 Opening vacuum break valve HV-EC1-5 stops boiling in the C-A-1 vessel, preventing boil-over 23 caused by a sudden increase in vacuum, and carry-over caused by foaming. Stopping feed pump 24 241-AW-P-102-1, opening feed valve HV-CA1-1, and opening dump valves HV-CA1-7 and 25 HV-CA1-9, after a time delay, prevents the overflow of waste from the C-A-1 vessel into the 26 process condensate system. (See Section 4.4.2 for a description of the conditions for which this 27 functional requirement is met by the safety-significant C-A-1 vessel waste high level control 28 system.) 29 30 The C-A-1 Vessel Waste High Level Control System is implemented with a TSR LCO. 31 32
• LCO: C-A-1 Vessel Waste High Level Control System. 33 34 The safety function of the LCO C-A-1 Vessel Waste High Level Control System is to ensure 35 operability of the C-A-1 vessel waste high level control system. 36 37 In addition, the following defense-in-depth features are selected to address these hazards due to 38 contaminated steam condensate. 39 40
• Defense-in-Depth: Area radiation monitor (ARM) RIAS-AR-1 as required by the 41 radiological control program. 42
43 • Defense-in-Depth: Process condensate radiation detection at RE-C-3 as required by the 44
radiological control program. 45 46
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Deflagration in Waste Transfer Feed Piping, Waste Transfer Slurry Piping, or C-A-1 1 Vessel Drain (Dump) Piping. The following TSR Specific Administrative Control (SAC) is 2 selected to protect the facility worker from a flammable gas deflagration in waste transfer feed, 3 waste transfer slurry piping, and C-A-1 vessel drain (dump) piping. 4 5
• SAC: Flammable Gas Controls for Waste Feed Transfer Piping, Waste Slurry Transfer 6 Piping, and C-A-1 Vessel Drain (Dump) Piping. 7
8 The safety function of the SAC Flammable Gas Controls for Waste Feed Transfer Piping, Waste 9 Slurry Transfer Piping, and C-A-1 Vessel Drain (Dump) Piping is to protect the facility worker 10 from a flammable gas deflagration due to the accumulation and ignition of flammable gases in 11 waste feed transfer piping, waste slurry transfer piping, or C-A-1 vessel drain (dump) piping. To 12 accomplish this safety function, the functional requirement of the Flammable Gas Controls for 13 Waste Feed Transfer Piping, Waste Slurry Transfer Piping, and C-A-1 Vessel Drain (Dump) 14 Piping SAC is to control potential ignition sources associated with installed equipment and 15 manned work activities involving waste feed transfer piping, waste slurry transfer piping, or 16 C-A-1 vessel drain (dump) piping. For manned work activities, ignition controls are not required 17 or may be discontinued if the flammable gas concentration inside the waste feed transfer piping, 18 waste slurry transfer piping, or C-A-1 vessel drain (dump) piping involved in the manned work 19 activity is verified to be ≤ 25% of the LFL. The use of 25% of the LFL as the control point 20 establishes a margin of safety. 21 22 The following supporting control is identified as a TSR AC Key Element. 23 24
• KE: Ignition Controls. 25 26 The safety functions of the KE Ignition Controls are: 27 28
1. To establish ignition control requirements consistent with applicable codes and standards, 29 including National Fire Protection Association (NFPA) requirements for control of 30 potential flammable gas ignition sources. 31
32 2. To evaluate installed equipment to ensure compliance with ignition control requirements 33
or provision of equivalent safety. 34 35
3. To evaluate manned work activities to determine the applicability of, and compliance 36 with, ignition control requirements or provision of equivalent safety. 37
38 This AC Key Element supports implementation of the ignition control requirements contained in 39 the above listed SAC. 40 41 In addition, design/procedures for draining waste feed transfer piping, waste slurry transfer 42 piping and C-A-1 vessel drain (dump) piping provide defense-in-depth by limiting the quantity 43 of flammable gas generating waste. 44 45
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Deflagration in Steam Condensate System Piping or Components. The following 1 safety-significant SSC is selected to protect the facility worker from a flammable gas 2 deflagration in steam condensate system piping or components. 3 4
• E-A-1 Reboiler. 5 6 The safety function of the E-A-1 Reboiler is to provide confinement of waste (i.e., E-A-1 7 reboiler tube/tube sheet integrity). Providing confinement of waste protects facility workers 8 from a flammable gas accident in the steam condensate system due to waste in the steam 9 condensate system resulting from an E-A-1 reboiler tube/tube sheet leak/failure (i.e., 10 accumulation of flammable gas generated by waste in the steam condensate system piping or 11 components). To accomplish this safety function, the functional requirement of the E-A-1 12 reboiler is no leakage of waste (leak tight pressure boundary). 13 14 In addition the following defense-in-depth feature is selected to address the hazards due to waste 15 in steam condensate system piping and components. 16 17
• Defense-in-Depth: Steam condensate radiation monitor RC-1 as required by the 18 radiological control program. 19
20 Deflagration in Raw Water System. The following safety-significant SSC is selected to 21 protect the facility worker from a flammable gas deflagration in the raw water system. 22 23
• Backflow prevention devices (PSV-RW-3 and BFP-RW-11). 24 25 The safety function of the backflow prevention devices PSV-RW-3 and BFP-RW-11 is to 26 prevent the backflow of waste into the raw water system. Preventing the backflow of waste into 27 the raw water system protects facility workers from a flammable gas accident (i.e., accumulation 28 of flammable gas generated by waste in the raw water system piping or components). To 29 accomplish this safety function, the functional requirement of the backflow prevention devices 30 (PSV-RW-3 and BFP-RW-11) is no backflow of waste (i.e., zero leak rate). 31 32 3.3.2.4.1.5 References. 33 34 Best-Basis Inventory (BBI). 35 36 DOE-HDBK-3010-94, 2000, Airborne Release Fractions/Rates and Respirable Fractions for 37
Nonreactor Nuclear Facilities, Change Notice No. 1, U.S. Department of Energy, 38 Washington, D.C. 39
40 HNF-15279, 242-A Evaporator Technical Safety Requirements, as amended, Washington River 41
Protection Solutions LLC, Richland, Washington. 42 43 RPP-13033, Tank Farms Documented Safety Analysis, as amended, Washington River Protection 44
Solutions LLC, Richland, Washington. 45 46
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RPP-48050, 2014, Technical Basis for Releases from Deflagration or Detonation in the 242-A 1 Evaporator, Rev. 1, Washington River Protection Solutions LLC, Richland, Washington. 2
3 RPP-CALC-29700, 2014, Flammability Analysis and Time to Reach Lower Flammability Limit 4
Calculations for the 242-A Evaporator, Rev. 3, Washington River Protection Solutions 5 LLC, Richland, Washington. 6
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T3.3.2.4.1 1 Table 3.3.2.4.1-1. Summary of Frequency and Consequences for
Flammable Gas Accidents without Controls.
Accident Frequency Onsite radiological Consequence
Offsite toxicological Consequence
Onsite toxicological Consequence
Deflagration or Detonation in C-A-1 Vessel
Anticipated (> 10-2 to < 10-1 per
year)
< 100 rem < PAC-2 > PAC-3
Deflagration or Detonation in Process Condensate Tank TK-C-100
Extremely Unlikely (> 10-6 to < 10-4 per
year)
< 100 rem < PAC-2 > PAC-3
Notes: PAC = Protective Action Criteria.
2
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Table 3.3.2.4.1-2. Summary of Safety Structures, Systems, and Components for Flammable Gas Accidents. (3 Sheets)
Structures, systems, and components
Safety classification Safety function Comments
C-A-1 vessel flammable gas control system
Safety-significant 1. To ensure C-A-1 vessel vacuum or purge air flow is maintained when the C-A-1 vessel contains waste. Maintaining C-A-1 vessel vacuum or purge air flow when the C-A-1 vessel contains waste prevents a flammable gas accident in the C-A-1 vessel.
2. To limit the waste temperature in the C-A-1 vessel. Limiting the waste temperature in the C-A-1 vessel protects action completion times in the C-A-1 Vessel Flammable Gas Control LCO.
The functional requirement is to monitor C-A-1 vessel vacuum, purge air flow, and waste temperature. If C-A-1 vessel vacuum and purge air flow are not maintained when the C-A-1 vessel contains waste or if waste temperature in the C-A-1 vessel exceeds the established limit: • Feed valve HV-CA1-1 is
opened to drain the C-A-1 vessel
• Feed pump 241-AW-P-102-1 is stopped
• Steam isolation valve HV-EA1-5 is closed
• Recirculation pump PB-1 is stopped
In addition, after a time delay, dump valves HV-CA1-7 and HV-CA1-9 are opened to empty the C-A-1 vessel. The initial actions prevent a flammable gas accident by draining the vessel via the feed line and limiting the temperature of the residual waste. The additional action of opening dump valves HV-CA1-7 and HV-CA1-9 is a redundant method of preventing a flammable gas accident by totally emptying the C-A-1 vessel. See Section 4.4.1
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Table 3.3.2.4.1-2. Summary of Safety Structures, Systems, and Components for Flammable Gas Accidents. (3 Sheets)
Structures, systems, and components
Safety classification Safety function Comments
C-A-1 vessel waste high level control system
Safety-significant To prevent the overflow, boil-over, and carry-over of waste from the C-A-1 vessel into the process condensate system. Preventing the overflow of waste from the C-A-1 vessel into the process condensate system prevents a flammable gas accident in process condensate tank TK-C-100 due to the accumulation of flammable gas generated by waste in the tank. Preventing the overflow, boil-over, and carry-over of waste from the C-A-1 vessel into the process condensate system protects facility workers from a flammable gas accident in process condensate system piping and components due to the accumulation of flammable gas generated by contaminated process condensate in process condensate system piping or components.
The functional requirement is to (1) detect C-A-1 vessel waste high level based on the differential pressure across the lower de-entrainment pad, and (2) on high level (i.e., high differential pressure across the lower de-entrainment pad): • Vacuum break valve
HV-EC1-5 is opened • Feed pump
241-AW-P-102-1 is stopped
• Feed valve HV-CA1-1 is opened to drain the C-A-1 vessel.
In addition, after a time delay, dump valves HV-CA1-7 and HV-CA1-9 are opened to empty the C-A-1 vessel. Opening vacuum break valve HV-EC1-5 stops boiling in the C-A-1 vessel, preventing boil-over caused by a sudden increase in vacuum and carry-over caused by foaming. Stopping feed pump 241-AW-P-102-1, opening feed valve HV-CA1-1, and opening dump valves HV-CA1-7 and HV-CA1-9, after a time delay, prevent the overflow of waste from the C-A-1 vessel into the process condensate system. See Section 4.4.2.
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Table 3.3.2.4.1-2. Summary of Safety Structures, Systems, and Components for Flammable Gas Accidents. (3 Sheets)
Structures, systems, and components
Safety classification Safety function Comments
E-A-1 reboiler Safety-significant To provide confinement of waste (i.e., E-A-1 reboiler tube/tube sheet integrity). Providing confinement of waste protects facility workers from a flammable gas accident in the steam condensate system due to waste in the steam condensate system resulting from an E-A-1 reboiler tube/tube sheet leak/failure (i.e., accumulation of flammable gas generated by waste in the steam condensate system piping or components).
The functional requirement is no leakage of waste (leak tight pressure boundary).
Backflow prevention devices (PSV-RW-3 and BFP-RW-11)
Safety-significant To prevent the backflow of waste into the raw water system. Preventing the backflow of waste into the raw water system protects facility workers from a flammable gas accident (i.e., accumulation of flammable gas generated by waste in the raw water system piping or components).
The functional requirement is no backflow of waste (i.e., zero leak rate).
Notes: LCO = limiting condition for operation.
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Table 3.3.2.4.1-3. Summary of Technical Safety Requirements for Flammable Gas Accidents. (2 sheets)
Technical safety requirement* Safety function Comment LCO: C-A-1 Vessel Flammable Gas Control System
To ensure the operability of the C-A-1 vessel flammable gas control system
See the safety function of the C-A-1 vessel flammable gas control system in Table 3.3.2.4.1-2 and Chapter 4.0. See also Section 5.5.2.1.
LCO: C-A-1 Vessel Waste High Level Control System
To ensure the operability of the C-A-1 vessel waste high level control system.
See the safety function of the C-A-1 vessel waste high level control system in Table 3.3.2.4.1-2 and Chapter 4.0. See also Section 5.5.2.2.
SAC: Flammable Gas Controls for Waste Feed Transfer Piping, Waste Slurry Transfer Piping, and C-A-1 Vessel Drain (Dump) Piping
To protect the facility worker from a flammable gas deflagration due to the accumulation and ignition of flammable gases in waste feed transfer piping, waste slurry transfer piping, or C-A-1 vessel drain (dump) piping.
The functional requirement is to control potential ignition sources associated with installed equipment and manned work activities involving waste feed transfer piping, waste slurry transfer piping, or C-A-1 vessel drain (dump) piping. For manned work activities, ignition controls are not required or may be discontinued if the flammable gas concentration inside the waste feed transfer piping, waste slurry transfer piping, or C-A-1 vessel drain (dump) piping involved in the manned work activity is verified to be ≤ 25% of the LFL. Ignition control requirements are determined in accordance with AC: Ignition Controls (see below).
AC: C-A-1 Vessel Time to Lower Flammability Limit
To protect assumptions used to develop the action completion times in LCO: C-A-1 Vessel Flammable Gas Controls.
See Section 5.5.3.1.
AC: Ignition Controls To establish ignition control requirements consistent with applicable codes and standards, including NFPA requirements for control of potential flammable gas ignition sources. To evaluate installed equipment to ensure compliance with ignition control requirements or provision of equivalent safety. To evaluate manned work activities to determine the applicability of, and ensure compliance with, ignition control requirements or provision of equivalent safety.
See Section 5.5.3.2.
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Table 3.3.2.4.1-3. Summary of Technical Safety Requirements for Flammable Gas Accidents. (2 sheets)
Notes:
*For the complete text of the controls summarized in this table refer to the latest revision of HNF-15279.
HNF-15279, 242-A Evaporator Technical Safety Requirements, as amended, Washington River Protection Solutions LLC, Richland, Washington.
AC = administrative control. LCO = limiting condition for operation. LFL = lower flammability limit. NFPA = National Fire Protection Association.
SAC = specific administrative control. 1
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3.3.2.4.3 Waste Leaks and Misroutes. Waste leaks (ranging from a fine spray to large break) 1 can occur within the 242-A Evaporator. Waste, under hydrostatic head only, exists in the C-A-1 2 vessel (includes the E-A-1 reboiler and recirculation line). Pumped (pressurized) waste exists in 3 the waste transfer feed line to the C-A-1 vessel from the tank farms when using feed pump 4 241-AW-P-102-1 and in the waste transfer slurry line to the tank farms from the C-A-1 vessel 5 when using slurry pump P-B-2. Waste could also be misrouted into the C-A-1 vessel when not 6 intended. In addition, waste could inadvertently be misrouted into interfacing systems including 7 the process condensate system, the steam condensate system, and the raw water system. 8 9 The hazards analysis performed for the 242-A Evaporator identified hazardous conditions 10 resulting in radioactive and other hazardous material releases due to waste leaks that could 11 exceed onsite evaluation guidelines or present a significant facility worker hazard. Such hazards 12 include waste leaks to the atmosphere that can pose a toxicological hazard to the onsite worker; 13 waste leaks that directly contact and wet a facility worker and could result in a significant 14 chemical (caustic) burn; and direct radiation hazards due to waste misroutes. 15 16 The potential onsite radiological and toxicological consequences of a waste leak vary based on 17 the driving pressure behind the leak. If the driving pressure is a pump (e.g., feed pump 18 241-AW-P-102-1, slurry pump P-B-2), the consequences are based on waste transfer leak 19 analyses included in RPP-13750, Waste Transfer Leaks Technical Basis Document. If the 20 driving pressure is hydrostatic head (e.g., waste in the C-A-1 vessel, waste recirculated by 21 recirculation pump P-B-1), the consequences are based on analyses in RPP-CALC-47411, 22 Technical Basis for Release Events due to Vessel Failure for the 242-A Evaporator Facility. 23 24 Analyses of bounding waste transfer pumps and bounding tank farm waste source terms 25 documented in RPP-13750 conclude that only pumped leaks that include direct pressurized spray 26 of aerosol into the air can have consequences that exceed evaluation guidelines, and only onsite 27 guidelines are exceeded. Such leaks involve fine cracks and high pressures (waste transfer 28 pumps whose head/flow performance exceeds the de minimus head/flow curve described in 29 RPP-13750, assuming radiological and toxicological source terms that bound all tank farm waste 30 layers as reported in the Best-Basis Inventory [BBI]) and are termed fine spray leaks. 31 32 The head/flow performance curve for feed pump 241-AW-P-102-1 is bounded by the de 33 minimus head/flow curve and, therefore, offsite and onsite radiological and toxicological 34 consequences are below evaluation guidelines for leaks that could occur in the 242-A Evaporator 35 during waste transfers to the 242-A Evaporator. 36 37 The head/flow performance curve for slurry pump P-B-2 is not bounded by the de minimus 38 head/flow curve and, therefore, specific analysis to address a fine spray leak involving slurry 39 pump P-B-2, assuming radiological and toxicological source terms that bound waste that can be 40 in the C-A-1 vessel, is presented below. 41 42 Waste leaks and misroutes into the process condensate system or the steam condensate system 43 could result in contaminated condensate and thus pressurized leaks of contaminated condensates 44 could occur due to the operation of process condensate pump P-C-100, process condensate 45 recycle pump P-C-106, and steam condensate sample pump P-RC-1. The head/flow curves for 46
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these pumps are below the de minimum curve and, therefore, pressurized leak consequences 1 could not exceed offsite or onsite radiological and toxicological evaluation guidelines. 2 3 The analysis in RPP-CALC-47411 concludes that the consequences for waste leaks involving 4 only hydrostatic head do not exceed offsite or onsite radiological or toxicological evaluation 5 guidelines. 6 7 Therefore, the only accident scenario that can exceed evaluation guidelines is a fine spray leak 8 involving a waste transfer using slurry pump P-B-2. This scenario and required controls are 9 described in Section 3.3.2.4.3.1. 10 11 Waste leaks from the C-A-1 vessel that can directly contact and wet a facility worker (worker 12 inadvertently in the pump or evaporator room when there is waste in the C-A-1 vessel and when 13 the leak occurs) could result in a significant chemical (caustic) burn. (Note: The direct radiation 14 hazard in the evaporator or pump rooms, when waste is expected to be present in the C-A-1 15 vessel, is an occupational hazard addressed by the radiological control safety management 16 program [see Chapter 7.0]). Waste misroutes (scenarios that allow waste to be in areas that are 17 not expected or intended to contain waste) could result in a significant facility worker hazard due 18 to direct radiation exposure or due to chemical (caustic) burns. These significant facility worker 19 hazards and required controls are described in Section 3.3.2.4.3.2. 20 21 3.3.2.4.3.1 Fine Spray Leak During a Waste Transfer Using Slurry Pump P-B-2. 22 23 3.3.2.4.3.1.1 Scenario Without Controls. Table 3.3.2.4.3-1, “Summary of Frequency and 24 Consequences for Waste Leak and Misroute Accidents without Controls,” presents the frequency 25 and consequences for a fine spray leak during a waste transfer using slurry pump P-B-2 26 assuming no controls. The basis for these conclusions is summarized below. 27 28 Methodology. The analysis methodology is described in detail in RPP-37897, Waste Transfer 29 Leak Analysis Methodology Description Document. The fine spray leak accident results from a 30 specific geometry (fine) crack in the slurry line within the 242-A Evaporator pump room. The 31 consequence analysis is documented in RPP-13750, Attachment A14. 32 33 Key Assumptions: 34 35
• The crack is assumed to have a width equal to the optimal crack width for producing fine 36 aerosol drops. The crack length is assumed to be a maximum of 3 in. 37
38 • It is assumed that a blockage exists downstream of the crack, and that there is minimal 39
pressure loss between the pump and the crack, thus maximizing the pressure available to 40 drive the spray release. 41
42 • The leak rate may be low and still exceed onsite radiological evaluation guidelines if the 43
pressure is high and, therefore, may not be readily identified. Therefore, the accident 44 duration is assumed to be 8 hr. 45
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• Unmitigated slurry pump P-B-2 performance is described in RPP-CALC-23897, VFD 1 Driven Induction Motor/Pump Performance Evaluation. The head versus flow data for a 2 waste specific gravity of 1.3 is used for this analysis because a waste specific gravity of 3 1.3 is selected to be representative of a double-shell tank (DST) supernatant with a low 4 viscosity (conservative for aerosolizing waste) and high unit-liter dose (ULD) and unit 5 sum-of-fractions (USOF) (concentration of dissolved chemicals), and the head/flow 6 performance at a waste specific gravity of 1.3 is more conservative than at a higher 7 specific gravity. (Note: The specific gravity value assumed has very little effect on 8 calculated consequences.) The slurry pump P-B-2 performance data is contained in 9 RPP-CALC-23897, Table 13. 10
11 • The leaked waste pool is assumed to form in the pump room sump and no gamma shine 12
is assumed to reach the onsite or offsite receptors. The consequences are only due to 13 aerosol releases. No aerosol attenuation is assumed to occur as the waste aerosols 14 migrate from where the aerosols are generated (pump room) until they exit the facility 15 (e.g., from the ventilation system stack). That is, gravity deposition of waste aerosol is 16 only assumed to occur once the aerosols are outside the 242-A Building in the 17 atmosphere. 18
19 • The radiological and toxicological source terms (ULD and USOF) for this analysis are 20
based on the worst case DST waste layers reported in the BBI. This is reasonably 21 conservative given that the wastes stored in DSTs includes those that have been 22 processed through the 242-A Evaporator and concentrated to higher levels than planned 23 for future 242-A Evaporator operations. The bounding values may be based on different 24 waste tanks. (Note: These source term assumptions are protected by Administrative 25 Control [AC] Key Element Waste Characteristics Controls [see Section 5.5.3.4].) The 26 ULDs and USOFs assumed are: 27
28 Onsite ULD for liquids = 1.0 x 103 Sv/L 29 Onsite ULD for solids = 2.0 x 105 Sv/L 30 PAC-2 USOF for liquids = 3.5 x 108 31 PAC-2 USOF for solids = 3.5 x 108 32 PAC-3 USOF for liquids = 1.2 x 107 33 PAC-3 USOF for solids = 2.3 x 107 34
35 • Evaporator slurry is not expected to contain significant amounts of entrained solids. The 36
base case assumption is, therefore, 0 vol% solids. However, a solids content of up to 37 1 vol% is evaluated as a sensitivity case. 38
39 Frequency. This scenario is qualitatively determined to have a frequency of “unlikely” because 40 the accident consequence requires a specific crack geometry that produces near optimal aerosol 41 generation. Most cracks are expected to have a width such that they would not be optimal 42 producers of fine aerosol spray. Fine spray radiological and toxicological consequences are very 43 sensitive to crack width, and decrease as crack width either increases or decreases from the 44 optimal value. Consequence from non-optimal cracks would be below onsite evaluation 45 guidelines. 46 47
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Consequences. The offsite toxicological consequence is less than Protective Action Criteria 1 (PAC)-2 and the onsite radiological consequence is less than 100 rem. However, the onsite 2 toxicological consequence is greater than PAC-3, and, therefore, safety-significant structures, 3 systems, and components (SSC) and/or Technical Safety Requirement (TSR) Specific 4 Administrative Controls (SAC) are required. 5 6 3.3.2.4.3.1.2 Summary of Safety-Significant SSCs and/or TSRs and Defense-in-Depth 7 Controls for Fine Spray Leak During a Waste Transfer Using Slurry Pump P-B-2. Safety-8 significant SSCs and TSRs selected for this accident scenario are listed in Table 3.3.2.4.3-2, 9 “Safety-Significant Structures, Systems, and Components for Waste Leak and Misroute 10 Accidents,” and Table 3.3.2.4.3-3, “Summary of Technical Safety Requirements for Waste Leak 11 and Misroute Accidents,” respectively. They are summarized below. 12 13 The following safety-significant SSC is credited to mitigate the fine spray leak during a waste 14 transfer using slurry pump P-B-2. 15 16
• Pressure relief valve PSV-PB2-1. 17 18 The safety function of pressure relief valve PSV-PB2-1 is to limit slurry pump P-B-2 discharge 19 pressure. Limiting the slurry pump P-B-2 discharge pressure decreases the consequences of a 20 fine spray leak. The functional requirement is to limit the slurry pump P-B-2 discharge pressure 21 to ≤ 275 lb/in2 gauge. 22 23 The consequence analysis in RPP-13750, Attachment A14, concludes that the onsite 24 toxicological consequence of a fine spray leak during a waste transfer using slurry pump P-B-2 is 25 less than PAC-3 if the pump discharge pressure is limited to ≤ 150 m (490 ft). To convert pump 26 discharge pressure in head to lb/in2 gauge, a representative waste specific gravity is required. For 27 fine spray leak accidents, a waste specific gravity of 1.3 is selected to be representative of a DST 28 supernatant with a low viscosity (conservative for aerosolizing waste) and high ULD 29 (concentration of dissolved chemicals). For the representative assumption of a waste specific 30 gravity of 1.3, this equates to a pressure of ≤ 275 lb/in2 gauge. Due to the conservative 31 (e.g., optimized fine crack, unmitigated pump performance) worst case waste source term 32 assumptions and the defense-in-depth features described below, no margin of safety is required. 33 34 No TSRs have been credited to prevent or mitigate fine spray leaks during a waste transfer using 35 slurry pump P-B-2. 36 37 The following non-safety-significant SSCs provide defense-in-depth. 38 39
• Defense-in-Depth: Waste slurry transfer piping integrity. The slurry pump P-B-2 casing 40 and waste slurry transfer piping (from the pump discharge to the connection with the tank 41 farm waste transfer primary piping system) meet the requirements of Washington 42 Administrative Code (WAC) 173-303-640, “Tank Systems” (i.e., system integrity 43 assessment and independent qualified registered professional engineer [IQRPE] 44 certification). 45
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• Defense-in-Depth: Secondary confinement of airborne releases (confinement ventilation 1 as required by the radiological control safety management program and Washington 2 Department of Ecology/Washington Department of Health). 3
4 3.3.2.4.3.1.3 Scenario with Controls. The consequences for a fine spray leak during a waste 5 transfer using slurry pump P-B-2, with the credited mitigative safety-significant SSCs, are shown 6 in Table 3.3.2.4.3-4, “Summary of Frequency and Consequences for Waste Leak Accidents with 7 Controls.” With the credited control the onsite toxicological consequence is mitigated to below 8 PAC-3. 9 10 3.3.2.4.3.2 Significant Facility Worker Hazards Due to Waste Leaks and Misroutes. The 11 hazard evaluation concluded that radiological and toxicological exposures due to waste aerosol 12 release from leaks do not pose a significant facility worker hazard. However, a leak does pose a 13 significant facility worker hazard due to chemical (caustic) burns if a waste leak occurred in a 14 normally occupied space, the worker is directly contacted (wetted) by the leak, and the waste is 15 highly caustic (i.e., has a pH ≥ 12.5). Such a leak would need to be a wetting spray/jet/stream 16 leak that is under some pressure and with a flow rate that can cause a significant wetting before 17 the worker can react to avoid the spray/jet/stream; not a pool. Waste feed to the 242-A 18 Evaporator will have a pH of ≥ 12.5, and thus waste in the C-A-1 vessel is assumed to have a pH 19 of ≥ 12.5. Process condensate, steam condensate, and raw water normally have a pH of < 12.5. 20 Therefore, a significant chemical burn hazard due to a leak in these interfacing systems would 21 require a prior misroute of waste into these systems. 22 23 3.3.2.4.3.2.1 Waste Leaks (Waste in Expected/Intended Systems). 24 25 Waste leak into the evaporator room or pump room (inadvertent occupation of the 26 evaporator or pump room). Two scenarios are postulated in the hazard analysis: (1) a worker 27 inadvertently enters the evaporator room or pump room when waste is already in the C-A-1 28 vessel and a leak occurs; or (2) a worker inadvertently enters the evaporator room or pump room 29 when waste or contaminated sump water (pH ≥ 12.5) is being jetted to the tank farms using the 30 pump room sump steam jet pump J-B-1 and a leak occurs. The following TSR SAC has been 31 selected to protect the facility worker. 32 33
• SAC: Evaporator and pump room access and pump room cover block control. 34 35 The safety function of the SAC is to restrict access to the evaporator room and pump room and 36 require the pump room cover blocks to be in place when waste is in the C-A-1 vessel or when the 37 pump room sump steam jet pump J-B-1 is not under administrative lock. Controlling access to 38 the evaporator room and pump room and controlling the removal of the pump room cover blocks 39 protects facility workers from waste leaks (i.e., chemical burns caused by wetting spray/jet/steam 40 leaks). Waste transfers from the pump room sump are prevented by placing the pump room 41 sump steam jet pump J-B-1 under administrative lock. The evaporator and pump room walls and 42 doors, and the pump room cover blocks prevent wetting spray/jet/steam leaks from reaching 43 normally occupied areas. No safety-significant SSC is required and no defense-in-depth features 44 are selected. 45 46
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3.3.2.4.3.2.2 Misroutes (Waste in Areas Where it is Not Expected/Intended). The hazard 1 analysis identified a number of scenarios that could result in a significant facility worker hazard 2 due to waste being in an area where it is not intended. These scenarios and required controls are 3 described below. 4 5 Misroute of Waste from Tank Farms to the C-A-1 Vessel. In this scenario, waste is 6 inadvertently routed from the tank farms to the C-A-1 vessel when workers are present 7 (e.g., during planned maintenance activities). Misroutes may occur due to inadvertent tank farm 8 waste transfer pump operation (i.e., feed pump 241-AW-P-102-1 or a pump that is physically 9 connected to the slurry line). Waste inadvertently being in the C-A-1 vessel when workers are in 10 the evaporator or pump room poses two significant hazards; (1) a significant chemical burn if a 11 leak occurs that could wet the worker; and (2) direct radiation exposure > 100 rem. The 12 following TSR SAC has been selected to protect the facility worker. 13 14
• SAC: Evaporator and pump room access and pump room cover block control. 15 16 The safety function of the SAC is to restrict access to the evaporator room and pump room and 17 require the pump room cover blocks to be in place when waste could be misrouted to the 242-A 18 Evaporator from tank farms. Controlling access to the pump room and evaporator room and 19 controlling removal of the pump room cover blocks protects facility workers from waste leaks 20 (i.e., chemical burns caused by wetting spray/jet/stream leaks) and direct radiation hazards. The 21 evaporator and pump room walls and doors, and the pump room cover blocks, prevent wetting 22 spray/jet/stream leaks from reaching normally occupied areas and provide shielding from direct 23 radiation. Waste misroutes to the 242-A Evaporator from tank farms are prevented by placing 24 feed pump 241-AW-P-102-1 under administrative lock and physically disconnecting slurry lines 25 SL-167 and SL-168 from the 242-A Evaporator. Slurry lines SL-167 and SL-168 are used to 26 transfer waste from the 242-A Evaporator to a receiver DST in tank farms, but waste could be 27 misrouted from tank farms to the 242-A Evaporator through these lines by a physically 28 connected DST waste transfer pump. 29 30 Misroute of Waste into the Process Condensate System. Waste might contaminate the 31 process condensate system due to: 32 33
• Waste overflow from the C-A-1 vessel caused by undetected/uncontrolled C-A-1 vessel 34 waste level increase (e.g., loss of slurry out operation while continuing to feed waste to 35 the C-A-1 vessel). 36
37 • Boil-over from the C-A-1 vessel caused by a sudden increase in vessel vacuum (e.g., 38
sudden closing of air bleed-in valve). 39 40
• Carry-over from the C-A-1 vessel caused by foaming (e.g., insufficient anti-foam used). 41 42 Accumulation of waste in process condensate tank TK-C-100 due to the overflow of waste from 43 the C-A-1 vessel could pose a significant facility worker hazard due to direct radiation 44 (i.e., > 100 rem). (Note: Boil-over or carry-over of waste from the C-A-1 vessel into process 45
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condensate tank TK-C-100 is insufficient to cause a direct radiation hazard (i.e., < 100 rem). 1 The direct radiation hazard from contaminated process condensate in other process condensate 2 system piping and components is also < 100 rem.) In addition, a worker could be wetted by the 3 contaminated process condensate during process condensate sampling activities and the 4 contaminated condensate could be at a pH ≥ 12.5, which is a significant facility worker hazard 5 due to chemical (caustic) burns. (Note: The process condensate system is within a 6 radiologically controlled area and, therefore, personnel are trained in SWIM [stop work, warn 7 others, isolate the area, and minimize exposure] actions. The frequency of a worker being wetted 8 by a random process condensate system leak, while there is contaminated condensate ≥ pH 12.5 9 in the system and a worker is in the near vicinity of the leak, such that the worker could not take 10 protective actions [e.g., SWIM], is judged to be “beyond extremely unlikely.”) 11 12 The following safety-significant SSC is selected. 13 14
• C-A-1 vessel waste high level control system. 15 16 The safety function of the C-A-1 vessel waste high level control system is to prevent the 17 overflow, boil-over, and carry-over of waste from the C-A-1 vessel into process condensate 18 system. Preventing the overflow of waste from the C-A-1 vessel into the process condensate 19 tank TK-C-100 protects facility workers from a direct radiation hazard. Preventing the overflow, 20 boil-over, and carry-over of waste from the C-A-1 vessel into the process condensate system 21 protects facility workers from chemical burn hazards during process condensate sampling 22 activities due to contaminated process condensate. 23 24 To accomplish this safety function, the functional requirement of the C-A-1 vessel waste high 25 level control system is to (1) detect C-A-1 vessel waste high level based on the differential 26 pressure across the lower de-entrainment pad, and (2) on high level (i.e., high differential 27 pressure across the lower de-entrainment pad): 28 29
• Vacuum break valve HV-EC1-5 is opened; 30 • Feed pump 241-AW-P-102-1 is stopped; and 31 • Feed valve HV-CA1-1 is opened to drain the C-A-1 vessel. 32
33 In addition, after a time delay, dump valves HV-CA1-7 and HV-CA1-9 are opened to empty the 34 C-A-1 vessel. 35 36 Opening vacuum break valve HV-EC1-5 stops boiling in the C-A-1 vessel, preventing boil-over 37 caused by a sudden increase in vacuum, and carry-over caused by foaming. Stopping feed pump 38 241-AW-P-102-1, opening feed valve HV-CA1-1, and opening dump valves HV-CA1-7 and 39 HV-CA1-9, after a time delay, prevents overflow of the C-A-1 vessel into the process condensate 40 system. (See Section 4.4.2 for a description of the conditions for which this functional 41 requirement is met by the safety-significant C-A-1 vessel waste high level control system.) 42 43 The C-A-1 Vessel Waste High Level Control System is implemented with a TSR LCO. 44 45
• LCO: C-A-1 Vessel Waste High Level Control System. 46
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1 The safety function of LCO C-A-1 Vessel Waste High Level Control System is to ensure the 2 operability of the C-A-1 vessel waste high level control system. 3 4 In addition, the following defense-in-depth features are selected to address these hazards due to a 5 misroute of waste into the process condensate system. 6 7
• Defense-in-Depth: Area radiation monitor (ARM) RIAS-AR-1 as required by the 8 radiological control safety management program. 9
10 • Defense-in-Depth: Process condensate radiation monitor RC-3 as required by the 11
radiological control safety management program. 12 13 Misroute of Waste into the Steam Condensate System. Waste might contaminate the steam 14 condensate system if a waste leak occurs in an E-A-1 reboiler tube(s)/tube sheet. Accumulation 15 of waste in the steam condensate weir box TK-C-103 could pose a significant facility worker 16 hazard due to a direct radiation hazard (i.e., > 100 rem). (Note: The direct radiation hazard from 17 contaminated steam condensate in the piping or other equipment is < 100 rem.) In addition, a 18 worker could be wetted by the contaminated condensate during steam condensate sampling 19 activities and the contaminated condensate could be at a pH ≥ 12.5, which is a significant facility 20 worker hazard due to chemical (caustic) burns. (Note: The steam condensate system is within a 21 radiologically controlled area, and, therefore, personnel are trained in SWIM actions. The 22 frequency of a worker being wetted by a random steam condensate system leak, while there is 23 contaminated condensate ≥ pH 12.5 in the system, and a worker is in the near vicinity of the 24 leak, such that the worker could not take protective actions [e.g., SWIM], is judged to be 25 “beyond extremely unlikely.”) 26 27 The following safety-significant SSC is selected to protect the facility worker. 28 29
• E-A-1 reboiler. 30 31 The safety function of the E-A-1 reboiler is to provide confinement of waste (i.e., E-A-1 reboiler 32 tube/tube sheet integrity). Providing confinement of waste protects facility workers from direct 33 radiation hazards and chemical burn hazards (i.e., skin contact with caustic waste) during steam 34 condensate sampling activities due to waste in the steam condensate system resulting from an 35 E-A-1 reboiler tube/tube sheet leak/failure. (Note: The direct radiation hazard is only from 36 waste misrouted into steam condensate weir box TK-C-103.) The functional requirement is no 37 leakage of waste (leak tight pressure boundary). 38 39 In addition the following defense-in-depth feature is selected to address these hazards due to 40 contaminated steam condensate. 41 42
• Defense-in-Depth: Steam condensate radiation monitor RC-1 as required by the 43 radiological control safety management program. 44
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Misroute of Waste into the Raw Water System. Waste might contaminate the raw water 1 system due to (1) misroutes from the waste slurry sampler, or (2) back-siphoning events from 2 flush water connections. The direct radiation hazard due to contaminated raw water is 3 < 100 rem. However, contaminated raw water may have a pH of ≥ 12.5 and pose a chemical 4 burn hazard if a worker could be wetted by the contaminated raw water (a leak occurred in the 5 raw water system while contamination causing a ≥ pH 12.5 was present). The pump room, 6 evaporator room, condenser room, and load-out and hot-equipment storage room are 7 radiologically controlled areas, and, therefore, personnel are trained in SWIM actions. The 8 frequency of a worker being wetted by a random raw water system leak, while there is 9 contaminated raw water ≥ pH 12.5 in the system, and a worker is in the near vicinity of the leak, 10 such that the worker could not take protective actions (e.g., SWIM), is judged to be “beyond 11 extremely unlikely.” Other areas, however, are not radiologically controlled areas (e.g., heating, 12 ventilation, and air conditioning [HVAC] room; aqueous makeup [AMU] room) and people may 13 be present who are not trained to take protective actions. Thus, a significant facility worker 14 hazard may be present due to a contaminated raw water leak into these non-radiologically 15 controlled areas. 16 17 The following safety-significant SSC is selected to protect the facility worker from the chemical 18 burn hazard. 19 20
• Backflow prevention devices (PSV-RW-3 and BFP-RW-11). 21 22 The safety function of the backflow prevention devices is to limit the backflow of waste into the 23 raw water system in a non-radiologically controlled area. Limiting the backflow of waste into 24 the raw water system in a non-radiologically controlled area protects facility workers from 25 chemical burns due to a wetting spray/jet/stream leak. 26 27 The functional requirement of the backflow prevention devices is to limit the backflow of waste 28 (i.e., leak rate) to ≤ 0.1 gal/min into non-radiologically controlled areas of the 242-A Evaporator. 29 (Note: Non-radiologically controlled areas of the 242-A Evaporator are all areas other than the 30 following rooms, which are radiologically controlled: pump room, evaporator room, condenser 31 room, and load-out and hot-equipment storage room.) The leak rate of ≤ 0.1 gal/min is judged 32 adequate to protect the facility worker from wetting spray/jet/stream leaks (see RPP-13033, Tank 33 Farms Documented Safety Analysis, Section 3.3.2.4.3, “Waste Transfer Leaks.”). Backflow 34 prevention device BFP-RW-11 limits the backflow of waste into the raw water supply to the 35 slurry sampler. Backflow prevention device PSV-RW-3 limits the back-siphoning of waste into 36 the raw water system from the raw water line connected to the C-A-1 vessel (dip tubes), dump 37 valves HV-CA1-7 and HV-CA1-9, and slurry flush valves HV-CA1-2 and HV-CA1-2A. 38 39 3.3.2.4.3.2.3 Definitions Used to Determine Waste Leak and Misroute Control 40 Applicability. The following definitions of waste transfer pump, physically connected, active 41 waste transfer pump, and under administrative lock are used to define the applicability of the 42 safety-significant SSCs and TSR waste leak and misroute controls listed in Tables 3.3.2.4.3-2 43 and 3.3.2.4.3-3. 44 45
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Active/Inactive. Active/inactive applies to waste transfer pumps. Active waste transfer pumps 1 are those that are capable of being used for waste transfers. Inactive waste transfer pumps are 2 those that have been permanently disabled from use (e.g., power supplies permanently 3 disconnected), such that waste transfers cannot be made without engineering change. 4 5 Physically Connected. Physically connected is a configuration where waste can flow between a 6 source (i.e., waste transfer pump, 242-A Evaporator [C-A-1] vessel) and piping or a waste 7 transfer-associated structure. 8 9 Physically connected piping includes waste transfer primary piping systems, hose-in-hose 10 transfer line (HIHTL) systems, and interfacing water system piping (e.g., service water, raw 11 water) that are not physically disconnected (see below). 12 13 Piping is not physically connected if it is physically disconnected as follows. 14 15
1. A blind flange is considered to physically disconnect piping on the side of the blind 16 flange that is downstream of the source of pressurized waste. 17
18 2. Two safety-significant waste transfer system isolation valves, independently verified to 19
be in the closed or block flow position, are considered to physically disconnect piping on 20 the downstream side of the second valve that is downstream of the source of pressurized 21 waste. 22
23 3. The inlet to a waste transfer pump is considered to be physically disconnected from the 24
waste transfer pump if the inlet cannot be pressurized by the pump (e.g., a centrifugal 25 pump located in a tank). (Note: The determination of whether the inlet to a waste 26 transfer pump can be pressurized shall consider reverse operation of the pump.) 27
28 Physically connected waste transfer-associated structures are those structures through which 29 physically connected piping runs or terminates. 30 31 Under Administrative Lock. Waste transfer pumps have the potential to operate at any time, 32 including inadvertent pump starts. Placing the waste transfer pump “under administrative lock” 33 allows operational flexibility by providing a means to remove and secure the motive force to the 34 waste transfer pump and preclude the possibility of inadvertent pump starts. 35 36 A waste transfer pump is “under administrative lock” when the motive force (i.e., electrical 37 power or steam) to the pump is removed and secured. Securing of the motive force is 38 accomplished through the use of an installed and engaged lock mechanism on the pump's motive 39 force supply or an alternate enforcement method. Examples of alternate enforcement include 40 stationing of an operator to maintain the motive force in a secure configuration, and physical 41 disconnection of the motive force from the pump (e.g., disconnecting a power supply by lifting 42 leads). 43 44
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The administrative locks are not associated with the TOC lock and tag program, which is a 1 separate program with a different purpose. In situations where lock and tag locks and 2 administrative locks are both required to be used, a spyder-type locking device may be used to 3 ensure proper configuration management of both devices. 4 5 Waste Transfer Pumps. Waste transfer pumps are pumps that have a suction source of waste in 6 a DST and 242-A Evaporator pumps P-B-2 and J-B-11. 7 8 3.3.2.4.3.3 References. 9 10 Best Basis Inventory (BBI). 11 12 HNF-15279, 242-A Evaporator Technical Safety Requirements, as amended, Washington River 13
Protection Solutions LLC, Richland, Washington. 14 15 RPP-13033, Tank Farms Documented Safety Analysis, as amended, Washington River Protection 16
Solutions LLC, Richland, Washington. 17 18 RPP-13750, 2013, Waste Transfer Leaks Technical Basis Document, Rev. 40, Washington River 19
Washington River Protection Solutions LLC, Richland, Washington. 23 24 RPP-CALC-47411, 2013, Technical Basis for Release Events due to Vessel Failure for the 25
242-A Evaporator Facility, Rev. 0, Washington River Protection Solutions LLC, 26 Richland, Washington. 27
Washington River Protection Solutions LLC, Richland, Washington. 30 31 WAC 173-303-640, “Tank Systems,” Washington Administrative Code, as amended. 32
1 242-A Evaporator pumps P-B-2 (slurry pump) or J-B-1 (pump room sump steam jet pump) are not waste transfer pumps when they can only transfer water, antifoaming agent, process condensate, inhibited water (e.g., water treated with hydroxide and/or nitrite used for corrosion control), etc., in the 242-A Evaporator C-A-1 vessel or pump room sump.
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T3.3.2.4.3 1 Table 3.3.2.4.3-1. Summary of Frequency and Consequences for
Waste Leak and Misroute Accidents Without Controls.
Accident Frequency Onsite radiological Consequence
Offsite toxicological Consequence
Onsite toxicological Consequence
Fine spray leak during a waste transfer using slurry pump P-B-2
Unlikely (>10-4 to ≤10-2
per year)
< 100 rem < PAC-2 > PAC-3
Notes:
PAC = Protective Action Criteria. 2
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Table 3.3.2.4.3-2. Safety-Significant Structures, Systems, and Components
for Waste Leak and Misroute Accidents. (2 sheets) Structures, systems, and
components Safety
classification Safety function Comments
Pressure relief valve (PSV-PB2-1)
Safety-significant To limit slurry pump P-B-2 discharge pressure.
Limiting the slurry pump P-B-2 discharge pressure decreases the consequences of a fine spray leak.
The functional requirement is to limit the slurry pump P-B-2 discharge pressure to ≤ 275 lb/in2 gauge.
C-A-1 vessel waste high level control system
Safety-significant To prevent the overflow, boil-over, and carry-over of waste from the C-A-1 vessel into the process condensate system. Preventing the overflow of waste from the C-A-1 vessel into process condensate tank TK-C-100 protects facility workers from a direct radiation hazard. Preventing the overflow, boil-over, and carry-over of waste from the C-A-1 vessel into the process condensate system protects facility workers from chemical burn hazards during process condensate sampling activities due to contaminated process condensate.
The functional requirement is to (1) detect C-A-1 vessel waste high level based on the differential pressure across the lower de-entrainment pad, and (2) on high level (i.e., high differential pressure across the lower de-entrainment pad): • Vacuum break valve
HV-EC1-5 is opened; • Feed pump
241-AW-P-102-1 is stopped; and
• Feed valve HV-CA1-1 is opened to drain the C-A-1 vessel.
In addition, after a time delay, dump valves HV-CA1-7 and HV-CA1-9 are opened to empty the C-A-1 vessel. Opening vacuum break valve HV-EC1-5 stops boiling in the C-A-1 vessel, preventing boil-over caused by a sudden increase in vacuum, and carry-over caused by foaming. Stopping feed pump 241-AW-P-102-1, opening feed valve HV-CA1-1, and opening dump valves HV-CA1-7 and HV-CA1-9, after a time delay, prevents the overflow of waste from the C-A-1 vessel into the process condensate system.
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Table 3.3.2.4.3-2. Safety-Significant Structures, Systems, and Components
for Waste Leak and Misroute Accidents. (2 sheets) Structures, systems, and
components Safety
classification Safety function Comments
E-A-1 reboiler Safety-significant To provide confinement of waste (i.e., E-A-1 reboiler tube/tube sheet integrity).
Providing confinement of waste protects facility workers from direct radiation hazards and chemical burn hazards (i.e., skin contact with caustic waste) during steam condensate sampling activities due to waste in the steam condensate system resulting from an E-A-1 reboiler tube/tube sheet leak/failure. (Note: The direct radiation hazard is only from waste misrouted into steam condensate weir box TK-C-103.)
The functional requirement is no leakage of waste (leak tight pressure boundary)
Backflow prevention devices (PSV-RW-3 and BFP-RW-11)
Safety-significant To limit the backflow of waste into the raw water system in a non-radiologically controlled area.
Limiting the backflow of waste into the raw water system in a non-radiologically controlled area protects facility workers from chemical burns due to a wetting spray/jet/stream leak.
The functional requirement is to limit the backflow of waste (i.e., leak rate) to ≤ 0.1 gal/min into non-radiologically controlled areas.
Note: Non-radiologically controlled areas of the 242-A Evaporator are all areas other than the following rooms, which are radiologically controlled: pump room, evaporator room, condenser room, and load-out and hot-equipment storage room.
1
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Table 3.3.2.4.3-3. Summary of Technical Safety Requirements for Waste Leak and Misroute Accidents.
Technical Safety Requirementa Safety function Comments LCO: C-A-1 vessel waste high level control system
To ensure the operability of the C-A-1 vessel waste high level control system.
See the safety function of the C-A-1 vessel waste high level control system in Table 3.3.2.4.3-2 and Chapter 4.0. See also Section 5.5.2.2.
SAC: Evaporator and pump room access and pump room cover block control
To restrict access to the pump room and evaporator room and require the pump room cover blocks to be in place when waste is in the C-A-1 vessel, waste could be misrouted to the 242-A Evaporator from tank farms, or when the pump room sump steam jet pump J-B-1 is not under administrative lock. Controlling access to the pump room and evaporator room and controlling the removal of the pump room cover blocks protects facility workers from waste leaks (i.e., chemical burns caused by wetting spray/jet/stream leaks) and direct radiation hazards.
Waste misroutes to the 242-A Evaporator from tank farms are prevented by placing 242-A Evaporator waste transfer feed pump 241-AW-P-102-1 under administrative lock and physically disconnecting slurry lines SL-167 and SL-168 from the 242-A Evaporator.
Waste transfers from the pump room sump are prevented by placing the pump room sump steam jet pump J-B-1 under administrative lock.
Notes:
aFor the complete text of the controls summarized in this table refer to the latest revision of HNF-15279. HNF-15279, 242-A Evaporator Technical Safety Requirements, Washington River Protection Solutions LLC,
Richland, Washington. LCO = limiting condition for operation. SAC = specific administrative control.
1
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Table 3.3.2.4.3-4. Summary of Frequency and Consequences for Waste Leak and Misroute Accidents With Controls.
Accident Frequency Onsite radiological Consequence
Offsite toxicological Consequence
Onsite toxicological Consequence
Fine spray leak during a waste transfer using slurry pump P-B-2
potential initiators for various categories of accidents. The consequence estimation and control 2
selection for external event-initiated accidents are covered in the sections that address the 3
specific category of accident initiated. This section describes the external event initiator 4
selection and provides the frequency basis for external event initiators. 5
6
External events that are potential 242-A Evaporator accident initiators are: 7
8
• Aircraft crash 9
• Vehicle accident 10
• Range fire 11
• Loss of site power 12
• Rail accident. 13
14
These events were identified as part of the hazard evaluation process detailed in Section 3.3.2. 15
16
The representative accidents initiated by external events are flammable gas accidents, and 17
filtration failures leading to unfiltered releases. 18
19
3.3.2.4.4.1 Aircraft Crash. Aircraft crash is a potential initiator of accidents that is required to 20
be analyzed per DOE-STD-3014-2006, Accident Analysis for Aircraft Crash into Hazardous 21
Facilities. This standard is applicable to all facilities containing significant quantities of 22
radioactive or hazardous chemical materials. For the purposes of this standard, facilities 23
categorized as Hazard Category 2 per the methodology of DOE-STD-1027-92, Hazard 24
Categorization and Accident Analysis Techniques for Compliance with DOE Order 5480.23, 25
Nuclear Safety Analysis Reports, are considered to contain significant quantities of radioactive 26
materials. Given that the 242-A Evaporator is categorized as a Hazard Category 2 Facility, 27
DOE-STD-3014-2006 is applicable. 28
29
DOE-STD-3014-2006 provides a methodology for conservatively estimating the total annual 30
frequency of an aircraft crash and indicates that if this total annual frequency is less than 10-6 per 31
year no further analysis is required. The total annual frequency consists of contributions from 32
general aviation aircraft, helicopters, commercial air carriers and air taxis, and from large and 33
small military aircraft. 34
35
The frequency of an aircraft crash at the 242-A Evaporator is evaluated in Appendix 3A. 36
Consistent with DOE-STD-3014-2006, aircraft crash frequencies for near-airport activities and 37
non-airport operations are evaluated. The total annual aircraft crash frequency for the 242-A 38
Evaporator is 4.42E-7/yr, and therefore no further analysis is required. 39
40
3.3.2.4.4.2 Vehicle Accident. A vehicle accident is a potential external initiator of fires and 41
local loss of power. The vehicles of interest for external event initiators are those being operated 42
that are not involved with internal 242-A Evaporator operations (e.g., trucks transporting 43
samples). (Note: A vehicle accident is not a potential external initiator of a waste leak because 44
of the robust design of the 242-A Building, which protects waste containing components 45
[e.g., piping].) 46
47
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The frequency of external event vehicle accidents is “anticipated” based on operational history. 1
The consequences of vehicle accidents are typically limited to the immediate vicinity of the 2
accident. Because of the robust nature of the 242-A Building, fires caused by vehicle accidents 3
are not expected to propagate to the interior of the building (e.g., evaporator and pump rooms) 4
where waste may be present. Fires from vehicle accidents may, however, affect the ventilation 5
system, parts of which are located outside the 242-A Building, and be an initiator of filtration 6
failures leading to unfiltered releases. The frequency of an external event vehicle accident that 7
affects the 242-A Evaporator (e.g., damaging high-efficiency particulate air [HEPA] filters and 8
causing filtration failures and unfiltered releases, causing loss of power) is judged to be 9
“unlikely.” 10
11
3.3.2.4.4.3 Range Fire. Range fires are external events that are one of the initiators of filtration 12
failures leading to unfiltered releases and power loss. As stated previously, because of the robust 13
nature of the 242-A Building, external fires are not expected to propagate to the interior of the 14
building (e.g., evaporator and pump room) where waste may be present. 15
16
Although range fires are often the result of human activities, range fires can also be the result of 17
natural phenomena (e.g., lightning strike). A vehicle accident is also a potential initiator of range 18
fires. On June 29, 2000, a vehicle accident started a range fire that spread across a significant 19
portion of the Hanford Site and resulted in a loss of power to several facilities. No frequency 20
differentiation is made regarding the cause of a range fire. Based on operating history, a range 21
fire is an “anticipated” event. 22
23
3.3.2.4.4.4 Loss of Site Power. Normal electrical power is provided to the Hanford Site by the 24
Bonneville Power Administration. The 230-kV power is reduced to 13.8 kV at the 251W 25
substation and distributed to the 200 East and 200 West areas. Loss of this site power is an 26
external event that could be an initiator of a flammable gas deflagration or detonation in the 27
C-A-1 vessel. Based on operating history, a loss of site power is an “anticipated” event. 28
29
3.3.2.4.4.5 Rail Accident. Rail accidents are postulated to occur both onsite and offsite. Onsite 30
rail accidents may initiate local loss of power and range fires. An offsite rail accident is 31
considered as a potential initiator of a range fire. 32
33
Onsite rail traffic is not currently associated with the 242-A Evaporator and therefore no 34
frequency is assigned to this external event. There are no commercial rail lines that traverse the 35
Hanford Site. Due to the distance between the 242-A Evaporator and the Hanford Site boundary, 36
an offsite rail accident is not postulated to initiate any events at the 242-A Evaporator. The 37
frequency of an offsite rail accident affecting the 242-A Evaporator is qualitatively estimated to 38
be “beyond extremely unlikely.” 39
40
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3.3.2.4.4.6 References. 1 2
DOE-STD-1027-92, 1997, Hazard Categorization and Accident Analysis Techniques for 3
Compliance with DOE Order 5480.23, Nuclear Safety Analysis Reports, Change Notice 4
No. 1, U.S. Department of Energy, Washington, D.C. 5
6
DOE-STD-3014-2006, 2006, Accident Analysis for Aircraft Crash into Hazardous Facilities, 7
U.S. Department of Energy, Washington, D.C. 8
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3.3.2.4.5 Natural Events. This section identifies and evaluates the natural events (i.e., natural 1 phenomena hazards) with the potential for initiating accidents at the 242-A Evaporator. Site 2 characteristics described in Chapter 1.0 and U.S. Department of Energy (DOE) requirements and 3 guidelines for the mitigation of natural phenomena hazards at DOE facilities1 support the natural 4 phenomena hazards analysis in this section. 5 6 3.3.2.4.5.1 Natural Phenomena Hazards. The hazard analysis of the 242-A Evaporator 7 includes natural events that are potential initiators of accidents (i.e., natural phenomena hazards). 8 Potential natural phenomena hazards identified include lightning, high winds, earthquakes 9 (seismic events), flooding, extreme temperatures, volcanic eruptions and ash fall, snow loads, 10 dust storms/dust devils, and hail storms. Representative accidents that have consequences 11 exceeding the guidelines for the onsite worker or that present significant facility worker hazards, 12 and that include natural events as possible initiators, are: 13 14
• Flammable gas accidents (Section 3.3.2.4.1) and 15 • Waste leaks and misroutes (Section 3.3.2.4.3). 16
17 The consequences of these representative accidents are provided in the referenced documented 18 safety analysis (DSA) sections. Therefore, only the frequencies of the natural events are 19 described here. (Note: There are additional representative accidents described in 20 Section 3.3.2.3.1 that may be initiated by natural events [e.g., filtration failures leading to 21 unfiltered releases, vessel failures]. However, these accidents do not have consequences 22 exceeding the guidelines for the onsite worker and do not present significant facility worker 23 hazards, and thus are not considered further.) 24 25 Lightning. Thunderstorms can produce lightning strikes that discharge the electrical potential 26 between the atmosphere and the ground. Although rare, ash fall and dust storms can also 27 produce lightning. Lightning is an initiator for a flammable gas accident in the C-A-1 vessel 28 (loss of power). The frequency and controls selected for a flammable gas accident in the C-A-1 29 vessel caused by a lightning strike are as follows. 30 31
Flammable gas accident in the C-A-1 vessel. The frequency of the initiating event (loss of 32 power) due to lightning is “anticipated.” The frequency of a flammable gas accident in the 33 C-A-1 vessel due to lightning is “anticipated.” The following safety-significant structure, 34 system, or component (SSC) credited to prevent a flammable gas accident in the C-A-1 35 vessel is designed to perform its safety function following a lightning strike (loss of power). 36
37 • C-A-1 vessel flammable gas control system (Section 4.4.1). 38
39
1 DOE Order 420.1C, Facility Safety and DOE-STD-1020-2016, Natural Phenomena Hazards Analysis and Design Criteria for DOE Facilities.
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High Winds. High winds near the 242-A Evaporator are postulated to cause a flammable gas 1 accident in the C-A-1 vessel (loss of power). The frequency and controls selected for a 2 flammable gas accident in the C-A-1 vessel caused by high winds are as follows. 3 4
Flammable gas accident in the C-A-1 vessel. The frequency of the initiating event (loss of 5 power) due to high winds is “anticipated.” The frequency of a flammable gas accident in the 6 C-A-1 vessel due to high winds is “anticipated.” The following safety-significant SSC 7 credited to prevent a flammable gas accident in the C-A-1 vessel is designed to perform its 8 safety function during and following high winds. 9
10 • C-A-1 vessel flammable gas control system (Section 4.4.1). 11
12 High winds at the 242-A Evaporator have not been identified as an initiator for waste leaks and 13 misroutes because the 242-A Building is designed to meet Performance Category (PC)-2 14 requirements.2 This assumption is protected by designating the 242-A Building as safety 15 significant (see Section 4.4.7). The safety function of the 242-A Building is to maintain 16 structural integrity for design basis wind loads. Maintaining structural integrity for design basis 17 wind loads prevents waste leaks and misroutes due to impacts from building (2 over 1) failure. 18 The functional requirement is to meet PC-2 for high winds. 19 20 Based on DOE requirements and guidelines, Chapter 1.0 references RPP-13033, Tank Farms 21 Documented Safety Analysis, for the design (evaluation) basis wind load and missile criteria at 22 the Hanford Site.3 23 24 Earthquakes. Accidents postulated to occur from an earthquake (seismic activity) include 25 flammable gas accidents and waste leaks and misroutes. Severe earthquakes are conservatively 26 assumed to cause: 27 28
• A loss of C-A-1 vessel vacuum and purge air flow with waste in the C-A-1 vessel 29 resulting in a flammable gas accident in the C-A-1 vessel. 30
31 • An overflow of waste from the C-A-1 vessel into process condensate tank TK-C-100 32
(e.g., loss of slurry out operation while continuing to feed waste to the C-A-1 vessel) 33 resulting in a flammable gas accident and a direct radiation hazard in process condensate 34 tank TK-C-100. 35
36 • A fine spray leak during a waste transfer using slurry pump P-B-2. 37
38 • A misroute of waste into the steam condensate weir box TK-C-103 (i.e., a waste leak in 39
an E-A-1 reboiler tube[s]/tube sheet) resulting in a direct radiation hazard in weir box 40 TK-C-103. 41
2 In accordance with DOE-STD-1021-93, Natural Phenomena Hazards Performance Categorization Guidelines for Structures, Systems, and Components, Performance Category (PC)-2 corresponds to the safety-significant designation of the 242-A Evaporator safety structures, systems, and components (SSC) (i.e., there are no 242-A Evaporator safety-class SSCs). 3 There is no design basis tornado for the Hanford Site.
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1 • A misroute of waste into the raw water system (i.e., a leak in a raw water line allowing 2
backflow of waste into the line) resulting in a chemical burn hazard (i.e., skin contact 3 with caustic waste) in uncontrolled areas. 4
5 Note: The following hazards may be present following a severe earthquake, but are addressed 6
as part of post-seismic event recovery actions because there is no immediate hazard to 7 facility workers. 8
9 − Flammable gas in the process condensate system (i.e., accumulation of flammable gas 10
generated by waste in process condensate piping or components) and chemical burn 11 hazards (i.e., skin contact with caustic waste) during process condensate sampling 12 activities resulting from boil-over or carry-over of waste from the C-A-1 vessel into 13 the process condensate system. 14
15 − Flammable gas in the steam condensate system (i.e., accumulation of flammable gas 16
generated by waste in the steam condensate piping or components) and chemical burn 17 hazards (i.e., skin contact with caustic waste) during steam condensate sampling 18 activities resulting from the misroute of waste into the steam condensate system (i.e., 19 a waste leak in an E-A-1 reboiler tube[s]/tube sheet). 20
21 − Flammable gas in the raw water system (i.e., accumulation of flammable gas 22
generated by waste in the raw water system piping or components) resulting from the 23 misroute of waste into the raw water system. 24
25 A severe earthquake that would be an initiator for the above accidents is assigned a frequency of 26 “unlikely” and is judged to result in the following information being reported to the Central Shift 27 Manager. 28 29
• Earth tremors, building movement, office furniture vibrations, etc., are reported to have 30 been observed by enough people to validate the likelihood of an earthquake. 31
32 • Personnel report injury or physical damage to facilities as a result of a perceived 33
earthquake. 34 35 The frequencies and controls selected for the events caused by an earthquake are as follows. 36 37
Flammable gas accident in the C-A-1 vessel. The frequency of a flammable gas accident 38 in the C-A-1 vessel due to an earthquake is “unlikely.” The following safety-significant SSC 39 is selected to address a flammable gas accident in the C-A-1 due to an earthquake. 40
41 • C-A-1 vessel seismic dump system (Section 4.4.3). 42
43
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The safety functions of the C-A-1 vessel seismic dump system include: 1 2
1. To drain the C-A-1 vessel via the feed line, and 3 2. To limit the temperature of the residual waste left in the C-A-1 vessel. 4
5 Draining the C-A-1 vessel via the feed line following a seismic event prevents a flammable 6 gas accident in the C-A-1 vessel if the temperature of the residual waste left in the C-A-1 7 vessel is limited by stopping steam to the E-A-1 reboiler and stopping recirculation pump 8 P-B-1. The functional requirements of the C-A-1 vessel seismic dump system include, upon 9 detection of a seismic event that could cause loss of C-A-1 vessel vacuum and purge air flow, 10 to (1) open feed valve HV-CA1-1 and stop feed pump 241-AW-P-102-1 to drain the C-A-1 11 vessel, and (2) close steam isolation valve HV-EA1-5 and stop recirculation pump P-B-1 to 12 stop heat sources to the residual waste left in the C-A-1 vessel. (Note: The C-A-1 vessel 13 seismic dump system is not required to drain the vessel during the seismic event, but rather 14 following the event.) 15
16 Flammable gas accident and direct radiation hazard in process condensate tank 17 TK-C-100. The frequency of a flammable gas accident or a direct radiation hazard in 18 process condensate tank TK-C-100 due to an earthquake is “extremely unlikely.” The 19 following safety-significant SSC is selected to address a flammable gas accident and a direct 20 radiation hazard in process condensate tank TK-C-100 due to an earthquake. 21
22 • C-A-1 vessel seismic dump system (Section 4.4.3). 23
24 The safety functions of the C-A-1 vessel seismic dump system include preventing the 25 overflow of waste from the C-A-1 vessel into the process condensate system. Preventing the 26 overflow of waste from the C-A-1 vessel into the process condensate system prevents a 27 flammable gas accident and a direct radiation hazard in process condensate tank TK-C-100. 28 The functional requirements of the C-A-1 vessel seismic dump system include, upon 29 detection of a seismic event that could cause the overflow of waste from the C-A-1 vessel 30 into process condensate tank TK-C-100, to stop feed pump 241-AW-P-102-1 and open feed 31 valve HV-CA1-1 to drain the C-A-1 vessel. (Note: The C-A-1 vessel seismic dump system 32 is not required to drain the vessel during the seismic event, but rather following the event.) 33
34 Fine spray leak during a waste transfer using slurry pump P-B-2. The frequency of a 35 severe earthquake causing a fine spray leak is “extremely unlikely” because the accident 36 consequence requires a specific crack geometry that produces near optimal aerosol 37 generation. Most cracks are expected to have a width such that they would not be optimal 38 producers of fine aerosol spray. The following TSR Key Element is selected to address this 39 scenario. 40
43 The safety function of the AC Key Element Emergency Preparedness is to establish 44 emergency preparedness requirements to reduce the risk from a fine spray leak caused by 45 waste slurry transfer piping failure during a waste transfer using slurry pump P-B-2 initiated 46
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by a seismic event (shutting down slurry pump P-B-2). The functional requirement is to shut 1 down slurry pump P-B-2 following seismic events that could cause waste slurry transfer 2 piping failure (i.e., a waste leak). 3
4 Misroute into the Steam Condensate Weir Box TK-C-103 (direct radiation hazard in 5 TK-C-103). The frequency of a severe earthquake causing a facility worker direct radiation 6 hazard is “unlikely.” The following TSR key Element is selected to address this scenario. 7
10 The safety function of the AC Key Element Emergency Preparedness is to establish 11 emergency preparedness requirements to reduce the risk from a waste misroute into the 12 steam condensate weir box TK-C-103 caused by E-A-1 reboiler tube/tube sheet failure 13 initiated by a seismic event (evacuate personnel from the condenser room). The functional 14 requirement is to evacuate personnel from the condenser room following seismic events that 15 could cause E-A-1 reboiler tube/tube sheet failure (i.e., waste misroute into the steam 16 condensate system). 17
18 Misroute into the Raw Water System in Non-Radiologically Controlled Areas (chemical 19 burn hazard). The frequency of a severe earthquake causing a facility worker chemical 20 burn hazard is ‘extremely unlikely.” The following TSR Key Element is selected to address 21 this scenario. 22 23
The safety function of the AC Key Element Emergency Preparedness is to establish 26 emergency preparedness requirements to reduce the risk from a misroute into the raw water 27 system in non-radiologically controlled areas caused by backflow preventer device 28 PSV-RW-3 or BFP-RW-11 failure initiated by a seismic event (evacuate untrained personnel 29 from areas that are not radiologically controlled). (Note: The pump room, evaporator room, 30 condenser room, and load-out and hot-equipment storage room are radiologically controlled 31 areas.) The functional requirement is to evacuate untrained personnel from the areas that are 32 not radiologically controlled following seismic events that could cause backflow prevention 33 device PSV-RW-3 or BFP-RW-11 failure (i.e., waste misroute into the raw water system in 34 uncontrolled areas). 35
36 For the 242-A Evaporator, PC-2 is used as the design (evaluation) basis earthquake. The 37 earthquake load design for PC-2 is to follow International Building Code (IBC 2009) for 38 Occupancy Category IV requirements with an importance factor = 1.5 (Chapter 1.0). 39 40 Flooding. Natural flooding is not a credible hazard for the 242-A Evaporator. As described in 41 Chapter 1.0, the 242-A Evaporator elevation is above the flood level of the Columbia River 42 based on U.S. Army Corps of Engineering evaluations of postulated failures of the Grand Coulee 43 Dam. For the postulated maximum probable flood of Cold Creek, no surface flooding at the 44 242-A Evaporator is anticipated. Because of the expected short duration of precipitation-caused 45 (flash) floods, a significant rise in the water table is not expected and, therefore, the 242-A 46
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Evaporator would not be affected. Local flooding from probable maximum precipitation storms 1 is also insufficient to affect the 242-A Evaporator. 2 3 Note: Flooding at the 242-A Evaporator by system failures (e.g., water line breaks) is identified 4
and addressed in the hazard analysis. 5 6 Extreme Temperatures. High and low temperature extremes at the 242-A Evaporator are 7 described in Chapter 1.0. Extreme temperatures at the 242-A Evaporator have not been 8 identified as an initiator for flammable gas accidents or waste leaks and misroutes. The 242-A 9 Evaporator will be shut down well before the internal building temperature reaches the freezing 10 point. Operators monitor rooms in the facility regularly, and will be aware of the loss of heat. 11 The design of safety-significant SSCs considers process and environmental temperatures 12 (including consideration of extreme high outdoor air temperatures). TFC-ENG-STD-02, 13 Environmental/Seasonal Requirements for TOC Systems, Structures, and Components, 14 establishes the extreme outdoor air temperature design basis for Tank Operations Contractor 15 (TOC) facilities (i.e., -25°F to 115°F). 16 17 Volcanic Eruption and Ash Fall. Volcanic eruption (i.e., flow of molten lava) is a beyond 18 design basis event at the Hanford site. Ash fall near the 242-A Evaporator is postulated to cause 19 a flammable gas accident in the C-A-1 vessel (loss of C-A-1 vessel vacuum and purge air flow 20 with waste in the C-A-1 vessel) due (1) to a loss of steam from the package boiler facility due to 21 ash fall (loads or exposure); (2) loss of power; and/or (3) ash ingestion into the 242-A Building 22 and 242-AB Building that results in failures in the monitoring and control system (MCS). The 23 frequency of a flammable gas accident in the C-A-1 vessel due to ash fall is “unlikely.” The 24 following safety-significant SSC credited to prevent a flammable gas accident in the C-A-1 25 vessel is designed to perform its safety function during and following an ash fall event (loads and 26 exposure). 27 28
• C-A-1 vessel flammable gas control system (Section 4.4.1). 29 30 Ash fall loading at the 242-A Evaporator is not identified as an initiator for flammable gas 31 accidents or waste leaks and misroutes because the 242-A Building is designed to meet PC-2 32 requirements. This assumption is protected by designating the 242-A Building as safety 33 significant (see Section 4.4.7). The safety function of the 242-A Building is to maintain 34 structural integrity for design basis ash fall loads. Maintaining structural integrity for design 35 basis ash fall loads prevents flammable gas accidents or waste leaks and misroutes due to 36 impacts from building (2 over 1) failure. The functional requirement is to meet PC-2 for ash fall 37 loads. 38 39 TFC-ENG-STD-06, Design Loads for Tank Farm Facilities, establishes the ash loading design 40 basis for TOC facilities (i.e., 11.8 lb/ft2). 41 42 Snow Loads. Snow loading at the 242-A Evaporator is not identified as an initiator for 43 flammable gas accidents or waste leaks and misroutes because the 242-A Building is designed to 44 meet PC-2 requirements. This assumption is protected by designating the 242-A Building as 45 safety significant (see Section 4.4.7). The safety function of the 242-A Building is to maintain 46
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structural integrity for design basis snow loads. Maintaining structural integrity for design basis 1 snow loads prevents flammable gas accidents or waste leaks and misroutes due to impacts from 2 building (2 over 1) failure. The functional requirement is to meet PC-2 for snow loads. 3 4 TFC-ENG-STD-06 establishes the ground snow loading design basis for TOC facilities 5 (i.e., 15 lb/ft2) and specifies that unbalanced snow loads resulting from drifting or sliding be 6 considered. 7 8 Dust Storms/Dust Devils. Dust storms and blowing dust is an “anticipated” occurrence at the 9 242-A Evaporator (see Chapter 1.0). Dust storms near the 242-A Evaporator are postulated to 10 cause a flammable gas accident in the C-A-1 vessel (loss of C-A-1 vessel vacuum and purge air 11 flow with waste in the C-A-1 vessel) due (1) to a loss of steam from the package boiler facility 12 due to dust storms; (2) loss of power, and/or (3) dust ingestion into the 242-A Building and 13 242-AB Building that results in failures in the monitoring and control system (MCS). The 14 frequency of a flammable gas accident in the C-A-1 vessel due to dust storms and blowing dust 15 is “unlikely.” The following safety-significant SSC credited to prevent a flammable gas accident 16 in the C-A-1 vessel is designed to perform its safety function during and following a dust storm. 17 18
• C-A-1 vessel flammable gas control system (Section 4.4.1). 19 20 Hail Storm. In addition to lightning, thunderstorms can produce hail. Hail storms at the 21 evaporator have not been identified as an initiator for flammable gas accidents or waste leaks and 22 misroutes. 23 24 3.3.2.4.5.2 Natural Events Risk. Because natural events are simply a specific cause for an 25 accident, the consequences for accidents initiated by natural events are the same as discussed for 26 the representative accidents and their associated hazardous conditions in the preceding DSA 27 sections. The only unique aspect of natural events is the potential of natural events 28 (e.g., earthquakes) to cause multiple failures (i.e., common cause failures). 29 30 Although a natural event (e.g., design basis earthquake) may cause multiple accidents 31 (e.g., flammable gas accidents, waste leaks and misroutes), it is not reasonable to expect that all 32 of the releases would occur in the same time frame or be the highest estimated release for the 33 individual accidents. That is, a waste leak would occur at the time of the event or shortly 34 thereafter, where as a flammable gas accident would occur days to weeks later because of the 35 time required for flammable gases to accumulate to the lower-flammability limit (LFL). For the 36 initiated accidents there would be a range of consequences below the reasonably conservative 37 consequences estimated for each individual accident. For this reason, it is judged that, even if 38 natural events initiated multiple accidents, any cumulative effects would not increase the 39 consequence level for the maximum offsite individual (MOI) (toxicological) or the onsite worker 40 (100 m) (radiological and toxicological) above those estimated for the representative accidents 41 and, therefore, no additional controls (safety SSCs or TSRs) are required beyond those already 42 identified for the representative accidents. 43 44
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3.3.2.4.5.3 Summary of Safety-Significant Structures, Systems, and Components; 1 Technical Safety Requirements; and Defense-in-Depth. Safety-significant SSCs and TSRs 2 selected specifically to address hazards and accidents associated with natural events are listed in 3 Tables 3.3.2.4.5-1, “Safety-Significant Structures, Systems, and Components for Natural 4 Events,” and 3.3.2.4.5-2, “Summary of Technical Safety Requirements for Natural Events,” 5 respectively and described above. 6 7 No defense-in depth features have been selected for natural events. 8 9 3.3.2.4.5.4 References. 10 11 DOE O 420.1C, Chg 1, 2015, Facility Safety, U.S. Department of Energy, Washington, D.C. 12 13 DOE-STD-1020-2016, 2016, Natural Phenomena Hazards Analysis and Design Criteria for 14
DOE Facilities, U.S. Department of Energy, Washington, D.C. 15 16 DOE-STD-1021-93, 2002, Natural Phenomena Hazards Performance Categorization Guidelines 17
for Structures, Systems, and Components, U.S. Department of Energy, Washington, D.C. 18 19 HNF-15279, 242-A Evaporator Technical Safety Requirements, as amended, Washington River 20
Protection Solutions LLC, Richland, Washington. 21 22 IBC, 2009, International Building Code, International Code Council, Inc., Country Club Hills, 23
Illinois. 24 25 RPP-13033, Tank Farms Documented Safety Analysis, as amended, Washington River Protection 26
Solutions LLC, Richland, Washington. 27 28 TFC-ENG-STD-02, Environmental/Seasonal Requirements for TOC Systems, Structures, and 29
Components, as amended, Washington River Protection Solutions LLC, Richland, 30 Washington. 31
32 TFC-ENG-STD-06, Design Loads for Tank Farm Facilities, as amended, Washington River 33
Table 3.3.2.4.5-1. Safety-Significant Structures, Systems, and Components for Natural Events.
Structures, systems, and components
Safety classification Safety function Comments
C-A-1 vessel seismic dump system
Safety-significant 1. To drain the C-A-1 vessel via the feed line,
2. To limit the temperature
of the residual waste left in the C-A-1 vessel, and
3. To prevent the overflow
of waste from the C-A-1 vessel into the process condensate system.
Draining the C-A-1 vessel via the feed line following a seismic event prevents a flammable gas accident in the C-A-1 vessel if the temperature of the residual waste left in the C-A-1 vessel is limited by stopping steam to the E-A-1 reboiler and stopping recirculation pump P-B-1. Preventing the overflow of waste from the C-A-1 vessel into the process condensate system prevents a flammable gas accident and a direct radiation hazard in process condensate tank TK-C-100.
The functional requirements are to, upon detection of a seismic event that could cause loss of C-A-1 vessel vacuum and purge air flow, or overflow of waste from the C-A-1 vessel into process condensate tank TK-C-100, (1) open feed valve HV-CA1-1 and stop feed pump 241-AW-P-102-1 to drain the C-A-1 vessel, and (2) close steam isolation valve HV-EA1-5 and stop recirculation pump P-B-1 to stop heat sources to the residual waste left in the C-A-1 vessel. (Note: The C-A-1 vessel seismic dump system is not required to drain the vessel during the seismic event, but rather following the event.)
242-A Building Safety-significant To maintain structural integrity for design basis wind loads, snow loads, and ash fall loads. Maintaining structural integrity for design basis wind loads, snow loads, and ash fall loads prevents flammable gas accidents or waste leaks and misroutes due to impacts from building (2 over 1) failure.
The functional requirement is to meet PC-2 for high winds, snow, and ash fall.
Notes:
PC = Performance Category
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Table 3.3.2.4.5-2. Summary of Technical Safety Requirements for Natural Events.
Technical safety requirement* Safety function Comments KE: Emergency preparedness To establish emergency
preparedness requirements to reduce the risk from the following accidents potentially initiated by a seismic event. • Fine spray leak caused by waste
slurry transfer piping failure during a waste transfer using slurry pump P-B-2.
• Waste misroute into the steam condensate weir box TK-C-103 (direct radiation hazard) caused by E-A-1 reboiler tube/tube sheet failure.
• Waste misroute into the raw water system in uncontrolled areas (chemical burn hazard) caused by backflow prevention device PSV-RW-3 or BFP-RW-11 failure.
The functional requirements are to: • Shut down slurry pump
P-B-2 following seismic events that could cause waste slurry transfer piping failure (i.e., a waste leak).
• Evacuate personnel from the
condenser room following seismic events that could cause E-A-1 reboiler tube/tube sheet failure (i.e., waste misroute into the steam condensate system).
• Evacuate untrained personnel from areas that are not radiologically controlled following seismic events that could cause backflow prevention device PSV-RW-3 or BFP-RW-11 failure (i.e., waste misroute into the raw water system in uncontrolled areas).
Notes: *For the complete text of the controls summarized in this table refer to the latest revision of HNF-15279
HNF-15279, 242-A Evaporator Technical Safety Requirements, as amended, Washington River Protection
Solutions LLC, Richland, Washington.
AC = administrative control. KE = key element.
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3.4 ACCIDENT ANALYSIS 1 2
This section describes the quantitative accident analysis and is comprised of three discrete 3
subsections. Section 3.4.1 describes the methodology for estimating radiological and 4
toxicological consequences. Radionuclide and chemical inventories, exposure pathways, and 5
radiological dose and chemical exposure calculation methods are discussed in this section. 6
Section 3.4.2 describes the selection criteria for the design basis accidents and documents the 7
radiological consequence analysis that was conducted for each accident. A quantitative analysis 8
of the unmitigated offsite radiological consequences for each design basis accident is presented 9
and the results are compared with the Evaluation Guideline of 25 rem. Section 3.4.3 describes 10
the assessment of accidents, which may be beyond the design basis of the facility. An 11
assessment of the need to analyze beyond design basis accident to provide a perspective of the 12
residual risk associated with the operation of the facility also is provided in this section. 13
14
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3.4.1 Methodology 1 2 This section summarizes the general calculation methods used to quantify the radiological and 3 toxicological consequences of postulated accidents. Consequence calculation methods specific 4 to individual postulated accidents are summarized in the individual analyses presented in 5 Sections 3.3.2.4 and 3.4.2. In this section, and Sections 3.3.2.4 and 3.4.2, reference is made to 6 computer programs used in support of the analyses. A summary description of these computer 7 programs is presented in the appropriate supporting documents. 8 9 The development of the radiological source term and unit-liter dose (ULD) is explained in 10 RPP-5924, Radiological Source Terms for Tank Farms Safety Analysis. The development of the 11 toxicological or chemical source terms and sum of fractions (SOF) are explained in RPP-30604, 12 Tank Farms Safety Analyses Chemical Source Term Methodology. 13 14 Atmospheric dispersion and the methods for calculating radiological and toxicological 15 consequences are given in RPP-13482, Atmospheric Dispersion Coefficients and Radiological 16 and Toxicological Exposure Methodology for Use in Tank Farms. The radiological and 17 toxicological consequences of accidents are calculated at the location of the maximum onsite and 18 offsite individual. The maximum onsite and offsite individuals are defined as follows. 19 20
• Maximum Onsite Individual. The hypothetical onsite receptor located at or beyond 100 21 m (minimum) from the point of release at which the maximum dose occurs. This 22 receptor represents the onsite worker for the purpose of reporting the consequences of 23 postulated accidents. 24
25 • Maximum Offsite Individual. The hypothetical receptor located at or beyond the 26
Hanford Site boundary location at the distance from the point of release at which the 27 maximum dose occurs. This receptor represents the maximally-exposed offsite 28 individual (MOI) for the purpose of reporting the consequences of postulated accidents. 29
30 For 242-A Evaporator accidents, the maximum onsite individual is located at 100 m when 31 radioactive or hazardous material is released at ground level. For elevated releases from 32 ventilation system stacks, the maximum onsite individual may be located beyond 100 m from the 33 release point. 34 35 The distances from the 200 Areas (i.e., tank farms, which include the 242-A Evaporator) to the 36 Hanford Site boundary are shown in Table 3.4.1-1. Atmospheric dispersion coefficients for 37 releases in the 200 Areas that are also used for the 242-A Evaporator are developed in detail in 38 RPP-13482 for the onsite (worker) and offsite (MOI) receptors. The basic atmospheric 39 dispersion coefficients (χ/Q') for acute releases are 95th percentile values over all directions from 40 the point of release, either at a specified distance or around the site boundary. A number of 41 modifications may be made to the dispersion model depending on specific details of the release. 42 RPP-13482 contains detailed discussions of the methodologies used to estimate atmospheric 43 dispersion effects for various cases used for 242-A Evaporator hazard and accident analyses. 44 Specifically, acute (1-hr) χ/Q' were calculated assuming mixing of the release plume with the 45 building wake. 46 47
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Under normal circumstances, public access is provided through the Hanford Site on Washington 1 State Highways 240, 24, and 243. Because U.S. Department of Energy (DOE) controls the land 2 on either side of State Highway 240, public usage is considered to be transient (Scott 1995, 3 “Clarification of Hanford Site Boundaries for Current and Future Use in Safety Analyses”). 4 5 3.4.1.1 Radiological Consequence Calculation Methodology. The ULD is the inhalation 6 dose obtained if an individual inhales 1 L of waste. The ULDs provide a practical way to 7 calculate radiological dose consequences for a variety of potential accidents. The safety analysis 8 relies on consequence analysis to calculate the radiation dose to defined receptors onsite and 9 offsite. These analyses need a ‘source term’ to calculate the dose. The source term is a quantity 10 of specified hazardous material. The material specification must include quantity, physical form, 11 and specific properties of the hazardous material. For radiation hazards, this includes specifying 12 the particle sizes, the quantity in mass per volume of air, the radioactive isotopes present, and the 13 concentrations of the isotopes. The ULD provides the information for radioactive isotopes 14 present and their concentrations in 1 L of waste, and quantifies this information as radiological 15 dose in Sieverts per liter of waste. 16 17 The dose conversion factors (DCF) used to calculate the ULDs used in this documented safety 18 analysis (DSA) are taken from the following: 19 20
• ICRP-68, Dose Coefficients for Intakes of Radionuclides by Workers—Replacement of 21 ICRP Publication 61; 22
23 • ICRP-71, Age Dependent Doses to Members of the Public from Intake of Radionuclides 24
Part 4 Inhalation Dose Coefficients; and 25 26
• ICRP-72, Age Dependent Doses to Members of the Public from Intake of Radionuclides 27 Part 5 Compilation of Ingestion and Inhalation Dose Coefficients. 28
29 The inhalation ULDs calculated using ICRP-68 DCFs are used for calculating doses to the 30 maximum onsite individual. The DCFs in ICRP-68 are given for up to three absorption types for 31 each isotope. ICRP-68 uses the notation of F, M, and S (fast, moderate, and slow) for absorption 32 type. The absorption type depends on the chemical compound of the isotope and how the human 33 body processes the compound. The absorption type that produces the largest dose is used to 34 calculate onsite ULDs, except for 90Sr and 3H. The F absorption type is used for 90Sr rather than 35 the larger S absorption type because there is a paucity of Type S 90Sr compounds in the waste. 36 The DCF for tritiated water is used for 3H. 37 38 The ICRP-68 inhalation DCFs are given for both a 1-μm and 5-μm activity median aerodynamic 39 diameter (AMAD) particle size. ICRP-68 states in Section 2.1: “For occupational exposure the 40 default value now recommended for the AMAD is 5 μm (ICRP-68, Paragraph 181), which is 41 considered to be more representative of workplace aerosols than the 1 μm value adopted in ICRP 42 Publication 30.” DOE-HDBK-3010-94, Airborne Release Fractions/Rates and Respirable 43 Fractions for Nonreactor Nuclear Facilities, considers particles less than 10 μm in diameter as 44 respirable. The use of the 5-μm DCFs, therefore, is reasonable and conservative for occupational 45 exposure. 46 47
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The inhalation ULDs calculated using DCFs from ICRP-71 and ICRP-72 are used for calculating 1 doses to the MOI. ICRP-71 and ICRP-72 give age-dependent DCFs for members of the public. 2 ICRP-71 discusses the methods and recommendations on absorption types and ICRP-72 gives a 3 compiled summary of the DCFs. Thus, the nomenclature of ICRP-71/72 is used here to refer to 4 the compiled list of DCFs in ICRP-72 that are based on the methods of ICRP-71. 5 6 DCFs in ICRP-71/72 are given for different ages: 3 mo, 1 yr, 5 yr, 10 yr, 15 yr, and adult. In 7 general, DCFs for infants are about a factor of two higher than for adults, and intermediate ages 8 show intermediate DCFs. The data in ICRP-71 indicate that the breathing rate in cubic meters 9 per second is lower for the younger ages. Dose is a function of both DCF and breathing rate. 10 The product of breathing rate and DCF is highest for the adult for the dominant isotopes. 11 Therefore, using the adult factors is conservative. 12 13 DCFs are given only for 1-μm AMAD in ICRP-71/72 (i.e., no 5-μm data are given). ICRP-71 14 indicates in Section 2.3: “For environmental exposure, the default AMAD is taken to be 1 μm.” 15 16 ICRP-72 gives data for three absorption types (F, M, and S) for many of the isotopes. ICRP-71 17 provides recommendations regarding absorption type for a number of the isotopes. Most often 18 the recommended absorption type is type M. The recommended absorption type from ICRP-71 19 is used or, if no recommendation is provided for an isotope, then the type M data is used. 20 Exceptions to using the recommended absorption type, and those not using M type, are as 21 follows. 22 23
• The F absorption type is recommended for selenium; however, the more conservative 24 M type data is used. 25
26 • The F absorption type is recommended for iodine. 27
28 • The F absorption type is recommended for cesium. 29
30 • The S absorption type is recommended for thorium; however, the more conservative 31
M type data is used. 32 33 3.4.1.1.1 Radionuclide Inventory. The Tank Waste Characterization Program has taken many 34 core samples, grab samples, and auger samples from the single-shell tanks (SST) and 35 double-shell tanks (DST). In conjunction with this sampling effort, analysis of the data has been 36 performed, including modeling of the sampling data and the effect of radionuclide decay on the 37 compositions. The Best-Basis Inventory (BBI) contains the Tank Operations 38 Contractor-approved data for tank contents. The BBI contains inventory information for 39 46 radionuclides (listed in Table 3.4.1-2) for waste layers in DSTs and SSTs. 40 41 The waste processed through the 242-A Evaporator is represented by the worst case wastes 42 stored in DSTs, as reported in the BBI. This is reasonably conservative given that the wastes 43 stored in DSTs include those that have been processed through the 242-A Evaporator and 44 concentrated to higher levels than planned for future 242-A Evaporator operations. Although it 45
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is called slurry, the resulting 242-A Evaporator processed waste is not expected to contain 1 significant amounts of entrained solids. The base case assumption for hazard analysis is, 2 therefore, 0 vol% solids. However, a solids content of up to 1 vol% is evaluated as a sensitivity 3 case for hazard analysis and as a bounding case for offsite radiological consequence calculations. 4 5 The waste to be transferred to and returned from the 242-A Evaporator is evaluated in a waste 6 compatibility assessment (based on sample data) and compared to the hazard and accident 7 analysis assumptions (see Section 5.5.3.4). The hazard and accident analysis assumptions are 8 required to be updated when necessary to bound the waste to be transferred to and returned from 9 the 242-A Evaporator. 10 11 3.4.1.1.2 Exposure Pathways. The radiological consequence calculations use the exposure 12 pathways recommended in DOE-STD-3009-94, Preparation Guide for U.S. Department of 13 Energy Nonreactor Nuclear Facility Documented Safety Analyses, Appendix A, “Evaluation 14 Guideline.” Two potential radiological exposure pathways (internal and external) are associated 15 with releases of radioactive materials. The total effective dose (TED) calculated for an 16 individual is equal to the sum of the dose contributions from these two exposure pathways. 17 18 Internal Exposure Pathway. The internal exposure pathway used in the DSA is inhalation. 19 Exposure by way of the inhalation pathway occurs (1) when an accident results in a release of 20 airborne radioactive material that is transported downwind and inhaled by the maximum onsite 21 and offsite individuals or (2) when radioactive materials that have been deposited on the ground 22 become suspended and are subsequently inhaled. The resuspension dose is not included in the 23 consequence calculations because inhalation of resuspended material is generally orders of 24 magnitude less than that from inhalation of the material in the plume. 25 26 External Exposure Pathway. External exposure pathways include ground shine and direct 27 shine from a concentrated radioactive source, such as a pool formed from a spill of liquid 28 radioactive material. 29 30 Ground shine is not included in the consequence calculations because ground shine is a 31 slow-to-develop dose pathway, which produces relatively low dose rates, and is not an 32 immediate threat to personnel. Ground shine will be mitigated by either evacuation and posting 33 of contaminated areas or decontamination of the areas. 34 35 Direct shine from pools formed from liquid leaks may be included in the accident evaluations, 36 but not included in the ULDs because this dose varies depending on the accident scenario. The 37 calculation documents specific to leak or spill scenarios should be consulted for details of the 38 pool shine calculations that may be included in the dose consequences. 39 40 3.4.1.1.3 Dose Calculation Methods. The dose calculation methods are described in 41 RPP-13482. For accident analyses without controls, dose calculations for the maximum onsite 42 individual assume that the individual remains at a distance of 100 m (or at the distance of 43 maximum dose if greater than 100 m) for the duration of plume passage. The durations for 44 plume passage are determined in the individual accident analyses. For accident analyses with 45 controls, exposure durations may be based on a demonstrated ability to detect the accident and 46 protect the receptor. 47
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1 The first step in calculating the dose is to derive the airborne source term (i.e., the amount of 2 airborne radioactive material generated by the accident that is available for transport to the 3 maximum onsite and offsite individuals). As presented in DOE-HDBK-3010-94, the airborne 4 source term is typically estimated as is shown in Equation 3.4.1-1: 5 6 Source term = MAR x DR x ARF (or ARR x T) x RF x LPF (3.4.1-1) 7 8 where: 9 10 MAR = material at risk 11 DR = damage ratio 12 ARF = airborne release fraction 13 ARR = airborne release rate (for continuous releases) 14 T = time 15 RF = respirable fraction 16 LPF = leak path factor. 17 18 The material at risk (MAR) is the amount of material available to be acted on by 19 accident-induced physical stresses such as temperature or pressure. 20 21 The damage ratio (DR) is the fraction of the MAR actually impacted by the accident-generated 22 conditions. There is interdependence in the definitions of MAR and DR. Material determined 23 not to be affected by the accident forces could be excluded from the MAR, or it could be 24 included and accounted for using the DR. 25 26 The airborne release fraction (ARF) is the coefficient used to estimate the amount of material 27 suspended in air as an aerosol and thus available for transport caused by the physical stresses of a 28 specific accident. For mechanisms that continuously act to suspend material (e.g., a spray 29 release), an airborne release rate (ARR) is required to estimate the potential airborne release 30 from postulated accident conditions. 31 32 The respirable fraction (RF) is the fraction of airborne particles that can be transported through 33 air and inhaled into the pulmonary region of the human respiratory system, and includes particles 34 having a 10-μm aerodynamic equivalent diameter or less (DOE-HDBK-3010-94). The 35 aerodynamic equivalent diameter is the diameter of a sphere of unit density (1 g/cm3) that 36 exhibits the same terminal velocity as the particle in question. 37 38 The leak path factor (LPF) is the fraction of the material in the aerosol transported through a 39 confinement deposition or filtration mechanism. The LPFs are developed as applicable based on 40 (1) established relationships among the size of the particulate material, airborne transport 41 mechanisms, and losses by deposition; or (2) specified filtration efficiencies 42 (DOE-HDBK-3010-94). 43 44 Appropriately conservative values for MAR, DR, ARF/ARR, RF, and LPF are selected based on 45 the best available information. In some cases, facility-specific data allows for selection of a 46 relatively precise value. In the absence of specific data, values must be selected from the 47
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available literature. In such cases, potentially relevant reports are researched and values selected 1 that closely match the subject accident scenario in terms of (1) design, (2) physical and chemical 2 properties of the MAR, and (3) magnitude and type of energy released. 3 4 Given an airborne source term, the dose from the inhalation pathway is calculated as shown in 5 Equation 3.4.1-2. 6 7 Inhalation: 8 9
=
LSvULDx
smRx
msx)L(Q)Sv(D inh
3
3inh Q'χ (3.4.1-2) 10
11 where: 12 13 Dinh = dose resulting from inhalation 14 Q = respirable source term 15 χ/Q' = atmospheric dispersion coefficient 16 R = breathing rate 17 ULDinh = inhalation unit liter dose. 18 19 For the inhalation pathway, the dose calculated is the 50-yr committed effective dose. The 20 committed effective dose is defined as the dose received by the individual during the 50 yrs. 21 following the uptake. For the maximum onsite individual, the committed effective dose must be 22 combined with the deep dose from external exposure (if any) to yield the total effective dose. 23 24 The χ/Q' represents the dilution of an airborne contaminant caused by atmospheric turbulence 25 resulting from wind speed and atmospheric stability conditions. The χ/Q' values applicable to 26 200 Area facilities (e.g., tank farms) that are used for 242-A Evaporator accident analysis have 27 been calculated and are documented in RPP-13482. The χ/Q' values applicable to ground-level 28 releases are shown in Tables 3.4.1-3 and 3.4.1-4. The values shown are the 95th percentile 29 overall (all direction sectors) χ/Q's as defined by the U.S. Nuclear Regulatory Commission 30 (NRC) Regulatory Guide 1.145, “Atmospheric Dispersion Models for Potential Accident 31 Consequence Assessments at Nuclear Power Plants.” Tables 3.4.1-3 and 3.4.1-4 also present the 32 maximum 50th percentile χ/Q' values. These values are provided to quantify the relative 33 conservatism associated with use of bounding χ/Q' values. 34 35 The bounding integrated χ/Q' values shown in Table 3.4.1-3 are used for release durations up to 36 1 hr. The integrated χ/Q' with plume meander are used for release durations of between 37 1 and 2 hrs. Plume meander accounts for enhanced horizontal spreading of the plume due to 38 random changes in wind direction during light wind and relatively stable atmospheric conditions. 39 Plume meander corrections were made according to the empirical model given in NRC 1.145. 40 As recommended in NRC 1.145, for release durations greater than 2 hrs., a logarithmic 41 interpolation is made between the acute bounding χ/Q' with plume meander and the chronic 42 annual average χ/Q' values (listed in Table 3.4.1-3 and 3.4.1-4). The interpolation for 8 hrs. has 43 been performed and is included in the table. 44 45
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Breathing rate values used to calculate the radiological consequences of accidents are taken from 1 ICRP 68 (footnote to Table 1) for the onsite receptor and ICRP 71 (footnote to Table 6) for the 2 MOI. For the maximum onsite individual, exposures with durations less than 24 hrs or 3 exposures to releases with highly variable rates, the light activity breathing rate is used 4 (i.e., 3.33 x 10-4 m3/s). For the MOI exposed for at least 24 hrs. to a relatively constant-rate 5 release, the 24-hr average breathing rate is used (i.e., 2.57 x 10-4 m3/s). For shorter duration 6 releases the light activity breathing rate is used. 7 8 3.4.1.2 Toxicological Consequence Calculation Methodology. The waste processed through 9 the 242-A Evaporator is represented by the worst case wastes stored in DSTs, as reported in the 10 BBI. This is reasonably conservative given that the wastes stored in DSTs include those that 11 have been processed through the 242-A Evaporator and concentrated to higher levels than 12 planned for future 242-A Evaporator operations. Although it is called slurry, the resulting 242-A 13 Evaporator processed waste is not expected to contain significant amounts of entrained solids. 14 The base case assumption for the hazard analysis is, therefore, 0 vol% solids. However, a solids 15 content of up to 1 vol% is evaluated as a sensitivity case for hazard analysis. 16 17 The toxicological source terms developed by the application of the RPP-30604 methodology are 18 based on the waste as it is thought to exist in the tanks, and do not include potential 19 accident-specific effects (e.g., chemical changes associated with a deflagration accident, 20 neutralization of caustic by reaction with atmospheric carbon dioxide). 21 22 3.4.1.2.1 Chemical Inventory. Toxic chemical source terms for the high-level radioactive 23 wastes were developed using data from the BBI and either published toxic chemical exposure 24 guidelines or toxicological guidelines based on a published methodology. Because the BBI does 25 not provide specific chemical compounds, BBI information must be processed before it can be 26 used for the toxicological evaluation. The complete methodology for development of the 27 chemical source terms is given in RPP-30604. The methodology described in RPP-30604 uses a 28 set of non-tank specific chemical equations to determine the appropriate chemical compounds 29 present in the waste layers. The chemical equations were derived from thermodynamic 30 modeling, and consider the predominant waste chemistry. Individual compound toxicities were 31 also considered in the development of the chemical equations to ensure reasonably conservative 32 toxicological source terms. 33 34 Toxicological risk guidelines (i.e., allowable human exposure limits) are identified for each 35 chemical compound. The toxicological risk guidelines are known as the Protective Action 36 Criteria (PAC) data set. PAC values for emergency planning of chemical release events are 37 based on the chemical exposure limit values provided by the following hierarchy. 38 39
• Acute Exposure Guideline Levels (AEGL). AEGLs are developed by the 40 U.S. Environmental Protection Agency. AEGLs are defined for five time periods: 41 10 minutes, 30 minutes, 60 minutes, 4 hours, and 8 hours. The 60-minute AEGL 42 values have been selected for use in the PAC data set. 43
44 • Emergency Response Planning Guidelines (ERPG). ERPGs are produced by the 45
American Industrial Hygiene Association Emergency Planning Committee. 46 47
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• Temporary Emergency Exposure Limits (TEEL). TEELs are developed by the DOE 1 Subcommittee on Consequence Assessment and Protective Actions. 2
3 The methodology in RPP-30604 allows input of the most recent PAC values into the calculation 4 of the toxicological source term. RPP-30604 uses Rev. 29 of the PAC values [DOE HSS, 5 Protective Action Criteria (PAC) with AEGLs, ERPGs, & TEELs: Rev. 29 for Chemicals of 6 Concern (06/2016)] supplemented with Rev. 28A PAC values [DOE HSS, Protective Action 7 Criteria (PAC) with AEGLs, ERPGs, & TEELs: Rev. 28A for Chemicals of Concern (02/2016)] 8 for utilized compounds that were removed from Rev. 29. For each chemical compound present 9 in a waste layer, the method compares the chemical compound concentration to its PAC, takes 10 the ratio of concentration to PAC value by compound, and adds the resulting ratios to generate 11 the unit sum of fractions (USOF) that defines the toxicological source term for that waste layer. 12 13 Revisions to PAC guidelines may result in changes to the USOF. As these revisions occur, the 14 specific accident analyses using toxicological source term USOF data are reviewed to determine 15 if the changes result in changes to the conclusions of the specific accident analyses (see 16 Section 5.5.3.4). 17 18 The waste to be transferred to and returned from the 242-A Evaporator is evaluated in a waste 19 compatibility assessment (based on sample data) and compared to the hazard and accident 20 analysis assumptions (see Section 5.5.3.4). The hazard and accident analysis assumptions are 21 required to be updated when necessary to bound the waste to be transferred to and returned from 22 the 242-A Evaporator. 23 24 3.4.1.2.2 Exposure Pathways. The toxicological source terms resulting from 242-A Evaporator 25 accidents are comprised of liquid and solid particulates and gases. Exposure is assumed to occur 26 via an airborne pathway, and exposure limits are based on the PAC values. Solids and liquids 27 are assumed to be dispersed as an aerosol. Exposure of skin and eyes is considered in the 28 development of the PAC values, but inhalation is the dominant exposure pathway. 29 30 3.4.1.2.3 Exposure Calculation Methods. The exposure calculation method is described in 31 RPP-13482. For accident analysis purposes, most toxic chemical mixes of concern at the 242-A 32 Evaporator (e.g., aerosolized waste, ammonia) have consequences that are acute (i.e., concentration 33 dependent) rather than being dependent on the total quantity taken up by the body (i.e., integrated 34 dose dependent). To determine whether a chemical consequence exceeds a guideline value, 35 therefore, the highest time-weighted average (TWA) concentration for any 15-min period (i.e., the 36 maximum or peak 15-min TWA concentration) is compared to the guideline value (RPP-13482). 37 38 The first step in the process is to determine the concentration of each component of the mixture 39 at the selected downwind receptor(s). In the DSA, the two receptors are nominally at 100 m and 40 the Hanford Site boundary. If the toxic material is released at some average rate over a period of 41
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time greater than 15 min, the peak concentration at the receptor is obtained directly from the 1 definition of the steady-state χ/Q' (Equation 3.4.1-3): 2 3
′
′=Q
QC χ (3.4.1-3) 4
5 where: 6 7 C = peak concentration (mg/m3) 8 Q' = toxic material release rate (mg/s) 9 χ/Q' = steady-state 1-hr dispersion coefficient (s/m3). 10 11 If the toxic material is released in less than 15 min, the release rate is determined by dividing the 12 total quantity released by the averaging time of 15 min (900 s). 13 14
Q' = Q/t (3.4.1-4) 15 where: 16 17 Q' = toxic material release rate (mg/s) 18 Q = total release of toxic material (mg) 19 t = averaging time (900 s). 20 21 Other useful forms of the equation for determining concentration are given in RPP-13482. 22 23 The second step is to divide the concentration of each component at the receptor by the 24 appropriate PAC value for that component. The resulting number is dimensionless. The basic 25 equation for concentration at the receptor in the steady-state model can be used to obtain the 26 SOFs for a mixture of chemicals as shown in Equation 3.4.1-5: 27 28
∑∑′
′
χ=
j j
j
j j
j
RGQ
QRGC
(3.4.1-5) 29
30 Where RGj is the risk guideline for the jth species. Reformulating the release rate, Q'j, in terms of 31 a volume release rate (L/s) times a waste concentration (mg/L) for each species, yields 32 33
∑∑
′
χ′=j j
j
j j
j
RGc
QV
RGC
34
35 Where V' is the volume release rate of the waste mixture (L/s) and cj is the concentration of 36 species j in the waste mixture (g/L x 106 = mg/m3). The summation on the right side of the 37 above equation is a dimensionless number referred to as the USOF for continuous releases. 38 39
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The SOFs for a particular consequence guideline and receptor is therefore given by 1 Equation 3.4.1-6: 2 3
( )USOFQ
VRGC
j j
j
′χ′=∑ (3.4.1-6) 4
5 The left side of the above equation is the SOF for the mixture at a specified receptor. If the SOF 6 for the mixture is less than or equal to 1, the concentration of the mixture to which the receptor is 7 exposed is within guidelines. If the number is greater than 1, the guideline is exceeded. 8 9 3.4.1.3 References. 10 11 Best-Basis Inventory. 12 13 DOE-HDBK-3010-94, 2000, Airborne Release Fractions/Rates and Respirable Fractions for 14
Nonreactor Nuclear Facilities, Change Notice No. 1, U.S. Department of Energy, 15 Washington, D.C. 16
17 DOE HSS PAC/TEEL, 2016, Protective Action Criteria (PAC) with AEGLs, ERPGs, & TEELs: 18
Rev. 28A for Chemicals of Concern (02/2016), U.S. Department of Energy, 19 Washington, D.C. 20
21 DOE HSS PAC/TEEL, 2016, Protective Action Criteria (PAC) with AEGLs, ERPGs, & TEELs: 22
Rev. 29 for Chemicals of Concern (06/2016), U.S. Department of Energy, 23 Washington, D.C. 24
25 DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor 26
Nuclear Facility Documented Safety Analyses, Change Notice No. 3, U.S. Department of 27 Energy, Washington, D.C. 28
29 Hader, W. E., 2015, “Direction to Implement the Planned Revision of the Hanford Site Boundary 30
to Support Alternate Land/Use Conveyance” (letter 15-NSD-0025/1503649 to C. A. 31 Simpson, Washington River Protection Solutions LLC, August 27), U.S. Department of 32 Energy, Office of River Protection, Richland, Washington. 33
34 ICRP-68, 1994, Dose Coefficients for Intakes of Radionuclides by Workers – Replacement of 35
ICRP Publication 61, ICRP Publication 68, Annals of the ICRP, Vol. 24, Number 4, 36 Elsevier Science, Tarrytown, New York. 37
38 ICRP-71, 1996, Age Dependent Doses to Members of the Public from Intake of Radionuclides 39
Part 4 Inhalation Dose Coefficients, ICRP Publication 71, Annals of the ICRP, Vol. 24, 40 Number 4, Elsevier Science, Tarrytown, New York. 41
42
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ICRP-72, 1996, Age Dependent Doses to Members of the Public from Intake of Radionuclides 1 Part 5 Compilation of Ingestion and Inhalation Dose Coefficients, ICRP Publication 72, 2 Annals of the ICRP, Vol. 24, Number 4, Elsevier Science, Tarrytown, New York. 3
at Nuclear Power Plants,” U.S. Nuclear Regulatory Commission, Washington, D.C. 6 7 RPP-5924, 2007, Radiological Source Terms for Tank Farms Safety Analysis, Rev. 5, 8
CH2M HILL Hanford Group, Inc., Richland, Washington. 9 10 RPP-13482, 2015, Atmospheric Dispersion Coefficients and Radiological and Toxicological 11
Exposure Methodology for Use in Tank Farms, Rev. 8, Washington River Protection 12 Solutions LLC, Richland, Washington. 13
14 RPP-30604, 2016, Tank Farms Safety Analyses Chemical Source Term Methodology, Rev. 6, 15
Washington River Protection Solutions LLC, Richland, Washington. 16 17 Scott, W. B., 1995, “Clarification of Hanford Site Boundaries for Current and Future Use in 18
Safety Analyses,” (letter 9504327 to Director, Pacific Northwest Laboratory, and 19 President, Westinghouse Hanford Company, September 26), U.S. Department of Energy, 20 Richland Operations Office, Richland, Washington. 21
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T3.4.1 1 Table 3.4.1-1. Site Boundary Distances.
Sector Minimum distance within a 45º sector (m) S 15,360
SSW 15,360 SW 13,200
WSW 11,100 W 11,100
WNW 11,100 NW 10,800
NNW 8,690 N 8,690
NNE 8,670 NE 10,430
ENE 10,530 E 11,160
ESE 15,190 SE* 12,520 SSE 15,360
*As described in RPP-13482(a), Appendix R, the distance to the SE Sector site boundary is conservatively estimated to have reduced from 21,050 to 12,520 meters due to the Hanford Site land conveyance by the DOE (Hader 2015(b)). (a) Hader, W. E., 2015, “Direction to Implement the Planned Revision of the Hanford Site Boundary to Support Alternate Land/Use Conveyance” (letter 15-NSD-0025/1503649 to C. A. Simpson, Washington River Protection Solutions LLC, August 27), U.S. Department of Energy, Office of River Protection, Richland, Washington. (b) RPP-13482, 2015, Atmospheric Dispersion Coefficients and Radiological and Toxicological Exposure Methodology for Use in Tank Farms, Rev. 8, Washington River Protection Solutions LLC, Richland, Washington.
1 Table 3.4.1-3. Dispersion Coefficients for 200 Area Facilities to
Onsite Receptor at 100 m.
Meteorological condition 1-hr χ/Q'
(s/m3)
2-hr χ/Q' with plume meander
(s/m3)a
8-hr χ/Q' with plume meander (s/m3)a
95th Percentile overall 1.09 E-2b 9.40 E-3 5.58 E-3 Annual average maximum sector
4.03 E-4 -- --
50th Percentile maximum sector
5.33 E-3 2.27 E-3 1.71 E-3
Note:
a The 2-hr and 8-hr χ/Qs include the effects of plume meander averaged over 2 hr and 8 hr, respectively.
b Includes the effects of mixing the release plume with the building wake. 2 3 4
Table 3.4.1-4. Dispersion Coefficients for 200 Area Facilities to Hanford Site Boundary Receptor.
Meteorological condition 1-hr χ/Q' (s/m3)
2-hr χ/Q' with plume meander
(s/m3)a
8-hr χ/Q' with plume meander (s/m3)a
95th Percentile overall 2.21 E-5b 1.74 E-5 7.90 E-6 Annual average maximum sector
1.47 E-7 -- --
50th Percentile maximum sector
4.48 E-6 3.83 E-6 2.23 E-6
Note:
a The 2-hr and 8-hr χ/Qs include the effects of plume meander averaged over 2 hr and 8 hr, respectively.
b Includes the effects of mixing the release plume with the building wake. 5
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3.4.2 Design Basis Accidents 1 2 This section presents the quantitative analyses of the potential radiological consequences to the 3 offsite public from the design basis accidents (DBA). It is important to note that the concept of a 4 DBA evolved in the commercial nuclear industry and typically applies to high consequence 5 accidents that are analyzed during the planning stages of new facilities. It is acknowledged that 6 the DBA concept is not strictly applicable to many U.S. Department of Energy (DOE) facilities 7 because the original design bases are not well understood. Nonetheless this documented safety 8 analysis (DSA) uses the term DBA for simplicity to identify bounding accidents. 9 10 Following the accident selection methodology described in Section 3.3.2.3.1, three DBAs were 11 selected for comparison to the DOE-STD-3009-94, Preparation Guide for U.S. Department of 12 Energy Nonreactor Nuclear Facility Documented Safety Analyses, Appendix A, Evaluation 13 Guideline of 25 rem total effective dose (TED). The Evaluation Guideline is used for 14 comparison to the estimated dose received by a hypothetical maximally-exposed offsite 15 individual at the Hanford Site boundary. For most DBAs, an exposure duration of 2 hr is used, 16 but for release scenarios that are especially slow to develop, the exposure duration may be 17 extended to 8 hr. The purpose of the dose calculations and comparison to the Evaluation 18 Guideline is to determine whether hazards posed by the 242-A Evaporator warrant the 19 designation of safety-class structures, systems, and components (SSC). 20 21 Of the three identified DBAs, two involve operational events. The following two operational 22 accidents are selected primarily based on release characteristics of the representative accidents 23 (see Section 3.3.2.3.1). 24 25
• Flammable Gas Accidents 26 • Waste Leaks and Misroutes 27
28 The remaining DBA analyzed for comparison to the Evaluation Guideline is natural events. 29 30 Unmitigated consequence calculations were performed for these DBAs and, in accordance with 31 DOE-STD-3009-94, no credit was taken for active safety features or for passive safety features 32 that produce a leakpath reduction in source term. In this regard it is important to note that the 33 unmitigated release calculation represents a theoretical condition as opposed to an evaluation of 34 the current operational configuration of the 242-A Evaporator. 35 36 With respect to accident frequency, there is no predetermined cutoff value, such as 1 x 10-6/yr, 37 for excluding low frequency operational accidents from consideration. Therefore, there is no 38 discussion of frequency in the evaluation of the operational accidents. However, estimated 39 frequencies for the operational accidents are discussed in the corresponding sections for the 40 representative accidents (e.g., frequencies of flammable gas accidents are discussed in 41 Section 3.3.2.4.1). There is a frequency cutoff for external events of 1 x 10-6/yr, conservatively 42 calculated; and 1 x 10-7/yr, realistically calculated. Frequency analysis of the aircraft crash, 43 documented in Section 3.3.2.4.4, indicates that the frequency is less than 1 x 10-6/yr and thus the 44 accident was not analyzed for comparison to the Evaluation Guideline. Natural events are 45 evaluated in accordance with the requirements and guidelines provided in DOE O 420.1C, 46 Facility Safety and the associated DOE Standards. 47
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1 The unmitigated consequence analysis and the comparison to the Evaluation Guideline are 2 presented in the following subsections. None of the analyzed DBAs challenge the Evaluation 3 Guideline. Therefore, no safety-class SSCs are required for the 242-A Evaporator. In addition, 4 the accident analysis of the DBAs was compared with DOE/EIS-0189, Tank Waste Remediation 5 System, Hanford Site, Richland, Washington, Final Environmental Impact Statement, and no 6 significant discrepancies were identified. 7 8 Additional information on the three DBAs is provided in the corresponding sections for the 9 representative accidents (i.e., Sections 3.3.2.4.1, 3.3.2.4.3, and 3.3.2.4.5). 10 11 References 12 13 DOE/EIS-0189, 1996, Tank Waste Remediation System, Hanford Site, Richland, Washington, 14
Final Environmental Impact Statement, U.S. Department of Energy, Washington, D.C., 15 and Washington State Department of Ecology. 16
17 DOE O 420.1C, Chg 1, 2015, Facility Safety, U.S. Department of Energy, Washington, D.C. 18 19 DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor 20
Nuclear Facility Documented Safety Analyses, Change Notice No. 3, U.S. Department of 21 Energy, Washington, D.C. 22
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3.4.2.1 Flammable Gas Accidents. This section summarizes the accident analysis of 1
potential radioactive material releases due to flammable gas accidents for comparison to the 2
DOE-STD-3009-94, Preparation Guide for U.S. Department of Energy Nonreactor Nuclear 3
Facility Documented Safety Analyses, Appendix A, Evaluation Guideline of 25 rem total 4
effective dose (TED). The bounding flammable gas accident is a flammable gas detonation in 5
the C-A-1 vessel. The calculations supporting the consequences presented here are documented 6
in RPP-48050, Technical Basis for Releases from Deflagration or Detonation in the 242-A 7
Evaporator. 8
9
3.4.2.1.1 Scenario Development. Flammable gases are generated by waste in the C-A-1 vessel; 10
residual waste in waste feed transfer piping, waste slurry transfer piping, and C-A-1 vessel drain 11
(dump) piping; and waste that may be misrouted to the process condensate system, including 12
process condensate tank TK-C-100; the steam condensate system; and the raw water system. In 13
the absence of adequate ventilation, the generated flammable gases can accumulate to 14
concentrations that exceed the lower flammability limit (LFL). Given that the LFL is reached, a 15
deflagration or detonation can occur if an ignition source is present. 16
17
The potential offsite radiological consequences of a flammable gas accident in the C-A-1 vessel 18
and process condensate tank TK-C-100 are calculated in RPP-48050. The bounding flammable 19
gas accident occurs in the C-A-1 vessel because of the larger headspace where flammable gases 20
generated by the waste in the C-A-1 vessel can accumulate. Flammable gas accidents in waste 21
feed transfer piping, waste slurry transfer piping, C-A-1 vessel drain (dump) piping; and in the 22
piping and other components of the process and steam condensate systems, and in the raw water 23
system, are only significant facility worker hazards because of the lower potential volume of 24
flammable gases that can accumulate. 25
26
The bounding flammable gas accident is, therefore, a flammable gas detonation in the C-A-1 27
vessel that damages the vessel with the aerosolized waste from the detonation released directly to 28
the atmosphere. A detonation was selected rather that a deflagration, because the faster flame 29
speed of a detonation can potentially result in a larger release of respirable material. 30
31
3.4.2.1.2 Source Term Analysis. The waste aerosol release for this analysis is based on the 32
conservative DOE-HDBK-3010-94, Airborne Release Fractions/Rates and Respirable Fractions 33
for Nonreactor Nuclear Facilities, trinitrotoluene (TNT) equivalent correlation. The 34
DOE-HDBK-3010-94 TNT equivalent correlation assumes that the total available energy from 35
the combustion of hydrogen in the C-A-1 vessel headspace converted to grams of TNT results in 36
the release of respirable waste in grams equivalent to the grams of TNT. To calculate the total 37
available energy, the flammable gas concentration in the C-A-1 vessel headspace is assumed to 38
be 30% hydrogen by volume, which is the stoichiometric mixture of hydrogen and air where the 39
maximum explosive energy potential occurs. The assumed C-A-1 vessel headspace volume is 40
18,856 gal (2,521 ft3), which includes the headspace volume of the C-A-1 vessel at the lowest 41
operational volume of waste in the C-A-1 vessel (23,000 gal) and the volume of additional 42
components that make up the extended vapor space beyond the evaporator vessel. Using the 43
DOE-HDBK-3010-94 TNT correlation, this results in an estimated release from a C-A-1 vessel 44
headspace detonation of 59.3 kg, or approximately 45.6 L of respirable waste assuming a waste 45
density of 1.3 kg/L. 46
47
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Evaporator slurry is not expected to contain significant amounts of entrained solids. However, 1
solids content of up to 1 vol% is evaluated as a bounding case. The offsite radiological unit-liter 2
dose (ULD) for this analysis is based on the worst case double-shell tank (DST) waste layers 3
reported in the Best-Basis Inventory (BBI). This is reasonably conservative given that the waste 4
types stored in DSTs includes those that have been processed through the 242-A Evaporator and 5
concentrated to higher levels than planned for future 242-A Evaporator operations, and the ULD 6
for the solids are based on the worst case DST waste sludge and waste sludge is not processed 7
through the 242-A Evaporator. The values used in the calculation are: 8
9
Offsite ULD (liquids) = 1.5 x 103 Sv/L 10
Offsite ULD (solids) = 2.9 x 105 Sv/L 11
12
3.4.2.1.3 Consequence Analysis. The offsite radiological dose is calculated as shown in 13
Equation 3.4.2.1-1: 14
15
Dinh = Q * χ/Q' * R * ULDinh (3.4.2.1-1) 16
17
where: 18
19
Q = source term (respirable quantity released) (45.6 L) 20
R = receptor breathing rate (3.33 x 10-4 m3/sec) (Section 3.4.1) 23
ULDinh = offsite unit-liter dose for inhalation of waste (Sv/L). 24
25
The ULD for the liquid/solid mixture is calculated in Equation 3.4.2.1-2: 26
27
ULD = F * ULDsol + (1-F) * ULDliq 3.4.2.1-2) 28
29
where: 30
F = fraction of waste (by volume) composed of solids (1 vol%) 31
ULDsol = unit-liter dose for inhalation of solids (2.9 x 105 Sv/L) 32
ULDliq = unit-liter dose for inhalation of liquids (1.5 x 103 Sv/L). 33
34
Then: 35
ULD = [(0.01) (2.9 x 105 Sv/L)] + [(1 - 0.01) (1.5 x 103Sv/L)] = 4.4 x103 Sv/L. 36
37
The offsite radiological dose due to aerosol release is then calculated as follows: 38
39
Dinh= (45.6 L) (2.21 x 10-5 sec/m3) (3.33 x 10-4) m3/sec) (4.4 x 103 Sv/L) 40
Dinh = 1.5 x 10-3 Sv 41
Dinh =1.5 x10-1 rem 42
43
A sensitivity analysis in RPP-48050 also showed that the offsite radiological dose is < 5 rem 44
assuming the total volume of the C-A-1 vessel and extended vapor space reached a flammable 45
gas concentration of 30% hydrogen by volume (the stoichiometric mixture of hydrogen and air 46
that produces the maximum explosive energy potential). 47
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1
3.4.2.1.4 Comparison to the Evaluation Guideline. The offsite radiological consequences for 2
the bounding flammable gas accident (a flammable gas detonation in the C-A-1 vessel) of 3
0.15 rem does not challenge the 25 rem DOE-STD-3009-94, Appendix A, Evaluation Guideline 4
(i.e., < 5 rem). 5
6
3.4.2.1.5 Summary of Safety-Class Structures, Systems, and Components and Technical 7 Safety Requirement Controls. Because the offsite radiological consequences of flammable gas 8
accidents do not challenge the 25 rem Evaluation Guideline, no safety-class structures, systems, 9
and components (SSC) or Specific Administrative Controls (SAC) are required, and no 10
assumptions of the analysis require technical safety requirement (TSR) coverage. 11
12
3.4.2.1.6 References. 13 14
Best Basis Inventory (BBI). 15
16
DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor 17
Nuclear Facility Documented Safety Analyses, Change Notice No. 3, U.S. Department of 18
Energy, Washington, D.C. 19
20
DOE-HDBK-3010-94, 2000, Airborne Release Fractions/Rates and Respirable Fractions for 21
Nonreactor Nuclear Facilities, Change Notice No. 1, U.S. Department of Energy, 22
Washington, D.C. 23
24
RPP-48050, 2014, Technical Basis for Releases from Deflagration or Detonation in the 242-A 25
Evaporator, Rev. 1, Washington River Protection Solutions LLC, Richland, Washington. 26
27
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3.4.2.2 Waste Leaks and Misroutes. This section summarizes the accident analysis of 1
potential radioactive material releases due to waste leaks and misroutes for comparison to the 2
DOE-STD-3009-94, Preparation Guide for U.S. Department of Energy Nonreactor Nuclear 3
Facility Documented Safety Analyses, Appendix A, Evaluation Guideline of 25 rem total 4
effective dose (TED). The bounding waste leak is a fine spray leak during a waste transfer using 5
slurry pump P-B-2. The calculations supporting the consequences presented here are 6
documented in RPP-13750, Waste Transfer Leaks Technical Basis Document, Attachment A14. 7
8
3.4.2.2.1 Scenario Development. Waste leaks (ranging from a fine spray to a large break) can 9
occur within the 242-A Evaporator. Waste in the 242-A Evaporator C-A-1 vessel (includes the 10
E-A-1 reboiler and recirculation line) and the waste recirculated in the C-A-1 vessel by 11
recirculation pump P-B-1 is under hydrostatic pressure only. Pumped (pressurized) waste exists 12
in the feed line during waste transfers to the C-A-1 vessel from the tank farms using feed pump 13
241-AW-P-102-1, and in the slurry line during waste transfers from the C-A-1 vessel to the tank 14
farms using slurry pump P-B-2. Waste may also be misrouted to the process condensate system, 15
the steam condensate system, and the raw water system due to misroutes (see Section 3.3.2.4.2). 16
17
The potential offsite radiological consequences of a waste leak vary based on the driving 18
pressure behind the leak. Based on the analysis contained in RPP-13750, the bounding accident 19
scenario for the offsite radiological consequences is the fine spray leak during a waste transfer 20
using slurry pump P-B-2 because this pump has the highest shutoff head (i.e., the slurry pump 21
P-B-2 shutoff head is higher than the feed pump 241-AW-P-102-1, the process condensate pump 22
P-C-100, the process condensate recycle pump P-C-106, and the steam condensate sample pump 23
P-RC-1). (Note: There are no credible pressurized waste spray leaks involving raw water 24
pumps.) 25
26
3.4.2.2.2 Source Term Analysis. For a fine spray leak, the direct release of aerosol into the air 27
is determined using an iterative process to determine the flow rate of waste through the crack. 28
The key parameters and assumptions required as input to the crack pressure and leak rate 29
iteration include crack size, solids fraction, transfer line configuration, and waste transfer pump 30
performance (i.e., pump characteristic curve). These parameters and assumptions are 31
summarized below. Additional details are presented in RPP-13750, Attachment A14, and are 32
based on the methodology described in RPP-37897, Waste Transfer Leak Analysis Methodology 33
Description Document. 34
35
Crack Size. For the fine spray leak scenario, the crack length is assumed be 3 in., and the 36
crack width is selected to maximize the amount of fine waste aerosol spray produced by the 37
leak. The crack length of 3 in. is selected as reasonably conservative based on review of 38
previous experience with waste transfer line leaks. The crack width is selected based on a 39
Weber Number criterion, as described in RPP-37897. Assuming either a larger or smaller 40
crack width would result in reduced fine aerosol production. 41
42
Solids Fraction. Evaporator slurry is not expected to contain significant amounts of 43
entrained solids. However, solids content of up to 1 vol% is evaluated as a bounding case. 44
45
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Transfer Line Configuration. It is assumed that there is a blockage in the transfer line 1
downstream of the crack location, and that there is minimal pressure loss between the waste 2
transfer pump and the crack. These assumptions maximize the pressure at the crack. 3
4
Waste Transfer Pump Performance. Unmitigated pump performance for waste transfer 5
pump (slurry pump) P-B-2 is described in RPP-CALC-23897, VFD Driven Induction 6
Motor/Pump Performance Evaluation. The head versus flow data for a waste specific 7
gravity of 1.3 is used for this analysis. A waste specific gravity of 1.3 is selected to be 8
representative of a double-shell tank (DST) supernatant with a low viscosity (conservative 9
for aerosolizing waste) and high unit-liter dose (ULD). The head/flow performance at a 10
waste specific gravity of 1.3 is also more conservative than at a higher specific gravity. 11
(Note: The specific gravity value assumed has very little effect on the calculated 12
consequences.) The waste transfer pump performance data is contained in 13
RPP-CALC-23897, Table 13. 14
15
Leak Rate. The flow rate of waste through the leak is calculated using an iterative 16
procedure that balances the flow rate and pressure produced by the waste transfer pump with 17
the flow rate and pressure at the crack location, given that pressure drop occurs between the 18
pump and the leak. 19
20
For the bounding fine spray leak during a waste transfer using slurry pump P-B-2, the calculated 21
leak rate for the direct aerosol release is 83 gal/min. The respirable fraction of the fine spray 22
release is calculated based on the Rosin-Rammler particle size distribution formula, as described 23
in RPP-37897. Major parameters that affect the particle size distribution include the crack size, 24
leak pressure, and viscosity of the waste. A correction for aerosol particle evaporation is also 25
included. 26
27
In addition to the direct aerosol release from the fine spray leak, there is a minor contribution to 28
the release from aerosol generated by the splash and splatter from the waste falling onto surfaces. 29
The respirable release due to splash and splatter is based on an airborne release fraction (ARF) 30
and a respirable fraction (RF) that when multiplied together equals 8.7 x 10-6 (see RPP-37897). 31
A waste pool is also assumed to form in the pump room sump, but there is no wind entrainment 32
from this pool and no gamma shine reaches the offsite receptor. 33
34
The accident duration is assumed to be 8 hr. The fine spray leak produces 26 L of respirable 35
waste aerosol due to the fine spray release and 1.3 L of respirable waste aerosol due to splash 36
and splatter, for a total respirable release of 27 L (rounded to two significant figures). No 37
aerosol attenuation is assumed to occur as the waste aerosols migrate from where the aerosols are 38
generated in the pump room until they exit the facility (e.g., from the ventilation system stack). 39
Therefore, the leak path factor is 1.0. 40
41
The offsite radiological (ULD) for this analysis is based on the worst case DST waste layers 42
reported in the Best-Basis Inventory (BBI). This is reasonably conservative given that the waste 43
types stored in DSTs includes those that have been processed through the 242-A Evaporator and 44
concentrated to higher levels than planned for future 242-A Evaporator operations, and the ULD 45
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for the solids are based on the worst case DST waste sludge and waste sludge is not processed 1
through the 242-A Evaporator. The values used in the calculation are: 2
3
Offsite ULD (liquids) = 1.5 x 103 Sv/L 4
Offsite ULD (solids) = 2.9 x 105 Sv/L 5
6
Solids content of up to 1 vol% is evaluated as a bounding case. 7
8
3.4.2.2.3 Consequence Analysis. The offsite radiological dose is calculated as shown in 9
Equation 3.4.2.2-1: 10
11
Dinh = Q * χ/Q' * R * ULDinh (3.4.2.2-1) 12
13
where: 14
15
Q = source term (respirable quantity released) (27 L) 16
dispersion coefficient (7.9 x 10-6 sec/m3) (Section 3.4.1) 18
R = receptor breathing rate (3.33 x 10-4 m3/sec) (Section 3.4.1) 19
ULDinh = offsite unit-liter dose for inhalation of waste (Sv/L). 20
21
The ULD for the liquid/solid mixture is calculated in Equation 3.4.2.2-2: 22
23
ULD = F * ULDsol + (1-F) * ULDliq (3.4.2.2-2) 24
25
where: 26
27
F = fraction of waste (by volume) composed of solids (1 vol%) 28
ULDsol = unit-liter dose for inhalation of solids (2.9 x 105 Sv/L) 29
ULDliq = unit-liter dose for inhalation of liquids (1.5 x 103 Sv/L). 30
31
Then: 32
ULD = [(0.01) (2.9 x 105 Sv/L)] + [(1 - 0.01) (1.5 x 103Sv/L)] = 4.4 x103 Sv/L. 33
34
The offsite radiological dose due to aerosol release is then calculated as follows: 35
36
Dinh= (27 L) (7.9 x 10-6 s/m3) (3.33 x 10-4) m3/) (4.4 x 103 Sv/L) 37
Ds= 3.1 x 10-4 Sv 38
Ds=3.1 x10-2 rem 39
40
3.4.2.2.4 Comparison to the Evaluation Guideline. The offsite radiological consequence for 41
the bounding waste leak or misroute (a fine spray leak during a waste transfer using slurry pump 42
P-B-2) of 0.031 rem does not challenge the 25 rem DOE-STD-3009-94, Appendix A, Evaluation 43
Guideline (i.e., < 5 rem). 44
45
3.4.2.2.5 Summary of Safety Structures, Systems, and Components and Technical Safety 46 Requirements Controls. Because the offsite radiological consequences of waste leaks and 47
misroutes do not challenge the 25 rem Evaluation Guideline, no safety-class structures, systems, 48
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and components (SSC) or Specific Administrative Controls (SAC) are required, and no 1
assumptions of the analysis require technical safety requirement (TSR) coverage. 2
3
3.4.2.2.6 References. 4 5
Best Basis Inventory (BBI). 6
7
DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor 8
Nuclear Facility Documented Safety Analyses, Change Notice No. 3, U.S. Department of 9
Energy, Washington, D.C. 10
11
RPP-13750, 2013, Waste Transfer Leak Technical Basis Document, Rev. 40, Washington River 12
Washington River Protection Solutions LLC, Richland, Washington. 16
17
RPP-CALC-23897, VFD Driven Induction Motor/Pump Performance Evaluation, as amended, 18
Washington River Protection Solutions LLC, Richland, Washington. 19
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3.4.2.3 Natural Events. This section summarizes the accident analysis of potential 1 radioactive material releases due to natural events for comparison to the DOE-STD-3009-94, 2 Preparation Guide for U.S. Department of Energy Nonreactor Nuclear Facility Documented 3 Safety Analyses, Appendix A, Evaluation Guideline of 25 rem total effective dose (TED). The 4 bounding natural event is a design (evaluation) basis earthquake. 5 6 U.S. Department of Energy (DOE) requirements and guidelines for the mitigation of natural 7 phenomena hazards at DOE facilities are provided in DOE O 420.1C, Facility Safety and the 8 associated DOE Standards. Based on these DOE requirements and guidelines, seismic design 9 categories and seismic hazard exceedance probabilities are shown in RPP-13033, Tank Farms 10 Documented Safety Analysis, Chapter 1.0, Table 1.4.3.7.1-1, which are also applicable to the 11 242-A Evaporator. Per Table 1.4.3.7.1-1, the 242-A Evaporator, which is a Hazard Category 2 12 facility (see Section 3.3.2.2), will use Seismic Design Category (SDC)-2 as the design basis 13 earthquake. The earthquake load design for SDC-2 is to follow International Building Code 14 (IBC 2015) Risk Category IV – 2/3 Maximum Considered Earthquake ground motion with an 15 importance factor of 1.5. Note that a seismic event of this magnitude has never been recorded at 16 the Hanford Site. A Performance Category 2 classification was used as the design (evaluation) 17 basis in RPP-RPT-52517, 242-A Evaporator Facility Assessment for Performance Category 2 18 Natural Phenomena Hazards. 19 20 3.4.2.3.1 Scenario Development. The damage to the 242-A Evaporator and the resulting 21 uncontrolled releases of radioactive material from a design basis earthquake is uncertain, but is 22 conservatively bounded by an accident scenario that includes possible flammable gas accidents and 23 waste leaks and misroute. (Note: These are the bounding operational accidents analyzed for offsite 24 radiological consequences in Sections 3.4.2.1 and 3.4.2.2, respectively. As described in 25 Section 3.3.2.3.1 other representative accidents have limited potential for offsite radiological 26 consequences. While some of these other representative accidents could be caused by a design 27 basis earthquake, the resultant radioactive material releases and offsite radiological consequences 28 would be small compared to the consequences of the bounding flammable gas accident or waste 29 leak.) 30 31 An earthquake could cause a flammable gas deflagration or detonation in the C-A-1 vessel 32 headspace. A C-A-1 vessel detonation is the bounding flammable gas accident for which the 33 offsite radiological consequences are calculated in Section 3.4.2.1. An earthquake could also 34 cause waste leaks or misroutes. The bounding offsite radiological consequences for a waste leak 35 or misroute (i.e., fine spray leak during a waste transfer using slurry pump P-B-2) are calculated 36 in Section 3.4.2.2. However, a flammable gas accident would not immediately occur from the 37 earthquake because of the time required for the flammable gases generated by the waste in the 38 C-A-1 vessel to accumulate to 100% of the lower flammability limit (LFL) (days to weeks) for a 39 deflagration and significantly longer for a detonation. Therefore, the consequences of a 40 flammable gas accident and a waste leak or misroute are not concurrent. 41 42 3.4.2.3.2 Source Term Analysis. The source term analyses for the bounding flammable gas 43 accident and the bounding waste leak and misroute are described in Sections 3.4.2.1.2 and 44 3.4.2.2.2, respectively. These bounding source terms are used to qualitatively estimate the 45 cumulative releases of radioactive material from flammable gas accidents and waste leaks and 46 misroute caused by a design basis accident. 47
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1 3.4.2.3.3 Consequence Analysis. Summarized in Table 3.4.2.3-1 are the calculated offsite 2 radiological consequences for the bounding flammable gas accident and the bounding waste leak 3 and misroute. Although a design basis earthquake may cause multiple accidents (e.g., flammable 4 gas accidents, waste leaks and misroutes), it is not reasonable to expect that all of the releases 5 would occur in the same time frame or be the highest estimated release for the individual 6 accidents. That is, a waste leak would occur at the time of the event or shortly thereafter, 7 whereas a flammable gas deflagration would occur days to weeks later because of the time 8 required for flammable gases to accumulate to the LFL. For the initiated accidents there would 9 be a range of consequences below the reasonably conservative consequences estimated for each 10 individual accident. For this reason, it is judged that, even if natural events initiated multiple 11 accidents, the cumulative effects would be < 1 rem. 12 13 3.4.2.3.4 Comparison to the Evaluation Guideline. The offsite radiological consequences for 14 the bounding natural event (a design basis earthquake) does not challenge the 25 rem TED in 15 DOE-STD-3009-94, Appendix A, Evaluation Guideline (i.e., < 5 rem). 16 17 3.4.2.3.5 Summary of Safety Structures, Systems, and Components and Technical Safety 18 Requirement Controls. Because the offsite radiological consequences of natural events do not 19 challenge the 25 rem Evaluation Guideline, no safety-class structures, systems, and components 20 (SSC) or Specific Administrative Controls (SAC) are required, and no assumptions of the 21 analysis require technical safety requirement (TSR) coverage. 22 23 3.4.2.3.6 References. 24 25 DOE O 420.1C, Chg 1, 2015, Facility Safety, U. S. Department of Energy, Washington, D.C. 26 27 DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor 28
Nuclear Facility Documented Safety Analyses, Change Notice No. 3, U.S. Department of 29 Energy, Washington, D.C. 30
31 IBC, 2015, International Building Code, International Code Council, Inc., Country Club Hills, 32
Illinois. 33 34 RPP-13033, Tank Farms Documented Safety Analysis, as amended, Washington River Protection 35
Natural Phenomena Hazards, Rev. 0, Washington River Protection Solutions LLC, 39 Richland, Washington. 40
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T3.4.2.3 1 Table 3.4.2.3-1. Offsite Radiological Consequences for Bounding Accidents
Postulated to Result from a Design Basis Earthquake. Bounding accident MOI dose (TED)
Flammable gas accident (C-A-1 vessel flammable gas accident) (see Section 3.4.2.1)
0.15 rem
Waste leak or misroute (fine spray leak during a waste transfer using waste transfer pump P-B-2) (see Section 3.4.2.2)
0.031 rem
Notes: MOI = maximally-exposed offsite individual. TED = total effective dose.
2
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3.4.3 Beyond Design Basis Accidents 1 2 As stated in DOE-STD-3009-94, Preparation Guide for U.S. Department of Energy Nonreactor 3 Nuclear Facility Documented Safety Analyses, “The Rule requires consideration of the need for 4 analysis of accidents which may be beyond the design basis of the facility to provide a 5 perspective of the residual risk associated with the operation of the facility.” Beyond design 6 basis accidents (DBA) serve as the bases for cost-benefit considerations if consequences exceed 7 the evaluation guidelines. Cost-benefit analysis, if required, is performed outside the 8 documented safety analysis (DSA). 9 10 As discussed below, considering the need for beyond DBA operational accidents and natural 11 phenomenon events, it has been determined that no beyond DBA analysis is needed (per 12 DOE-STD-3009-94, beyond DBAs are not evaluated for man-made external events. 13 14 3.4.3.1 Operational Beyond Design Basis Accidents. As discussed in DOE-STD-3009-94, 15 operational beyond DBAs are simply those operational accidents with more severe conditions or 16 equipment failures than are estimated for the corresponding DBA. The operational accidents 17 analyzed in Section 3.3.2.4 are flammable gas accidents and waste leaks and misroutes. These 18 accidents were analyzed in accordance with DOE-STD-3009-94, Appendix A, Evaluation 19 Guideline, which, consistent with the guidelines for beyond DBA analyses, stipulates that there 20 is no predetermined frequency cutoff for excluding low frequency operational accidents. 21 Accordingly, the accidents as analyzed in Section 3.4.2 already assume severe conditions and 22 equipment failures. 23 24 3.4.3.1.1 Flammable Gas Accidents. The bounding flammable gas accident analyzed in 25 Section 3.2.4.1 is a detonation in the C-A-1 vessel that results in a 0.15 rem offsite radiological 26 consequence. The analysis of the C-A-1 vessel detonation used the conservative 27 DOE-HDBK-3010-94, Airborne Release Fractions/Rates and Respirable Fractions for 28 Nonreactor Nuclear Facilities, trinitrotoluene (TNT) equivalent correlation and conservatively 29 assumed the C-A-1 vessel and extended vapor space reached a flammable gas concentration of 30 30% hydrogen by volume (the stoichiometric mixture of hydrogen and air that produces the 31 maximum explosive energy potential). 32 33 Based on the above considerations, and the fact that the DBA consequence does not challenge 34 the 25 rem total effective dose (TED) Evaluation Guideline (i.e., < 5 rem), it is concluded that a 35 beyond DBA flammable gas accident analysis is not needed because the residual risk is low. 36 37 3.4.3.1.2 Waste Leaks and Misroutes. The bounding waste leak and misroute analyzed in 38 Section 3.4.2.2 is a fine spray leak during a waste transfer using slurry pump P-B-2 that results in 39 a 0.031 rem offsite radiological consequence. The fine spray leak analyzed in Section 3.4.2.2 40 assumes a crack length of 3 in. and an optimal crack width selected to maximize the amount of 41 fine waste aerosol spray produced by the leak. Assuming either a larger or smaller crack width 42 would result in reduced fine aerosol production and lower consequences. The analysis also 43 assumed unmitigated slurry pump P-B-2 performance, and a blockage in the transfer line 44 downstream of the crack location and minimal pressure loss between the pump and crack 45 location to maximizes the pressure at the crack. 46 47
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Based on the above considerations, and the fact that the DBA consequence does not challenge 1 the 25 rem TED Evaluation Guideline (i.e., < 5 rem), it is concluded that a beyond DBA waste 2 leak and misroute analysis is not needed because the residual risk is low. 3 4 3.4.3.2 Natural Event Beyond Design Basis Accidents. As discussed in DOE-STD-3009-94, 5 beyond DBA natural events are defined by the initiating frequency (i.e., a frequency of occurrence 6 less than the DBA frequency of occurrence). An earthquake is the natural event (i.e., natural 7 phenomena hazard) with the highest potential for consequences at the tank farms because it can 8 initiate multiple concurrent accidents (e.g., flammable gas accidents, waste transfer leaks). 9 10 For the 242-A evaporator, which is a Hazard Category 2 facility, Seismic Design Category 11 (SDC)-2 defines the design (i.e., evaluation) basis earthquake. The less frequent, higher peak 12 horizontal ground acceleration earthquakes corresponding to SDC-3 and SDC-4 are beyond 13 DBA earthquakes. 14 15 Because the damage to the 242-A Evaporator and the resulting uncontrolled releases of 16 radioactive material from an earthquake are uncertain, the analysis in Section 3.4.2.3 17 conservatively assumes that multiple accidents occur, including flammable gas accidents and 18 waste leaks and misroutes. High magnitude earthquakes will not increase the consequences of 19 the bounding flammable gas accident or the bonding waste leak and misroute analyzed in 20 Sections 3.4.2.1 and 3.4.2.2. Therefore, even with consideration of the cumulative consequences 21 from potential multiple events initiated from an earthquake, the 25 rem Evaluation Guideline is 22 not challenged and encompasses not only the SDC-2 design basis earthquake, but also the 23 beyond DBA SDC-3 and SDC-4 earthquakes. Based on this, further analysis of beyond DBA 24 natural events is not needed. 25 26 3.4.3.3 References. 27 28 DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor 29
Nuclear Facility Documented Safety Analyses, Change Notice No. 3, U.S. Department of 30 Energy, Washington, D.C. 31
32 DOE-HDBK-3010-94, 2000, Airborne Release Fractions/Rates and Respirable Fractions for 33
Nonreactor Nuclear Facilities, Change Notice No. 1, U.S. Department of Energy, 34 Washington, D.C. 35
COMPONENTS .................................................................................................. 4-3 9 4.4.1 C-A-1 Vessel Flammable Gas Control System ....................................... 4-3 10 4.4.2 C-A-1 Vessel Waste High Level Control System.................................. 4-14 11 4.4.3 C-A-1 Vessel Seismic Dump System .................................................... 4-23 12 4.4.4 E-A-1 Reboiler ....................................................................................... 4-31 13 4.4.5 Backflow Prevention Devices (PSV-RW-3 and BFP-RW-11) .............. 4-34 14 4.4.6 Pressure Relief Valve (PSV-PB2-1) ...................................................... 4-39 15 4.4.7 242-A Building ...................................................................................... 4-42 16
4.5 TSR SPECIFIC ADMINISTRATIVE CONTROLS ......................................... 4-44 17 4.5.1 Flammable Gas Controls for Waste Feed Transfer Piping, Waste 18
Slurry Transfer Piping, and C-A-1 Vessel Drain (Dump) Piping .......... 4-44 19 4.5.2 Evaporator and Pump Room Access and Pump Room Cover 20
Block Control ......................................................................................... 4-48 21 4.5.3 Evaporator and Pump Room Transient Combustible Material 22
LIST OF TERMS 7 8 9 AC Administrative Control 10 ALARA as low as reasonably achievable 11 AMU aqueous makeup (room) 12 API American Petroleum Institute 13 ASCE American Society of Civil Engineers 14 ASME American Society of Mechanical Engineers 15 CFR Code of Federal Regulations 16 CGM combustible gas monitor 17 CMU concrete masonry unit 18 DOE U.S. Department of Energy 19 DSA documented safety analysis 20 DST double-shell tank 21 HVAC heating, ventilation, and air conditioning 22 IHT Industrial Hygiene Technician 23 JCI Johnson Controls Industries 24 LCO limiting condition for operation 25 LFL lower flammability limit 26 M&TE measuring and test equipment 27 MCS monitoring and control system 28 N/A not applicable 29 PAC Protective Action Criteria 30 PC performance criteria 31 RTD resistance temperature detector 32 SAC specific administrative controls 33 SIL safety integrity level 34 SIS safety instrumented system 35 SpG specific gravity 36 SSC structures, systems, and components 37 TEDF Treated Effluent Disposal Facility 38 TOC Tank Operations Contractor 39 TSR technical safety requirement 40
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4.0 SAFETY STRUCTURES, SYSTEMS, AND COMPONENTS 1 2 3 4.1 INTRODUCTION 4 5 This chapter provides details on those 242-A Evaporator structures, systems, and components 6 (SSC) and specific administrative controls (SAC) that are required to (1) prevent or mitigate 7 radioactive or hazardous material exposure to the public or onsite worker, (2) protect facility 8 workers from significant hazards, or (3) provide an important contribution to defense-in-depth. 9 (See Section 3.3.1, “Methodology,” for nuclear safety control selection and classification 10 methodology and criteria.) The determination of which SSCs and administrative controls protect 11 the public, onsite workers, facility workers, or provide an important contribution to 12 defense-in-depth is documented in Chapter 3.0, “Hazard and Accident Analyses.” 13 14 The scope of this chapter includes the following for safety SSCs. 15 16
• Descriptions of safety SSCs, including safety function(s), the basic principles by which 17 they perform their safety function(s), their boundaries, and required support systems. 18
19 • System evaluations of safety SSCs that identify the functional/performance requirements 20
necessary for the SSCs to perform their safety function(s). The evaluations also identify 21 and evaluate potential failure modes of the safety SSCs considering the conditions and 22 events in which the safety function(s) must be met. Potential failure modes considered in 23 the evaluations include: 24
- Process conditions including normal, off-normal, and accident conditions 29 30
- Environmental conditions including climatic conditions and postulated accident 31 environments 32
33 - Other failure modes 34
35 - General aging (i.e., design or service life). 36
37 In addition, the evaluations identify and evaluate interfaces whose failure could prevent 38 the SSCs from performing their safety function(s). The system evaluation satisfies 39 U.S. Department of Energy (DOE) and Tank Operations Contractor (TOC) requirements 40 to ensure the reliable performance of safety-significant SSCs to meet the safety 41 function(s) determined from the hazard and accident analyses. 42
43 • Identification of technical safety requirement (TSR) controls to ensure performance of 44
the safety function(s). 45 46
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The scope of this chapter includes the following for SACs: 1 2
• Descriptions of SACs, including safety function(s), the basic principles by which they 3 perform their safety function(s), their boundaries, and interface points with SSCs relevant 4 to the safety function(s). 5
6 • Evaluations of the SACs that identify the functional/performance requirements that are 7
necessary for the SACs to perform their safety function(s). In addition, the evaluation 8 considers human performance factors to provide assurance that operators can adequately 9 perform their required tasks, including: 10
11 - The adequacy of the description of the task in facility procedures 12 - The level of difficulty of the task 13 - The design of the equipment and feedback, e.g., indicators and alarms 14 - The time available to do the task or recover from an error 15 - The stress levels induced by the external environment, e.g., noise, heat, light, and 16
protective clothing worn. 17 18
• Identification of TSR controls to ensure performance of the safety function(s). 19 20 Note: The figures provided in this chapter have been included to aid the reader in visualizing 21
information that is presented in the text. These sketches should not be considered design 22 drawings, and they must not be used to make engineering modifications to any SSCs 23 depicted. Facility modifications are approved in accordance with detailed design 24 information found in established procedures, configuration-controlled drawings, and 25 vendor information. 26
27 28 4.2 REQUIREMENTS 29 30 Standards, regulations, and DOE Orders required for establishing the facility safety basis specific 31 to this chapter and pertinent to the safety analysis include the following: 32 33
• Title 10, Code of Federal Regulations, Part 830 (10 CFR 830), “Nuclear Safety 34 Management” 35
36 • DOE G 421.1-2, Implementation Guide for Use in Developing Documented Safety 37
Analyses to Meet Subpart B of 10 CFR 830 38 39
• DOE-STD-1186-2004, Specific Administrative Controls 40 41
• DOE-STD-3009-94, Preparation Guide for U.S. Department of Energy Nonreactor 42 Nuclear Facility Documented Safety Analyses 43
44
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Where applicable, specific design codes, standards, and regulations for a safety SSC that relate 1 directly to the safety function of that safety SSC have been identified and are provided in the 2 respective system description section in this chapter. 3 4 5 4.3 SAFETY-CLASS STRUCTURES, SYSTEMS, AND COMPONENTS 6 7 There are no safety-class SSCs identified for the 242-A Evaporator in this documented safety 8 analysis (DSA). 9 10 11 4.4 SAFETY-SIGNIFICANT STRUCTURES, SYSTEMS, AND 12
COMPONENTS 13 14 15 4.4.1 C-A-1 Vessel Flammable Gas Control System 16 17 The C-A-1 vessel flammable gas control system is identified as a safety-significant SSC for 18 flammable gas accidents (Section 3.3.2.4.1). 19 20 4.4.1.1 Safety Function(s). The safety functions of the C-A-1 vessel flammable gas control 21 system are: 22 23
1. To ensure C-A-1 vessel vacuum or purge air flow is maintained when the C-A-1 vessel 24 contains waste. Maintaining C-A-1 vessel vacuum or purge air flow when the C-A-1 25 vessel contains waste prevents a flammable gas accident in the C-A-1 vessel. 26
27 2. To limit the waste temperature in the C-A-1 vessel. Limiting the waste temperature in 28
the C-A-1 vessel protects the action completion times in the Limiting Condition for 29 Operation (LCO) for the C-A-1 vessel flammable gas control system. 30
31 4.4.1.2 System Description. The C-A-1 vessel flammable gas control system is a safety 32 instrumented system (SIS) and includes instruments (sensors), logic solvers, and final control 33 elements. The system is shown in Figure 4.4.1-1. 34 35 The C-A-1 vessel flammable gas control system monitors pressure (vacuum) in the C-A-1 vessel, 36 purge air flow to the C-A-1 vessel, and waste temperature in the C-A-1 vessel. The system 37 monitors the C-A-1 vessel pressure (vacuum) at air sensing line ½”I-CA1-3-M31, which 38 connects to the C-A-1 vessel below the lower de-entrainment pad. The system monitors the flow 39 rate of purge air to the C-A-1 vessel, which is provided by the instrument air system, on purge 40 air/raw water line ½”IA-CA1-9-M31/1”FRW-668-M9, which connects to the C-A-1 vessel 41 below the lower de-entrainment pad. The system monitors C-A-1 vessel waste temperature 42 using resistance temperature detector (RTD) elements, which are located in a thermo well on the 43 recirculation line. 44 45
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The system uses non-software programmable logic solver devices (flow switches, safety trip 1 alarms, safety relays, and time delay relays). 2 3 On high C-A-1 vessel pressure (loss of vacuum) AND low C-A-1 vessel purge air flow, OR high 4 waste temperature, the C-A-1 vessel flammable gas control system stops steam flow to the E-A-1 5 reboiler by closing steam isolation valve HV-EA1-5; stops feed pump 241-AW-P-102-1 and 6 recirculation pump P-B-1; and drains the waste from the C-A-1 vessel via two drain paths. One 7 C-A-1 vessel waste drain path is through the 3-inch feed valve HV-CA1-1 in the feed line from 8 double-shell tank (DST) 241-AW-102. The waste drains through feed pump 241-AW-P-102-1 9 to DST 241-AW-102. Valve AW02E-WT-V-107 is maintained in the 180 degree position to 10 allow backflow of waste to feed pump 241-AW-P-102-1. Opening feed valve HV-CA1-1 and 11 stopping feed pump 241-AW-P-102-1 allows waste to drain back to DST 241-AW-102 through 12 the feed line in about 2 hours, but leaves approximately 2,700 gallons of residual waste in the 13 C-A-1 vessel. Closing steam isolation valve HV-EA1-5 (i.e., stopping steam to the E-A-1 14 reboiler) and stopping recirculation pump P-B-1 limits heat input and the temperature of the 15 residual waste left in the C-A-1 vessel. The other C-A-1 vessel waste drain path is through the 16 6-inch dump valves HV-CA1-7 and HV-CA1-9 in the drain (dump) line to DST 241-AW-102. 17 Opening dump valves HV-CA1-7 and HV-CA1-9 completely empties the C-A-1 vessel in about 18 10 minutes, and eliminates the flammable gas hazard. 19 20 To prevent unnecessary actuation of the C-A-1 vessel flammable gas control system 21 (i.e., draining of the C-A-1 vessel), a 30-minute timer is provided on high vessel pressure (loss of 22 vacuum), a 30-minute timer is provided on low purge air flow rate, and a 5-second timer is 23 provided on high waste temperature. A 30-minute timer is also provided to delay draining 24 through dump valves HV-CA1-7 and HV-CA1-9 to allow time to restore C-A-1 vessel vacuum 25 or purge air flow prior to this emergency dump. 26 27 The C-A-1 vessel flammable gas control system provides C-A-1 vessel pressure and waste 28 temperature data to the general service monitoring and control system (MCS) with signal 29 isolation. Interlock status signals are also provided to the MCS with signal isolation. 30 31 The C-A-1 vessel flammable gas control system is installed in the 242-A Building. 32 33 RPP-RPT-54583, Design Analysis Report for the 242-A Evaporator C-A-1 Vessel Flammable 34 Gas Control System, provides additional description of the C-A-1 vessel flammable gas control 35 system. 36 37 Boundaries. The boundary of the safety-significant C-A-1 vessel flammable gas control system 38 consists of the following: 39 40
• Pressure transmitters PT-CA1-12 and PT-CA1-13. 41 42
• Flow switches FSH/FSLL-CA1-20A and FSH/FSLL-CA1-20B. 43 44
• Temperature elements TE-EA1-1 and TE-EA1-1S. 45 46
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• Purge air / raw water line 1”FRW-668-M9 (SS between raw water isolation valve 5-77B 1 and C-A-1 vessel). 2
3 • Purge air line ½” IA-CA1-9-M31 (SS between flow switch FSH/FSLL-CA1-20A and 4
raw water line 1” FRW-668-M9). 5 6
• Purge air isolation valves 5-3F and HV-CA1-21 and raw water isolation valve 5-77B. 7 8
• Logic solver devices located in enclosure CA1-ENCL-205 including safety relays 9 K3 – K10 and K12A, K12B, K12C, K13A, K13B, K13C, K14, and K15; time-delay 10 relays TDR3 – TDR4 and TDR6 – TDR8; safety trip alarms (STA’s include 11 YYC-EA1-1, YYC-EA1-1S, YYC-CA1-12, and YYC-CA1-13); control (switching) 12 wires; and associated terminal connections. 13
14 • Devices located in enclosure CA1-ENCL-206 including safety relays K1A, K1B, and 15
K1C; control (switching) wires; and associated terminal connections. 16 17
• Devices located in enclosure CA1-ENCL-207 including recirculation pump contactor 18 M-PB-1A, pilot relay K1-PB-1A, control (switching) wire, and associated terminal 19 connections. 20
21 • Devices located in enclosure CA1-ENCL-208 including feed pump contactor 22
M-PAW-102A, pilot relay K1-PAW-102A, control (switching) wire, and associated 23 terminal connections. 24
25 • Devices located in flow switch test boxes CA1-JBX-20A and CA1-JBX-20B including 26
control (switching) wires and associated terminal connections. 27 28
• Dump valve solenoids HY-CA1-1A, HY-CA1-7A and HY-CA1-9A. 29 30
• Dump valve assemblies HV-CA1-1 (including flow control valves FCV-CA1-1 and 31 FCV-CA1-2), HV-CA1-7, and HV-CA1-9. 32
33 • Instrument air line accumulators 242AE1-IA-ACC-001 and 242AE1-IA-ACC-002. 34
35 • Steam valve solenoid HY-EA1-5. 36
37 • Steam valve assembly HV-EA1-5. 38
39 • Solenoid general purpose air filters FG-CA1-1, FG-CA1-7/9 and FG-EA1-5. 40
41 • The control (switching) wires between flow switches FSH/FSLL-CA1-20A and 42
FSH/FSLL-CA1-20B and logic solver CA1-ENCL-205 (and test boxes CA1-JBX-20A, 43 and CA1-JBX-20B) and the control (switching) wires between logic solver 44 CA1-ENCL-205 and enclosure CA1-ENCL-206. The control (switching) wire from 45
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enclosure CA1-ENCL-206 to valve solenoids HY-CA1-1A, HY-CA1-7A, HY-CA1-9A, 1 and HY-EA1-5. The control (switching) wire from enclosure CA1-ENCL-206 to 2 enclosures CA1-ENCL-207 and CA1-ENCL-208. 3
4 • Enclosures CA1-ENCL-205, CA1-ENCL-206, CA1-ENCL-207, and CA1-ENCL-208. 5
6 Note: The pressure sensing line that is connected to the C-A-1 vessel is not included in the 7
boundary because a loss of pressure sensing line integrity will cause a reduction in the 8 measured vacuum, which is conservative. 9
10 Support Systems. The 242-A Building is required to protect the C-A-1 vessel flammable gas 11 control system from damage due to ash, snow, and wind loads and, therefore, is designated 12 safety-significant (see Section 4.4.7). 13 14 4.4.1.3 Functional Requirements. The functional requirement for the C-A-1 vessel flammable 15 gas control system is to monitor C-A-1 vessel pressure (vacuum), purge air flow, and waste 16 temperature; and on high C-A-1 vessel pressure (loss of vacuum) (> 200 Torr) AND low C-A-1 17 vessel purge air flow (< 3.0 standard ft3/min), OR high waste temperature (> 160°F): 18 19
• Stop feed pump 241-AW-P-102-1 20 • Open feed valve HV-CA1-1 to drain the C-A-1 vessel 21 • Close steam isolation valve HV-EA1-5 22 • Stop recirculation pump P-B-1 23 • After a time delay, open dump valves HV-CA1-7 and HV-CA1-9 to empty the C-A-1 24
vessel if the trip condition is still present. 25 26 The initial actions prevent a flammable gas accident by draining the vessel via the feed line and 27 limiting the temperature of the residual waste. The additional action of opening dump valves 28 HV-CA1-7 and HV-CA1-9 is a redundant method of preventing a flammable gas accident by 29 emptying the C-A-1 vessel. 30 31 In accordance with the methodology for safety integrity level (SIL) determination for SIS 32 described in Section 3.3.1.5, the required safety integrity level is SIL-2. The basis for SIL-2 is 33 described in RPP-RPT-54583 and is based on the consequences of a flammable gas accident in 34 the C-A-1 vessel exceeding Protective Action Criteria (PAC)-3 onsite and the assigned 35 frequency being “anticipated.” 36 37 There are no other functional/performance requirements derived from the hazard and accident 38 analyses, but additional requirements necessary to satisfy the safety function are developed in the 39 system evaluation (see Section 4.4.1.4). 40 41 4.4.1.4 System Evaluation. The system evaluation of the C-A-1 vessel flammable gas control 42 system is documented in RPP-RPT-54583. The evaluation identifies the functional/performance 43 requirements necessary for the C-A-1 vessel flammable gas control system to perform its safety 44 functions. The evaluation also identifies and evaluates potential failure modes of the C-A-1 45 vessel flammable gas control system considering the conditions and events in which the safety 46
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functions must be met. In addition, the evaluation identifies and evaluates support systems 1 whose function is required for the C-A-1 vessel flammable gas control system to perform its 2 safety functions and interfaces whose failure could prevent the C-A-1 vessel flammable gas 3 control system from performing its safety functions. The evaluation results are summarized in 4 Table 4.4.1-1. The system evaluation satisfies DOE and TOC requirements to ensure the reliable 5 performance of safety-significant SSCs to meet the safety function(s) determined from the 6 hazard and accident analyses. 7 8 The primary functional/performance requirement is to drain or empty waste from the C-A-1 9 vessel, stop steam to the E-A-1 reboiler (i.e., close steam isolation valve HV-EA1-5), and stop 10 recirculation pump P-B-1 if pressure (vacuum) in the C-A-1 vessel headspace is > 200 Torr and 11 purge air flow to the C-A-1 vessel is < 3.0 standard ft3/min, or if the C-A-1 vessel waste 12 temperature is > 160°F. This function must meet SIL-2 requirements for this SIS. This 13 requirement is met by system design, selection of components, and by performing periodic 14 calibrations, calibration checks, and functional tests. The system design provides redundant 15 vessel pressure (vacuum) instrumentation, redundant purge air flow instrumentation, redundant 16 waste temperature instrumentation, redundant logic solver devices, and redundant means to drain 17 waste from the vessel. 18 19 The requirement to stop steam flow to the E-A-1 reboiler (i.e., close steam isolation valve 20 HV-EA1-5) and to stop feed pump 241-AW-P-102-1 and recirculation pump P-B-1 is only related 21 to draining waste through feed valve HV-CA1-1 (stopping feed pump 241-AW-P-102-1 allows 22 waste to drain back to DST 241-AW-102 through the feed line; stopping steam to the E-A-1 23 reboiler and stopping recirculation pump P-B-1 limits heat input to the residual waste left when 24 draining through feed valve HV-CA1-1, thus limiting the flammable gas generation rate). 25 Draining the vessel through feed valve HV-CA1-1 leaves approximately 2,700 gallon of residual 26 waste in the C-A-1 vessel. Analysis in RPP-CALC-29700, Flammability Analysis and Time to 27 Reach Lower Flammability Limit Calculations for the 242-A Evaporator, shows that with 28 2,700 gallons of residual waste in the C-A-1 vessel at the maximum waste temperature of 160°F, it 29 takes several months to reach 100% of the LFL assuming either zero ventilation or barometric 30 breathing. Because during this time the residual waste will cool, the RPP-CALC-29700 analysis 31 also shows that at a residual waste temperature of 90oF (reasonably conservative ambient 32 temperature), it takes years to reach 100% of the LFL conservatively assuming zero ventilation, 33 and that barometric breathing is sufficient to prevent reaching 100% of the LFL. Because several 34 different actions can be readily implemented to ensure barometric breathing of the C-A-1 vessel 35 (e.g., operate the vessel ventilation system, provide purge air flow, open a ventilation path to the 36 C-A-1 vessel), the 2,700 gallons of residual waste in the C-A-1 vessel is not a flammable gas 37 hazard (i.e., the flammable gas concentration in the C-A-1 vessel will not reach 100% of the LFL). 38 39 The C-A-1 vessel flammable gas control system is located in the 242-A Building and is designed 40 for applicable process conditions (exposure to waste, steam, instrument air, and/or C-A-1 vessel 41 vacuum) and environmental conditions, which results in requirements on design pressure, design 42 temperature, and material compatibility, as well as protection from exposure to air compressor 43 oil, ash, and dust. 44 45
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Trip Limits and Time Delays. The C-A-1 vessel flammable gas control system trip limits are 1 derived in RPP-TE-53945, Technical Basis for 242-A Safety Instrumented Systems Sensing 2 Parameters and Timers. When the C-A-1 vessel headspace pressure is ≤ 200 Torr, the headspace 3 of the C-A-1 vessel is primarily water vapor and air has been evacuated from the system, thus 4 preventing a flammable gas accident. The minimum purge air flow rate is that required to limit 5 the flammable gas concentration in the C-A-1 vessel headspace to ≤ 25% of the LFL assuming a 6 reasonably conservative C-A-1 vessel waste fill volume of 26,000 gallons, waste temperature of 7 160°F, and waste specific gravity (SpG) of 1.6. In addition, the analysis assumes the addition of 8 three drums of antifoam prior to waste concentration. The analysis results in RPP-CALC-29700 9 show a purge rate of < 3.0 actual ft3/min conservatively bounds the supernatant waste in all of the 10 DSTs. (Note: The bounding waste supernatants, those in 241-AN-102 and 241-AN-107, are 11 already concentrated and are not planned for 242-A Evaporator feed.) The trip limit is established 12 at 3.0 standard ft3/min, which is conservative relative to the analysis limit of 3.0 actual ft3/min at 13 elevated C-A-1 vessel headspace temperatures (e.g., 160°F). To address potential failure modes 14 of the purge air flow switches (i.e., flow switch detected device failures can cause high purge air 15 flow indication), there is also a high purge air flow trip (fault detection). 16 17 To prevent unnecessary actuation of the C-A-1 vessel flammable gas control system (i.e., draining 18 of the C-A-1 vessel), a 30-minute timer is provided on high vessel pressure (loss of vacuum), a 19 30-minute timer is provided on low (or high) purge air flow rate, and a 5-second timer is provided 20 on high waste temperature. A 30-minute timer is also provided to delay draining through dump 21 valves HV-CA1-7 and HV-CA1-9 to allow time to restore C-A-1 vessel vacuum or purge air flow 22 prior to this emergency dump. These time delays are supported by analysis in RPP-CALC-29700. 23 Assuming that the C-A-1 vessel flammable gas control system fails to drain through feed valve 24 HV-CA1-1, close steam isolation valve HV-EA1-5, or to shut off recirculation pump P-B-1 25 (failure of one drain path), emptying the C-A-1 vessel through dump valves HV-CA1-7 and 26 HV-CA1-9, starting 30 minutes following trip on high waste temperature, removes the hazard 27 prior to the flammable gas concentration in the C-A-1 vessel reaching 25% of the LFL. This is 28 shown in RPP-CALC-29700 conservatively assuming the waste heats to 230°F in the 30 minutes 29 between C-A-1 vessel flammable gas control system trip at 160°F and opening dump valves 30 HV-CA1-7 and HV-CA1-9. 31 32 The C-A-1 vessel flammable gas control system setpoints and time delays are based on maintaining 33 the flammable gas concentration in the C-A-1 vessel < 25% of the LFL. This control point of ≤ 25% 34 of the LFL establishes a margin of safety and is based on National Fire Protection Association 35 (NFPA) standards. Specifically, NFPA 69, Standard on Explosion Prevention Systems, states that, 36 relative to the design and operational requirements of systems used for combustion concentration 37 reduction, the combustible concentration shall be maintained at or below 25% of the LFL. 38 39 4.4.1.4.1 Failure Mode Evaluation. RPP-RPT-54583 reviewed and evaluated the C-A-1 vessel 40 flammable gas control system for compliance with SIL-2 requirements as well as potential 41 failure modes that could impact the ability to meet the safety functions. The evaluation results in 42 the following design requirements for the C-A-1 vessel flammable gas control system. 43 44
• The C-A-1 vessel flammable gas control system shall fail-safe upon a loss of power to 45 the system or any individual system component. 46
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1 • The C-A-1 vessel flammable gas control system shall fail-safe upon a loss of 2
communication from any or all instrumentation to the logic solver devices. 3 4
• The C-A-1 vessel flammable gas control system shall fail-safe upon a loss of air supply 5 to the valves (i.e., HV-CA1-1, HV-CA1-7, and HV-CA1-9 shall fail open; HV-EA1-5 6 shall fail closed). 7
8 • The C-A-1 vessel flammable gas control system shall fail-safe upon a loss of control 9
voltage from the logic solver devices to the feed pump 241-AW-P-102-1 and recirculation 10 pump P-B-1 contactors and upon a loss of control voltage from the logic solver devices to 11 the HV-CA1-1, HV-CA1-7, HV-CA1-9, and/or HV-EA1-5 valve solenoids. 12
13 • The C-A-1 vessel flammable gas control system shall fail-safe when a detected device 14
failure occurs. (Note: Flow switches FSH/FSLL-CA1-20A and FSH/FSLL-CA1-20B 15 output a high or low purge air flow indication for detected failures, which opens the 16 associated safety relay. The pressure safety trip alarms [YYC-CA1-12 and YYC-CA1-13] 17 and waste temperature [RTD] safety trip alarms [YYC-EA1-1 and YYC-EA1-1S] output 18 fault detection signals, which trip an associated fault detection safety relay.) 19
20 • The C-A-1 vessel flammable gas control system shall fail-safe when an RTD element 21
short or open circuit has occurred. 22 23
• The pressure transmitters shall be installed above the sensing and purge air lines. 24 Plugged pressure sensing elements are an unsafe failure that could result in inaccurate 25 (non-conservative) data being transmitted to the logic solvers. (Note: An unsafe failure 26 is a failure that could prevent the C-A-1 vessel flammable gas control system from 27 performing its safety function.) Plugging may be a result of dirty or humid air supply or 28 waste migration to the sensor. Installing the transmitters above the sensing and purge air 29 lines reduces the likelihood of plugging. 30
31 • The RTD elements shall be made of platinum and shall have stainless-steel sheathing. 32
The RTDs will be used under continuous operation and be subject to high temperatures. 33 Platinum RTDs have acceptable aging characteristics. Selection of stainless-steel-34 sheathed RTDs protects the materials from damage from the process fluids (waste). 35
36 • The RTDs shall be a three- or four-wire RTD and shall be grounded and shielded. The 37
RTDs require appropriate grounding and the use of a reference wire in the external circuitry. 38 Failures of the ground or shield can lead to intermittent interference from external circuit 39 operations and inaccurate (non-conservative) temperature measurement data. 40
41 • The control (switching) wires between flow switches FSH/FSLL-CA1-20A and 42
FSH/FSLL-CA1-20B and enclosure CA1-ENCL-205; the control (switching) wires 43 between flow switches FSH/FSLL-CA1-20A and FSH/FSLL-CA1-20B and flow switch 44 test boxes CA1-JBX-20A and CA1-JBX-20B; the control (switching) wires between 45 enclosures CA1-ENCL-205 and CA1-ENCL-206; the control (switching) wires from 46
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enclosure CA1-ENCL-206 to valve solenoids HY-CA1-1A, HY-CA1-7A, HY-CA1-9A, 1 and HY-EA1-5; and the control (switching) wires from enclosure CA1-ENCL-206 to 2 enclosure CA1-ENCL-207 and enclosure CA1-ENCL-208, shall be properly insulated for 3 the electrical and environment conditions. These control wires are required to be 4 insulated to prevent a short resulting in the interlock not performing its safety function 5 (i.e., short to power). 6
7 • The control (switching) wires and associated terminal connections (i.e., terminal blocks) 8
located inside enclosures CA1-ENCL-205, CA1-ENCL-206, CA1-ENCL-207, and 9 CA1-ENCL-208, and inside flow switch test boxes CA1-JBX-20A and CA1-JBX-20B, 10 shall be properly insulated for the electrical and environment conditions. These control 11 wires and terminal blocks are required to be insulated to prevent a short resulting in the 12 interlock not performing its safety function (i.e., short to power). 13
14 • Enclosures CA1-ENCL-205, CA1-ENCL-206, CA1-ENCL-207, and CA1-ENCL-208 15
shall protect the contained components from failure due to ash and dust. 16 17
• The C-A-1 vessel flammable gas control system shall be isolated from the MCS using 18 isolation devices or devices that include signal isolation. 19
20 • The purge air line ½”IA-CA1-9-M31 (between the flow switches and the connection to 21
the purge air/raw water line 1”FRW-668-M9) including valves HV-CA1-21 and 5-3F and 22 the purge air/raw water line 1”FRW-668-M9 (between raw water isolation valve 5-77B 23 and C-A-1 vessel) including valve 5-77B, originally designed and installed in accordance 24 with ASME B31.1-1973, Power Piping, have been evaluated for equivalency with 25 ASME B31.3, Process Piping (see RPP-TE-55027, 242-A Safety Significant Process 26 Piping Equivalency B31.1-1973/2004 to B31.3-2012). Future modifications to these lines 27 shall be designed and installed in accordance with American Petroleum Institute (API) 28 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of 29 Piping Systems. Leakage or rupture of the purge air line/raw water line between the flow 30 switches and the C-A-1 vessel is an unsafe failure mode (measured purge air flow may 31 not reach the vessel). 32
33 • The safety-significant solenoid valves for valves HV-CA1-1, HV-CA1-7, and HV-CA1-9 34
shall be installed downstream of the general service solenoid valve and nearest to the 35 associated valve actuator. The safety-significant solenoid valve for valve HV-EA1-5 36 shall be installed in the AMU Room near the wall penetration for the air line to the 37 outside valve actuator. Installing the safety-significant solenoid valves nearest to valve 38 actuator and downstream of the general service components prevents failures of the 39 general service components from affecting the safety-significant solenoid valves from 40 performing their safety function. 41
42 • Safety-significant air filters shall be installed upstream of the solenoid valves for valves 43
HV-CA1-1, HV-CA1-7, HV-CA1-9, and HV-EA1-5. These general purpose particulate 44 air filters shall be rated for a maximum particle size of 50 microns or smaller. The filters 45 prevent failure due to plugging as a result of dirty or moist compressed air. 46
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1 • The safety-significant 242-A Building is identified as a supporting SSC. It is designed to 2
not fail due to ash, snow, and wind loads, and thus protect the C-A-1 vessel flammable 3 gas control system from damage due to these loads. 4
5 • The C-A-1 vessel flammable gas control system shall fail safe (i.e., prevent a flammable 6
gas accident in the C-A-1 vessel) in the event of a facility fire. SAC Evaporator and 7 Pump Room Combustible Material Controls prevents unsafe failures of feed valve 8 HV-CA1-1 and dump valves HV-CA1-7 and HV-CA1-9 due to fires (see Section 4.5.3). 9 Because the C-A-1 vessel flammable gas control system may not fail safe from 10 postulated fires in other areas of the facility, there is a planned design improvement to 11 ensure the C-A-1 vessel flammable gas control system fails safe in the event of a facility 12 fire (see Section 3.3.2.3.5). Until the planned design improvement is completed, AC 13 Emergency Response Actions Following Facility Fires is required to address facility fires 14 that could prevent the C-A-1 vessel flammable gas control system from performing its 15 safety functions (see Section 5.5.3.9). 16
17 • The C-A-1 vessel flammable gas control system is not required to perform its safety function 18
during or after a seismic event (see Section 4.4.3, “C-A-1 Vessel Seismic Dump System”). 19 20
• Damage to the C-A-1 vessel flammable gas control system from readily detected events 21 (i.e., load handling accidents) when there is waste in the C-A-1 vessel (i.e., in the 22 Operation Mode - see Section 5.4.1 for mode descriptions) will result in prompt 23 shutdown of the 242-A Evaporator and removal of the waste from the C-A-1 vessel if the 24 damage is determined to be significant enough to prevent the C-A-1 vessel flammable 25 gas control system from performing its safety function. (Note: There is also a 26 defense-in-depth feature to address this initiator. That is, the hoisting and rigging 27 program to prevent load handling accidents.) 28
29 • Damage to the C-A-1 vessel flammable gas control system from readily detected events 30
(i.e., seismic events, load handling accidents, and fires) when there is limited or no waste 31 in the C-A-1 vessel (i.e., in the Limited Waste Mode or Shutdown Mode) will result in an 32 inspection and the necessary testing/repair/replacement prior to returning the C-A-1 33 vessel flammable gas control system to service. (Note: There are also defense-in-depth 34 features to address these initiators. That is, the emergency preparedness program for 35 seismic events, the hoisting and rigging program to prevent load handling accidents, and 36 fire protection requirements to address fires.) 37
38 • The instrument air line (3/4” IA-735-M7) that supplies air to the steam isolation valve 39
HV-EA1-5 actuator shall include safety-significant airline accumulators 242AE1-IA-ACC-001 40 and 242AE1-IA-ACC-002 upstream sized for a minimum of one complete actuator air 41 exchange to ensure the air is supplied to the solenoid valve and steam valve actuator is within 42 the temperature ratings of the components. 43
44
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• The instrument air line (3/4” IA-735-M7) that supplies air to the steam isolation value 1 HV-EA1-5 actuator shall be sloped outside the facility. Each low point location shall 2 include a drain value for periodic blowdown of line to prevent the air line from becoming 3 plugged with condensation. 4
5 Based on design life and operating conditions, the ability of the C-A-1 vessel flammable gas 6 control system to perform its safety function can degrade and periodic calibrations, calibration 7 checks, and functional tests are required. The calibration, calibration check, and functional test 8 frequencies are established in the SIL calculation (RPP-CALC-54585, SIL Verification 9 Calculation for 242-A Evaporator C-A-1 Vessel Flammable Gas Control System) to ensure that 10 C-A-1 vessel flammable gas control system reliability meets SIL-2 requirements. 11 12 Note: The calibrations, calibration checks, and functional tests may be performed by any series 13
of sequential, overlapping, or total steps such that the system responds within the 14 required range and accuracy to known values of input and the system trip and fault 15 functions are operable. The calibrations, calibration checks, and functional tests may also 16 be accomplished, in part, by calibrations, calibration checks, and functional tests of the 17 C-A-1 vessel waste high level control system (see Section 4.4.2) and/or the C-A-1 vessel 18 seismic dump system (see Section 4.4.3) with which the C-A-1 vessel flammable gas 19 control system shares several components. 20
21 Calibrations, calibration checks, and functional testing of the C-A-1 vessel flammable gas 22 control system shall be performed at least once per six months (i.e., 182 days). 23 24 Calibration is the adjustment, as necessary, of the instrumentation such that it responds within 25 the required range and accuracy to known values of input. A calibration check is performed 26 when the instrumentation cannot be calibrated (adjusted), and includes a comparison of the 27 instrumentation with other independent instrumentation, known values, or other circuits/systems 28 monitoring the same variable. Instrumentation includes the sensor, signal conditioning elements, 29 and output devices required to meet the safety function. 30 31 The pressure (vacuum) instrumentation (pressure transmitters PT-CA1-12 and PT-CA1-13 and 32 associated safety trip alarms YYC-CA1-12 and YYC-CA1-13) and the waste temperature (RTD) 33 safety trip alarms (YYC-EA1-1 and YYC-EA1-1S) are calibrated. The purge air flow 34 instrumentation (flow switches FSH/FSLL-CA1-20A and FSH/FSLL-CA1-20B) and waste 35 temperature RTD elements (TE-EA1-1 and TE-EA1-1S) are calibration checked. The as-found 36 and as-left results of the calibrations/calibration checks are independently verified to be within a 37 specified range. The calibration/calibration check of the redundant C A-1 vessel flammable gas 38 control system instrumentation, except for the waste temperature RTD elements, is staggered in 39 time (i.e., like components are not calibrated/calibration checked at the same time). 40 41 The pressure (vacuum) instrumentation (pressure transmitters and associated safety trip alarms), 42 the waste temperature instrumentation (RTD elements and associated safety trip alarms), and the 43 purge air flow instrumentation (flow switches) shall be calibrated/calibration checked. The 44 as-found and as-left results of the calibrations/calibration checks shall be independently verified 45 to be within a specified range. The calibration/calibration check of the redundant C-A-1 vessel 46
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flammable gas control system instrumentation, except for the waste temperature RTD elements, 1 shall be performed by different personnel (i.e., like components are not calibrated/calibration 2 checked by the same person). 3 4 The functional tests of the C-A-1 vessel flammable gas control system shall include the 5 following: 6 7
• Verify the trip limits. 8 9
− 200 Torr for high pressure (loss of vacuum) trip 10 − 3.0 standard ft3/min for low purge air flow trip 11 − 160°F for waste high temperature trip 12
13 Note: The final trip setpoints shall account for instrumentation accuracy. 14
15 • Verify timer durations. 16
17 − ≤ 30 minutes for high pressure (loss of vacuum) trip 18 − ≤ 30 minutes for low and high purge air flow trip 19 − ≤ 5 seconds for waste high temperature trip 20 − ≤ 30 minutes for opening dump valves HV-CA1-7 and HV-CA1-9 21
22 • Verify with simulated or actual trip signals from each of the redundant C-A-1 vessel 23
pressure (vacuum), purge air flow, and waste temperature instrumentation (i.e., high 24 C-A-1 vessel pressure [loss of vacuum] AND low C-A-1 vessel purge air flow, OR high 25 waste temperature) that: 26
35 • Verify purge air/raw water line (½”IA-CA1-9-M31/1”FRW-668-M9) integrity between 36
the purge air flow instrumentation and C-A-1 vessel. 37 38
• Verify a clear flow path in instrument air line ¼” 1A-735-M7 by sequentially opening 39 drain valves 242AO-IA-V-005 and 242AO-IA-V-004 with air supplied to HV-EA1-5 40 allowing collected condensation and oil to be purged. 41
42 • Verify adequate closure for the steam isolation valve while steam is on and water is in the 43
C-A-1 vessel by closing HV-EA1-5 and verify the differential temperature across the 44 reboiler is less than or equal to 0.8°F. 45
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1 RPP-CALC-54585 evaluates the C-A-1 vessel flammable gas control system and demonstrates 2 compliance with SIL-2 requirements. RPP-TE-58237, Technical Basis and Parameters for 3 HV-CA1-5, Seismic Steam Shut-Off Valve, Steam Shut-off Qualification, provides details and 4 justification for the steam valve closure functional test. 5 6 4.4.1.5 Controls (TSRs). The C-A-1 vessel flammable gas control system is an SIS whose 7 characteristics are ensured through design, procurement, installation, startup testing, 8 configuration control, and quality conformance inspections. The activities performed under 9 these programs ensure that the safety functions of the C-A-1 vessel flammable gas control 10 system are preserved and protect the design baseline from inadvertent change. 11 12 The safety-significant C-A-1 vessel flammable gas control system is required to be operable in 13 the Operation Mode (see Section 5.4.1 for mode definitions). 14 15 Periodic calibrations, calibration checks, and functional tests are required to ensure the 16 operability of the C-A-1 vessel flammable gas control system by: 17 18
• Performing calibrations, calibration checks, and functional tests of the C-A-1 vessel 19 flammable gas control system. Calibration, calibration check, and functional test 20 frequencies and requirements are as described in the system evaluation. 21
22 23 4.4.2 C-A-1 Vessel Waste High Level Control System 24 25 The C-A-1 vessel waste high level control system is identified as a safety-significant SSC for 26 flammable gas accidents (Section 3.3.2.4.1) and waste leaks and misroutes (Section 3.3.2.4.3). 27 28 4.4.2.1 Safety Function(s). The safety function of the C-A-1 vessel waste high level control 29 system is to prevent the overflow, boil-over, and carry-over of waste from the C-A-1 vessel into 30 the process condensate system. Preventing the overflow of waste from the C-A-1 vessel into the 31 process condensate system prevents a flammable gas accident in process condensate tank 32 TK-C-100 due to the accumulation of flammable gas generated by waste in the tank. Preventing 33 the overflow of waste from the C-A-1 vessel into process condensate tank TK-C-100 also 34 protects facility workers from direct radiation hazards. In addition, preventing the overflow, 35 boil-over, and carry-over of waste from the C-A-1 vessel into the process condensate system 36 protects facility workers from (1) a flammable gas accident in process condensate system piping 37 and components due to the accumulation of flammable gas generated by contaminated process 38 condensate in process condensate system piping or components, and (2) chemical burn hazards 39 during process condensate sampling activities due to contaminated process condensate. 40 41 4.4.2.2 System Description. The C-A-1 vessel waste high level control system is a safety 42 instrumented system (SIS) and includes instruments (sensors), logic solvers, and final control 43 elements. The system is shown in Figure 4.4.2-1. 44
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1 The C-A-1 vessel waste high level control system monitors the differential pressure between the 2 two air sensing lines ½”I-CA1-2-M31 and ½”I-CA1-3-M31 that are located above and below the 3 lower C-A-1 vessel de-entrainment pad, respectively. The differential pressure increases when 4 the waste level increases above the lower sensing line. The differential pressure across the lower 5 de-entrainment pad also increases when the waste in the C-A-1 vessel is boiling or foaming. 6 7 The C-A-1 vessel waste high level control system uses non-software programmable logic solver 8 devices (flow switches, safety trip alarms, safety relays, and time delay relays). 9 10 On sensing a high differential pressure, the C-A-1 vessel waste high level control system opens 11 vacuum break valve HV-EC1-5, stops feed pump 241-AW-P-102-1, opens the 3-inch feed valve 12 HV-CA1-1 in the feed line from DST 241-AW-102, and, after a time delay, opens the 6-inch 13 dump valves HV CA1-7 and HV-CA1-9 in the drain (dump) line to DST 241-AW-102. Valve 14 AW02E-WT-V-107 is maintained in the 180 degree position to allow backflow of waste to feed 15 pump 241-AW-P-102-1 when feed valve HV-CA1-1 is opened. 16 17 A small air flow is required through the two air sensing lines ½”I-CA1-2-M31 and 18 ½”I-CA1-3-M31 for accurate differential pressure measurement. Therefore, the C-A-1 vessel 19 waste high level control system also monitors the air flow rate on both sensing lines to verify air 20 flow for accurate differential pressure measurement. 21 22 To prevent unnecessary actuation of the C-A-1 vessel waste high level control system (i.e., 23 breaking C-A-1 vessel vacuum, draining of the C-A-1 vessel), a 5-second timer is provided on 24 high differential pressure, a 60-second timer is provided on high air flow through air sensing line 25 ½”I-CA1-2-M31, and a 60-second timer is provided on low air flow through air sensing line 26 ½”I-CA1-3-M31. A 30-minute timer is also provided to delay draining through dump valves 27 HV-CA1-7 and HV-CA1-9 to allow time to restore the differential pressure and/or sensing line 28 air flow rates prior to this emergency dump. 29 30 The C-A-1 vessel waste high level control system also provides differential pressure data to the 31 general service MCS with signal isolation. Interlock status signals are also provided to the MCS 32 with signal isolation. 33 34 The C-A-1 vessel waste high level control system is installed in the 242-A Building. 35 36 RPP-RPT-54584, Design Analysis Report for the 242-A Evaporator C-A-1 Vessel Waste High 37 Level Control System, provides additional description of the C-A-1 vessel waste high level 38 control system. 39 40
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Boundaries. The boundary of the safety-significant C-A-1 vessel waste high level control 1 system consists of the following. 2 3
• Flow switches FSHH/FSL-CA1-8 and FSH/FSLL-CA1-9 and associated instrument air 6 sensing lines ½”I-CA1-2-M31 and ½”I-CA1-3-M31, respectively, between the flow 7 switches and the C-A-1 vessel, including valves 5-113, 5-113B, 5-113C, 5-114, and 8 5-114C; and control (switching) wires and associated terminal connections located in 9 flow switch test boxes CA1-JBX-8 and CA1-JBX-9. 10
11 • Enclosure CA1-ENCL-205 and the other contained logic solver devices including safety 12
relays, time-delay relays, control (switching) wires, and associated terminal connections. 13 14
• Enclosure CA1-ENCL-206 and the contained safety relays, control (switching) wires, and 15 associated terminal connections. 16
17 • Vacuum break valve HV-EC1-5 and associated solenoid valve HY-EC1-5; and air filter 18
FG-EC1-5. 19 20
• Enclosure CA1-ENCL-208 and the contained feed pump contactor M-PAW-102A, pilot 21 relay, control (switching) wires, and associated terminal connections. 22
23 • Feed valve HV-CA1-1 and associated flow control valves FCV-CA1-1 and FCV-CA1-2; 24
solenoid valve HY-CA1-1A; and air filter FG-CA1-1. 25 26
• Dump valves HV-CA1-7 and HV-CA1-9 and associated solenoid valves HY-CA1-7A 27 and HY-CA1-9A; and air filter FG-CA1-7/9. 28
29 • The control (switching) wires between flow switches FSHH/FSL-CA1-8 and 30
FSH/FSLL-CA1-9 and enclosure CA1-ENCL-205; the control (switching) wires between 31 flow switches FSHH/FSL-CA1-8 and FSH/FSLL-CA1-9 and flow switch test boxes 32 CA1-JBX-8 and CA1-JBX-9; the control (switching) wires between enclosure 33 CA1-ENCL-205 and enclosure CA1-ENCL-206; the control (switching) wires from 34 enclosure CA1-ENCL-206 to valve solenoids HY-CA1-1A, HY-CA1-7A, HY-CA1-9A, 35 and HY-EC1-5; and the control (switching) wires from enclosure CA1-ENCL-206 to 36 enclosure CA1-ENCL-208. 37
38 Note: Instrument air sensing lines ½”I-CA1-2-M31 and ½”I-CA1-3-M31 upstream of the flow 39
switches are not included in the boundary because a loss of sensing line integrity will 40 cause a reduction in the measured flow rate, which is conservative. 41
42 Support Systems. The 242-A Building is required to protect the C-A-1 vessel waste high level 43 control system from damage due to ash, snow, and wind loads and, therefore, is designated 44 safety significant (see Section 4.4.7). 45 46
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4.4.2.3 Functional Requirements. The functional requirement for the C-A-1 vessel waste high 1 level control system is to (1) detect C-A-1 vessel waste high level based on the differential 2 pressure across the lower de-entrainment pad, and (2) on high level (i.e., high differential 3 pressure across the lower de-entrainment pad): 4 5
• Open vacuum break valve HV-EC1-5. 6 • Stop feed pump 241-AW-P-102-1. 7 • Open feed valve HV-CA1-1 to drain the C-A-1 vessel. 8 • After a time delay, open dump valves HV-CA1-7 and HV-CA1-9 to empty the C-A-1 9
vessel if the trip condition is still present. 10 11 Opening vacuum break valve HV-EC1-5 stops boiling in the C-A-1 vessel, preventing boil-over 12 caused by sudden increased vacuum, and carry-over caused by foaming. (Note: Previous 13 experience with boiling liquid/foam events indicates that opening the vacuum break valve within 14 a few minutes is adequate to prevent a waste overflow event from occurring.) Stopping feed 15 pump 241-AW-P-102-1, opening feed valve HV-CA1-1, and opening dump valves HV-CA1-7 16 and HV-CA1-9 after a time delay prevents the overflow of waste from the C-A-1 vessel into the 17 process condensate system. 18 19 In accordance with the methodology for safety integrity level (SIL) determination for SIS 20 described in Section 3.3.1.5, the required safety integrity level is SIL-1. The basis for SIL-1 is 21 described in RPP-RPT-54584 and is based on the frequency of a flammable gas accident in 22 TK-C-100 being “extremely unlikely,” and there being other additional measures to protect the 23 facility worker from a flammable gas accident in process condensate system piping and 24 components; and from the direct radiation hazards and chemical burn hazards of waste in process 25 condensate tank TK-C-100 and other process condensate piping, systems, and components. 26 27 There are no other functional/performance requirements derived from the hazard and accident 28 analyses, but additional requirements necessary to satisfy the safety function are developed in the 29 system evaluation (see Section 4.4.2.4). 30 31 4.4.2.4 System Evaluation. The system evaluation of the C-A-1 vessel waste high level control 32 system is documented in RPP-RPT-54584. The evaluation identifies the functional/performance 33 requirements necessary for the C-A-1 vessel waste high level control system to perform its safety 34 function. The evaluation also identifies and evaluates potential failure modes of the C-A-1 35 vessel waste high level control system considering the conditions and events in which the safety 36 function must be met. In addition, the evaluation identifies and evaluates support systems whose 37 function is required for the C-A-1 vessel waste high level control system to perform its safety 38 function and interfaces whose failure could prevent the C-A-1 vessel waste high level control 39 system from performing its safety function. The evaluation results are summarized in 40 Table 4.4.2-1. The system evaluation satisfies DOE and TOC requirements to ensure the reliable 41 performance of safety-significant SSCs to meet the safety function(s) determined from the 42 hazard and accident analyses. 43 44
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The primary functional/performance requirement is to detect C-A-1 vessel waste high level 1 based on the differential pressure across the lower de-entrainment pad and on high level (high 2 differential pressure) to (1) open vacuum break valve HV-EC1-5, (2) stop feed pump 3 241-AW-P-102-1, (3) open feed valve HV-CA1-1, and (4) after a time delay, open dump valves 4 HV-CA1-7 and HV-CA1-9 to empty the C-A-1 vessel. This function must meet SIL-1 5 requirements for this SIS. This requirement is met by system design, selection of components, 6 and by performing periodic calibrations, calibration checks, and functional tests. 7 8 The C-A-1 vessel waste high level control system is located in the 242-A Building and is 9 designed for applicable process conditions (exposure to waste and/or instrument air) and 10 environmental conditions, which results in requirements on design pressure, design temperature, 11 and material compatibility, as well as protection from exposure to air compressor oil, ash, and 12 dust. 13 14 Trip limits and time delays. The C-A-1 vessel waste high level control system trip limits and 15 time delays are derived in RPP-TE-53945. The high level (high differential pressure) trip limit is 16 8 in. w.g. differential. This trip limit is above the general service transmitter setpoint such that 17 the general service transmitter and MCS may control the event before challenging the C-A-1 18 vessel waste high level control system, but provides a trip prior to the waste level reaching the 19 de-entrainment pad. To prevent unnecessary actuation of the C-A-1 vessel waste high level 20 control system (i.e., breaking C-A-1 vessel vacuum, draining of the C-A-1 vessel), a 5 second 21 time delay is provided to delay tripping on high differential pressure. 22 23 The instrument flow rate to the waste high level sensing lines is typically set to 24 1.0 - 1.5 standard ft3/hr, as measured by local rotameters on the supply side of each instrument 25 air line. The high flow trip limit for flow switch FSHH/FSL-CA1-8 (on ½”I-CA1-2-M31, which 26 is above the lower de-entrainer) is 3.0 standard ft3/hr. The low flow trip limit for flow switch 27 FSH/FSLL-CA1-9 (on ½”I-CA1-3-M31, which is below the lower de-entrainer) is 28 0.75 standard ft3/hr. These trip limits provide adequate accuracy for waste high level detection 29 while providing margin to the typical operating flow rate. To address potential failure modes of 30 the flow switches (i.e., flow switch detected device failures can cause high or low flow 31 indication), there is also a low flow trip (fault detection) for flow switch FSHH/FSL-CA1-8, and 32 a high flow trip (fault detection) for flow switch FSH/FSLL-CA1-9. To prevent unnecessary 33 actuation of the C-A-1 vessel waste high level control system, a 60-second timer is provided to 34 delay tripping on high or low sensing line air flow rate. Sixty seconds is well below the time that 35 has historically been associated with a boil-over or foam-over event. 36 37 To prevent unnecessary emergency dumps, a 30-minute timer is provided to allow restoration of 38 waste level before opening dump valves HV-CA1-7 and HV-CA1-9. Thirty minutes is less than 39 the 40 minutes required for waste to reach the vapor overflow line assuming water is filling the 40 C-A-1 vessel after the interlock is activated and conservatively assuming that the waste level is 41 not decreasing due to feed valve HV-CA1-1 opening and stopping feed pump 241-AW-P-102-1. 42 Therefore, the safety function is accomplished before waste can overflow from the C-A-1 vessel 43 into the process condensate system. 44 45
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4.4.2.4.1 Failure Mode Evaluation. RPP-RPT-54584 reviewed and evaluated the C-A-1 vessel 1 waste high level control system for compliance with SIL-1 requirements as well as potential 2 failure modes that could impact the ability to meet the safety function. The evaluation results in 3 the following design requirements for the C-A-1 vessel waste high level control system. 4 5
• The C-A-1 vessel waste high level control system shall fail-safe upon a loss of power to 6 the system or any individual system component. 7
8 • The C-A-1 vessel waste high level control system shall fail-safe upon a loss of 9
communication from any or all instrumentation to the logic solver devices. 10 11
• The C-A-1 vessel waste high level control system shall fail-safe upon a loss of air supply 12 to the valves (i.e., HV-EC1-5, HV-CA1-1, HV-CA1-7, and HV-CA1-9 shall fail open). 13
14 • The C-A-1 vessel waste high level control system shall fail-safe upon a loss of control 15
voltage from the logic solver devices to the feed pump 241-AW-P-102-1 contactor and 16 upon a loss of control voltage from the logic solver devices to the HV-EC1-5, 17 HV-CA1-1, HV-CA1-7, and/or HV-CA1-9 valve solenoids. 18
19 • The C-A-1 vessel waste high level control system shall fail-safe when a detected device 20
failure occurs. (Note: Flow switches FSHH/FSL-CA1-8 and FSH/FSLL-CA1-9 output a 21 high or low flow indication for detected failures, which opens the associated safety relay. 22 The differential pressure safety trip alarm [YYC-CA1-4] outputs a fault detection signal, 23 which trips an associated fault detection safety relay.) 24
25 • The control (switching) wires between flow switches FSHH/FSL-CA1-8 and 26
FSH/FSLL-CA1-9 and enclosure CA1-ENCL-205; the control (switching) wires between 27 flow switches FSHH/FSL-CA1-8 and FSH/FSLL-CA1-9 and flow switch test boxes 28 CA1-JBX-8 and CA1-JBX-9; the control (switching) wires between enclosure 29 CA1-ENCL-205 and enclosure CA1-ENCL-206; the control (switching) wires from 30 enclosure CA1-ENCL-206 to valve solenoids HY-CA1-1A, HY-CA1-7A, HY-CA1-9A, 31 and HY-EA1-5; and the control (switching) wires from enclosure CA1-ENCL-206 to 32 enclosure CA1-ENCL-208, shall be properly insulated for the electrical and environment 33 conditions. These control wires are required to be insulated to prevent a short resulting in 34 the interlock not performing its safety function (i.e., short to power). 35
36 • The control (switching) wires and associated terminal connections (i.e., terminal blocks) 37
located inside enclosures CA1-ENCL-205, CA1-ENCL-206, and CA1-ENCL-208, and 38 inside flow switch test boxes CA1-JBX-8 and CA1-JBX-9, shall be properly insulated for 39 the electrical and environment conditions. These control wires and terminal blocks are 40 required to be insulated to prevent a short resulting in the interlock not performing its 41 safety function (i.e., short to power). 42
43 • Enclosures CA1-ENCL-205, CA1-ENCL-206, and CA1-ENCL-208 shall protect the 44
contained components from failure due to ash and dust. 45 46
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• The C-A-1 vessel waste high level control system shall be isolated from the MCS using 1 isolation devices or devices that include signal isolation. 2
3 • The instrument air lines between the flow switches and the C-A-1 vessel, originally designed 4
and installed in accordance with ASME B31.1-1973, Power Piping, have been evaluated for 5 equivalency with ASME B31.3, Process Piping (see RPP-TE-55027, 242-A Safety 6 Significant Process Piping Equivalency B31.1-1973/2004 to B31.3-2012). Future 7 modifications to these lines shall be designed and installed in accordance with American 8 Petroleum Institute (API) 570, Piping Inspection Code: In-service Inspection, Rating, Repair, 9 and Alteration of Piping Systems. Leakage or rupture of the instrument air lines between the 10 flow switches and the C-A-1 vessel is an unsafe failure mode (measured instrument air flow 11 may not reach the vessel). (Note: An unsafe failure is a failure that could prevent the C-A-1 12 vessel waste high level control system from performing its safety function.) 13
14 • The C-A-1 vessel waste high level control system shall monitor the air flow rate on both 15
sensing lines to verify air flow for accurate differential pressure measurement. 16 RPP-TE-53945 indicates that air flow rate in the sensing lines is important to both air 17 lines for different reasons. Too much air flow in the upper leg (½”I-CA1-2-M31) can 18 cause friction pressure build-up in the sensing line and create a false low differential 19 pressure reading on the differential pressure transmitter. Air flow is necessary in the 20 lower leg (½”I-CA1-3-M31) when waste is above the lower leg to provide the resistance 21 necessary to detect an increasing waste level (without air flow, the air line is at the 22 pressure of the C-A-1 headspace instead of the pressure under the waste level at the 23 sensing line elevation). 24
25 • The differential pressure transmitter shall be installed above the sensing lines. Plugged 26
differential pressure sensing lines are an unsafe failure that could result in inaccurate data 27 being transmitted to the logic solvers. Plugging may be a result of dirty or humid air 28 supply or waste migration to the sensor. Installing the transmitters above the sensing 29 lines minimizes the likelihood of plugging. 30
31 • Safety-significant air filters shall be installed upstream of the solenoid valves for valves 32
HV-EC1-5, HV-CA1-1, HV-CA1-7, and HV-CA1-9. These general purpose particulate 33 air filters shall be rated for a maximum particle size of 50 microns or smaller. The filters 34 prevent failure due to plugging as a result of dirty or moist compressed air. 35
36 • The safety-significant solenoid valves for valves HV-CA1-1, HV-CA1-7, and 37
HV-CA1-9, shall be installed downstream of the general service solenoid valve and 38 nearest to the associated valve actuator. Installing the safety-significant solenoid valves 39 nearest to valve actuator and downstream of the general service components prevents 40 failures of the general service components from affecting the safety-significant solenoid 41 valves from performing their safety function. 42
43 • The safety-significant 242-A Building is identified as a supporting SSC. It is designed to 44
not fail due to ash, snow, and wind loads, and thus protect the C-A-1 vessel waste high 45 level control system from damage due to these loads. 46
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1 • The C-A-1 vessel waste high level control system shall fail safe (i.e., prevent an overflow of 2
waste from the C-A-1 vessel into the process condensate system) in the event of a facility 3 fire. The C-A-1 vessel waste high level control system is not required to perform its safety 4 function to prevent a boil-over or carry-over of waste from the C-A-1 vessel into the process 5 condensate system in the event of a facility fire. The reason is that the resulting hazards 6 (i.e., flammable gas hazard in process condensate system piping or components, except for 7 process condensate tank TK-C-100, and chemical burn hazards [i.e., skin contact with 8 caustic waste] during process condensate sampling activities) are not an immediate hazard 9 to facility workers and are addressed as part of post-fire recovery actions. 10
11 SAC Evaporator and Pump Room Combustible Material Controls prevents unsafe 12 failures of feed valve HV-CA1-1 and dump valves HV-CA1-7 and HV-CA1-9 due to 13 fires (see Section 4.5.3). Because the C-A-1 vessel waste high level control system may 14 not fail safe from postulated fires in other areas of the facility, there is a planned design 15 improvement to ensure the C-A-1 vessel waste high level control system fails safe 16 (i.e., prevents an overflow of waste from the C-A-1 vessel into the process condensate 17 system) in the event of a facility fire (see Section 3.3.2.3.5). Until the planned design 18 improvement is completed, AC Emergency Response Actions Following Facility Fires is 19 required to address facility fires that could prevent the C-A-1 vessel waste high level 20 control system from performing its safety function to prevent an overflow of waste from 21 the C-A-1 vessel into the process condensate system (see Section 5.5.3.9). 22
23 • The C-A-1 vessel waste high level control system is not required to perform its safety function 24
during or after a seismic event (see Section 4.4.3, “C-A-1 Vessel Seismic Dump System”). 25 26
• Damage to the C-A-1 vessel waste high level control system from readily detected events 27 (i.e., load handling accidents) when there is waste in the C-A-1 vessel (i.e., in the 28 Operation Mode - see Section 5.4.1 for mode descriptions) will result in prompt 29 shutdown of the 242-A Evaporator and removal of the waste from the C-A-1 vessel if the 30 damage is determined to be significant enough to prevent the C-A-1 vessel waste high 31 level control system performing its safety function. (Note: There is also a 32 defense-in-depth feature to address this initiator. That is, the hoisting and rigging 33 program to prevent load handling accidents.) 34
35 • Damage to the C-A-1 vessel waste high level control system from readily detected events 36
(i.e., seismic events, load handling accidents, and fires) when there is limited or no waste 37 in the C-A-1 vessel (i.e., in the Limited Waste Mode or Shutdown Mode) will result in an 38 inspection and the necessary testing/repair/replacement prior to returning the C-A-1 39 vessel waste high level control system to service. (Note: There are also defense-in-depth 40 features to address these initiators. 41
42 That is, the emergency preparedness program for seismic events, the hoisting and 43 rigging program to prevent load handling accidents, and fire protection requirements to 44 address fires.) 45
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1 Based on design life and operating conditions, the ability of the C-A-1 vessel waste high level 2 control system to perform its safety function can degrade and periodic calibrations, calibration 3 checks, and functional tests are required. The calibration, calibration check, and functional test 4 frequencies are established in the SIL calculation (RPP-CALC-54586, SIL Verification 5 Calculation for 242-A Evaporator C-A-1 Vessel Waste High Level Control System) to ensure that 6 C-A-1 vessel flammable gas control system reliability meets SIL-1 requirements. 7 8 Note: The calibrations, calibration checks, and functional tests may be performed by any series 9
of sequential, overlapping, or total steps such that the system responds within the 10 required range and accuracy to known values of input and the system trip and fault 11 functions are operable. The calibrations, calibration checks, and functional tests may also 12 be accomplished, in part, by calibrations, calibration checks, and functional tests of the 13 C-A-1 vessel flammable gas control system (see Section 4.4.1) and/or the C-A-1 vessel 14 seismic dump system (see Section 4.4.3) with which the C-A-1 vessel waste high level 15 control system shares several components. 16
17 Calibrations, calibration checks, and functional tests of the C-A-1 vessel waste high level control 18 system shall be performed at least once per six months (i.e., 182 days). 19 20 Calibration is the adjustment, as necessary, of the instrumentation such that it responds within 21 the required range and accuracy to known values of input. A calibration check is performed 22 when the instrumentation cannot be calibrated (adjusted), and includes a comparison of the 23 instrumentation with other independent instrumentation, known values, or other circuits/systems 24 monitoring the same variable. Instrumentation includes the sensor, signal conditioning elements, 25 and output devices required to meet the safety function. 26 27 The differential pressure instrumentation (differential pressure transmitter and associated safety 28 trip alarm) and flow switches FSHH/FSL-CA1-8 and FSH/FSLL-CA1-9 shall be 29 calibrated/calibration checked. The as-found and as-left results of the calibrations/calibration 30 checks shall be independently verified to be within a specified range. 31 32 The functional tests of the C-A-1 vessel waste high level control system shall include the 33 following: 34 35
• VERIFY trip limits. 36 37
− 8 inch w.g. for high differential pressure trip. 38 − 3.0 standard ft3/hr for high air flow trip (FSHH/FSL-CA1-8). 39 − 0.75 standard ft3/hr for low air flow trip (FSH/FSLL-CA1-9). 40
41 Note: The trip setpoints shall account for instrumentation accuracy. 42
43
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• VERIFY timer durations. 1 2
− < 5 seconds for high differential pressure trip. 3 − < 60 seconds for low and high air flow trip (air sensing line ½”I-CA1-2-M31). 4 − < 60 seconds for low and high air flow trip (air sensing line ½”I-CA1-3-M31). 5 − < 30 minutes for opening dump valves HV-CA1-7 and HV-CA1-9). 6
7 • VERIFY with simulated or actual trip signals (i.e., high differential pressure, high air 8
flow trip [FSHH/FSL-CA1-8], OR low air flow trip [FSH/FSLL-CA1-9]) that: 9 10
17 • VERIFY the integrity of air sensing line ½”I-CA1-2-M31 and air sensing line 18
½”I-CA1-3-M31 between the flow switches (FSHH/FSL-CA1-8 and FSH/FSLL-CA1-9, 19 respectively) and C-A-1 vessel. 20
21 RPP-CALC-54586 evaluates the C-A-1 vessel waste high level control system and demonstrates 22 compliance with SIL-1 requirements. 23 24 4.4.2.5 Controls (TSRs). The C-A-1 vessel waste high level control system is an SIS whose 25 characteristics are ensured through design, procurement, installation, startup testing, 26 configuration control, and quality conformance inspections. The activities performed under 27 these programs ensure that the safety functions of the C-A-1 vessel waste high level control 28 system are preserved and protect the design baseline from inadvertent change. 29 30 The safety-significant C-A-1 vessel waste high level control system is required to be operable in 31 the Operation Mode (see Section 5.4.1 for mode descriptions). 32 33 Periodic calibrations, calibration checks, and functional test are required to ensure the operability 34 of the C-A-1 vessel waste high level control system by: 35 36
• Performing calibrations, calibration checks, and functional tests of the C-A-1 vessel 37 waste high level control system. Calibration, calibration check, and functional test 38 frequencies and requirements are as described in the system evaluation. 39
40 41 4.4.3 C-A-1 Vessel Seismic Dump System 42 43 The C-A-1 vessel seismic dump system is identified as a safety-significant SSC for natural 44 events (Section 3.3.2.4.5). 45
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1 4.4.3.1 Safety Function. The safety functions of the C-A-1 vessel seismic dump system are: 2 3
1. To drain the C-A-1 vessel via the feed line. 4 5
2. To limit the temperature of the residual waste left in the C-A-1 vessel. 6 7
3. To prevent the overflow of waste from the C-A-1 vessel into the process condensate 8 system. 9
10 Draining the C-A-1 vessel via the feed line following a seismic event prevents a flammable gas 11 accident in the C-A-1 vessel if the temperature of the residual waste left in the C-A-1 vessel is 12 limited by stopping steam to the E-A-1 reboiler and stopping recirculation pump P-B-1. 13 Preventing the overflow of waste from the C-A-1 vessel into the process condensate system 14 following a seismic event prevents a flammable gas accident and a direct radiation hazard in 15 process condensate tank TK-C-100. Preventing overflow is accomplished by stopping feed 16 pump 241-AW-P-102-1 and opening feed valve HV-CA1-1 in the feed line from 17 DST 241-AW-102 to drain the waste from the C-A-1 vessel. 18 19 4.4.3.2 System Description. The C-A-1 vessel seismic dump system is shown in 20 Figure 4.4.3-1. The C-A-1 vessel seismic dump system is manually actuated by pushing an 21 emergency stop button (i.e., HS-CA1-1 located on the external, southeast wall of the 242-A 22 Building) following a seismic event. The C-A-1 vessel seismic dump system stops feed pump 23 241-AW-P-102-1 and opens the 3-inch feed valve HV-CA1-1 in the feed line from DST 24 241-AW-102 to drain the waste from the C-A-1 vessel. Because draining the C-A-1 vessel back 25 to DST 241-AW-102 through the feed line leaves approximately 2,700 gallons of residual waste 26 in the C-A-1 vessel, the C-A-1 vessel seismic dump system also stops steam flow to the E-A-1 27 reboiler by closing steam isolation valve HV-EA1-5 and stops recirculation pump P-B-1 to stop 28 these heat sources, which limits the temperature of the residual waste left in the C-A-1 vessel. 29 30 The emergency stop button sends a signal to safety relays in enclosure CA1-ENCL-206. The 31 safety relays in CA1-ENCL-206: 32 33
• De-energize solenoid valve HY-CA1-1A, which vents the compressed air from the feed 34 valve HV-CA1-1 actuator through the instrument/process air-line (between HY-CA1-1A 35 and the HV-CA1-1 actuator) and flow control valves FCV-CA1-1 and FCV-CA1-2, to 36 open feed valve HV-CA1-1. 37
38 • De-energize solenoid valve HY-EA1-5, which vents the compressed air from the steam 39
isolation valve HV-EA1-5 actuator through the instrument/process air-line (between 40 HY-EA1-5 and the HV-EA1-5 actuator), to close steam isolation valve HV-EA1-5. 41
42 • De-energize contactor M-PAW-102A (installed in enclosure CA1-ENCL-208), which 43
stops feed pump 241-AW-P-102-1. 44 45
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• De-energize contactor M-PB-1A (installed in enclosure CA1-ENCL-207), which stops 1 recirculation pump P-B-1. 2
3 The drain path through feed valve HV-CA1-1 is shown in Figure 4.4.3-2 and includes 3”SN 4 (D to 13A), jumper 13A to 13, and 3”SN-269-M25 before entering the 241-AW-02E feed pump 5 pit. Waste then drains though feed pump 241-AW-P-102-1 to DST 241-AW-102. Valve 6 AW02E-WT-V-107 is maintained in the 180 degree position to allow back flow of waste to feed 7 pump 241-AW-P-102-1. Although not included in the C-A-1 vessel seismic dump system, waste 8 can also drain through feed control valve AW02E-WT-FCV-160, 3”SN-272-M25, and the 9 AW02A-WT-J [K-G] jumper into DST 241-AW-102. In addition to HS-CA1-1, there are two 10 other emergency stop buttons located inside the control room on walls adjacent to the 242-AB 11 Building control room entrance (south) and exit (north-east) doors. These emergency stop 12 buttons are not seismically qualified. The emergency stop buttons also open dump valves 13 HV-CA1-7 and HV-CA1-9. These valves are not seismically qualified. 14 15 The C-A-1 vessel seismic dump system is located in the 242-A Building process areas (Area 1 16 and Area 2). 17 18 RPP-RPT-53035, 242-A Evaporator C-A-1 Seismic Dump System – Functions and Requirements 19 Evaluation Document, provides additional description of the C-A-1 vessel seismic dump system. 20 21 Boundaries. The boundary of the safety-significant C-A-1 vessel seismic dump system consists 22 of the following. 23 24
• Air filter FG-EA1-5 (for supply to HY-EA1-5). 39 40
• Enclosure CA1-ENCL-206 [including safety relays K1A (HS-CA1-1), K1B 41 (HY-CA1-1A and M-PAW-102A), and K1C (HY-EA1-5 and M-PB-1A), control 42 (switching) wires (see last bullet), and terminal connections TB2 (HS-CA1-1) and TB3 43 (HY-CA1-1A; HY-EA1-5; M-PB-1A; and M-PAW-102A)]. 44
45
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• Enclosure CA1-ENCL-207 [including recirculation pump contactor M-PB-1A, pilot relay 1 K1-PB-1A, control (switching) wires (see last bullet), and terminal connection TB1]. 2
K1-PAW-102A, control (switching) wires (see last bullet), and terminal connection 5 TB1]. 6
7 • Emergency stop button HS-CA1-1, located on external, south-east wall of 242-A 8
including control (switching) wire routed from CA1-ENCL-206 to HS-CA1-1 9 (CB3FU11-SSDR1-1) and its integral contact block (terminal connection). 10
11 • Other control (switching) wires: from CA1-ENCL-206 to CA1-ENCL-207; from 12
CA1-ENCL-206 to CA1-ENCL-208; from CA1-ENCL-206 to HY-CA1-1A; and from 13 CA1-ENCL-206 to HY-EA1-5. This includes the following wires: F30CB4-FU2-SSD-8; 14 F30CB4-FU2-SSD-8B; F30CB4-FU5-SSD-20; F30CB4-FU5-SSD-20B; 15 F30CB4-FU4-SSD-16; F30CB4-FU3-SSD-12. 16
17 Note: The drain path components are not designated safety significant because they are passive 18
components and their only function is to provide a flow path to drain waste from the 19 C-A-1 vessel. The ability of the drain path to perform this function is included in the 20 system evaluation below. 21
22 Support Systems. The 242-A Building is required to protect the C-A-1 vessel seismic dump 23 system from damage due to ash, snow, and wind loads and, therefore, is designated safety 24 significant (see Section 4.4.7). In addition, the 242-A Building (Area 1, Area 2, and other 25 internal structures) is designated safety-significant to prevent its failure due to earthquake 26 (seismic) loads and, therefore, protect the C-A-1 vessel seismic dump system from damage due 27 to building and other internal structure (2 over 1) failure. (See Section 4.4.7.) 28 29 4.4.3.3 Functional Requirements. The functional requirements for the C-A-1 vessel seismic 30 dump system are, upon detection of a seismic event that could cause loss of C-A-1 vessel 31 vacuum and purge air flow, or the overflow of waste from the C-A-1 vessel into process 32 condensate tank TK-C-100, to (1) stop feed pump 241-AW-P-102-1 and open feed valve 33 HV-CA1-1 to drain the C-A-1 vessel, and (2) close steam isolation valve HV-EA1-5 and stop 34 recirculation pump P-B-1 to stop heat sources to the residual waste left in the C-A-1 vessel. 35 (Note: The C-A-1 vessel seismic dump system is not required to drain the vessel during the 36 seismic event, but rather following the event.) 37 38 There are no other functional/performance requirements derived from the hazard and accident 39 analyses, but additional requirements necessary to satisfy the safety function are developed in the 40 system evaluation (see Section 4.4.3.4). 41 42 4.4.3.4 System Evaluation. The system evaluation of the C-A-1 vessel seismic dump system is 43 documented in RPP-RPT-53035. The evaluation identifies the functional/performance 44 requirements necessary for the C-A-1 vessel seismic dump system to perform its safety 45 functions. The evaluation also identifies and evaluates potential failure modes of the C-A-1 46 vessel seismic dump system considering the conditions and events in which the safety functions 47
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must be met. In addition, the evaluation identifies and evaluates support systems whose function 1 is required for the C-A-1 vessel seismic dump system to perform its safety functions and 2 interfaces whose failure could prevent the C-A-1 vessel seismic dump system from performing 3 its safety functions. The evaluation results are summarized in Table 4.4.3-1. The system 4 evaluation satisfies DOE and TOC requirements to ensure the reliable performance of safety-5 significant SSCs to meet the safety function(s) determined from the hazard and accident 6 analyses. 7 8 The primary functional/performance requirement is to stop feed pump 241-AW-P-102-1, open 9 feed valve HV-CA1-1, close steam valve HV-EA1-5, and stop recirculation pump P-B-1 if an 10 emergency stop button is actuated (in the event of a severe earthquake). Stopping feed pump 11 241-AW-P-102-1 and opening feed valve HV-CA1-1 allows waste to drain back to DST 12 241-AW-102 through the feed line, which leaves approximately 2,700 gallons of residual waste 13 in the C-A-1 vessel. Closing steam isolation valve HV-EA1-5 (i.e., stopping steam to the E-A-1 14 reboiler) and stopping recirculation pump P-B-1 limits heat input to the residual waste left in the 15 C-A-1 vessel. The evaluation of preventing a flammable gas hazard in the C-A-1 vessel by 16 draining through feed valve HV-CA1-1, closing steam isolation valve HV-EA1-5, and stopping 17 recirculation pump P-B-1 is described in Section 4.4.1. 18 19 The requirement to stop feed pump 241-AW-P-102-1, open feed valve HV-CA1-1, close steam 20 isolation valve HV-EA1-5, and stop recirculation pump P-B-1 if the emergency stop button is 21 actuated (in the event of a severe earthquake) is met by system design and evaluation for 22 operation following a PC-2 seismic event. The safety-significant components are seismically 23 qualified in accordance with the American Society of Civil Engineers (ASCE) 7-05, Minimum 24 Design Loads for Buildings and Other Structures, Table 13, and TFC-ENG-STD-06, Design 25 Loads for Tank Farm Facilities. 26 27 All piping and components in the C-A-1 vessel seismic dump system drain path have been 28 evaluated and concluded to be able to provide the required drain path following a PC-2 seismic 29 event as described in RPP-RPT-52517, 242-A Evaporator Facility Assessment for Performance 30 Category 2 Natural Phenomena Hazard. 31 32 The C-A-1 vessel seismic dump system is located in the 242-A Building and is designed for 33 applicable process conditions (exposure to waste, steam, and/or instrument air) and 34 environmental conditions, which results in requirements on design pressure, design temperature, 35 material compatibility, and valve actuator torque, as well as protection from exposure to air 36 compressor oil, ash, and dust. 37 38 The C-A-1 vessel seismic dump system is not automatically initiated upon detection of a seismic 39 event, but is initiated by an emergency stop button. To prevent heat up of the waste in the C-A-1 40 vessel, steam isolation valve HV-EA1-5 must be closed within minutes and recirculation pump 41 P-B-1 must be stopped within hours. To prevent the overflow of waste from the C-A-1 vessel 42 into the process condensate system, feed pump 241-AW-P-102-1 must be stopped within 43 approximately 40 min. (see Section 4.4.2.4). There is a planned design improvement to 44 automatically initiate the C-A-1 vessel seismic dump system upon detection of a seismic event 45 (e.g., a seismic switch) (see Section 3.3.2.3.5). Until the planned design improvement is 46 completed, AC Key Element Emergency Preparedness requires that emergency response 47
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procedures include actuating the C-A-1 vessel seismic dump system, stopping the steam to the 1 E-A-1 reboiler, shutting down feed pump 241-AW-P-102, shutting down air compressors 2 CP-E-1 and CP-E-2, and evacuating personnel for the condenser room (see Section 5.5.3.6). 3 (Note: Shutting down recirculation pump P-B-1 is not included as a required emergency action 4 because the heat input from recirculation pump P-B-1 operation is small relative to steam to the 5 E-A-1 reboiler.) 6 7 4.4.3.4.1 Failure Mode Evaluation. RPP-RPT-53035 reviewed and evaluated the C-A-1 vessel 8 seismic dump system for potential failure modes that could impact the ability to meet the safety 9 function. Where the C-A-1 vessel seismic dump system is not designed to withstand the cause of 10 the identified failure mode, the risk of the resulting hazard is low, the failure mode is readily 11 detected, or defense-in-depth features are provided. The results of the evaluation are 12 summarized below. 13 14
• The C-A-1 vessel seismic dump system shall fail-safe upon a loss of power to the system 15 or any individual interlock, contactor, or solenoid. 16
17 • The C-A-1 vessel seismic dump system shall fail-safe upon a loss of air supply to the 18
valves (i.e., feed valve HV-CA1-1 shall fail open and steam isolation valve HV-EA1-5 19 shall fail closed). 20
21 • The safety-significant solenoid valve for feed valve HV-CA1-1 shall be installed 22
downstream of the general service solenoid valve and nearest to the valve actuator. The 23 safety-significant solenoid valve for steam isolation valve HV-EA1-5 shall be installed in 24 the AMU Room near the wall penetration for the air line to the outside valve actuator. 25 Installing the safety-significant solenoid valves nearest to valve and downstream of the 26 general service components prevents failures of the general service components from 27 affecting the safety-significant solenoid valves from performing their safety function. 28
29 • Safety-significant air filters shall be installed in the air supply to HY-CA1-1 (and 30
FCV-CA1-1 and FCV-CA1-2) and HY-EA1-5. These general purpose particulate air 31 filters shall be rated for a maximum particle size of 50 microns or smaller. The filters 32 prevent failure due to plugging as a result of dirty compressed air. 33
34 • The control (switching) wire from emergency stop button HS-CA1-1 to enclosure 35
CA1-ENCL-206, from enclosure CA1-ENCL-206 to enclosure CA1-ENCL-207, from 36 enclosure CA1-ENCL-206 to enclosure CA1-ENCL-208, and from enclosure 37 CA1-ENCL-206 to solenoid valves HY-CA1-1A and HY-EA1-5, shall be properly 38 insulated for the electrical and environment conditions. These control wires are required 39 to be insulated to prevent a short resulting in the interlock not performing its safety 40 function (i.e., short to power). 41
42
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• The control (switching) wires and associated terminal connections (i.e., terminal blocks) 1 located inside enclosures CA1-ENCL-206, CA1-ENCL-207, and CA1-ENCL-208; and 2 the control (switching) wire inside the emergency stop button HS-CA1-1 from enclosure 3 CA1-ENCL-206 and the associated terminal connection, shall be properly insulated for 4 the electrical and environment conditions. These control wires and terminal blocks are 5 required to be insulated to prevent a short resulting in the interlock not performing its 6 safety function (i.e., short to power). 7
8 • The control (switching) wire from emergency stop button HS-CA1-1 to enclosure 9
CA1-ENCL-206, from enclosure CA1-ENCL-206 to enclosure CA1-ENCL-207, from 10 enclosure CA1-ENCL-206 to enclosure CA1-ENCL-208, and from enclosure 11 CA1-ENCL-206 to solenoid valves HY-CA1-1A and HY-EA1-5, shall be: 12
13 - Seismically qualified (i.e., evaluated and/or protected from seismic interactions), or 14
15 - Installed in a separate conduit from the control power (+) wire and other control 16
(switching) wires. 17 18 This prevents a short resulting in the system not performing its safety function (i.e., short 19 to power) caused by a seismic event (i.e., impact). 20
21 • The emergency stop button HS-CA1-1 and enclosures CA1-ENCL-206, CA1-ENCL-207, 22
and CA1-ENCL-208 shall protect the contained components from failure due to ash and 23 dust. 24
25 • The safety-significant 242-A Building is identified as a supporting SSC. It is designed to 26
not fail due to ash, snow, and wind loads, and thus protects the C-A-1 vessel seismic 27 dump system from damage due to building (2 over 1) failure from these loads. The 28 242-A Building (Area 1, Area 2, and other internal structures) is also designed to not fail 29 due to earthquake (seismic) loads and thus protects the C-A-1 vessel seismic dump 30 system from damage due to building and other internal structure (2 over 1) failure from 31 this load. 32
33 • The C-A-1 vessel seismic dump system shall fail safe (i.e., prevent a flammable gas 34
accident in the C-A-1 vessel and prevent a flammable gas accident and high radiation 35 hazard in process condensate tank TK-C-100) in the event of post-seismic event fires. 36 SAC Evaporator and Pump Room Combustible Material Controls prevents unsafe 37 failures of feed valve HV-CA1-1 and dump valves HV-CA1-7 and HV-CA1-9 due to 38 fires (see Section 4.5.3). Because the C-A-1 vessel flammable gas control system may 39 not fail safe from postulated fires in other areas of the facility, there is a planned design 40 improvement to automatically initiate the C-A-1 vessel seismic dump system upon 41 detection of a seismic event (e.g., a seismic switch) (see Section 3.3.2.3.5). 42 Automatically initiating the C-A-1 vessel seismic dump system ensures system actuation 43 before post-seismic event fires can impact the system. Until the planned design 44 improvement is completed, AC Key Element Emergency Preparedness requires that 45 emergency response procedures include actuating the C-A-1 vessel seismic dump system, 46
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stopping the steam to the E-A-1 reboiler, shutting down feed pump 241-AW-P-102, 1 shutting down air compressors CP-E-1 and CP-E-2, and evacuating personnel for the 2 condenser room (see Section 5.5.3.6). 3
4 • Damage to the C-A-1 vessel seismic dump system from readily detected events (i.e., load 5
handling accidents and fires) when there is waste in the C-A-1 vessel (i.e., in the 6 Operation Mode - see Section 5.4.1 for mode descriptions) will result in prompt 7 shutdown of the 242-A Evaporator and removal of the waste from the C-A-1 vessel if the 8 damage is determined to be significant enough to prevent the C-A-1 vessel seismic dump 9 system from performing its safety function. (Note: There are also defense-in-depth 10 features to address these initiators. That is, the hoisting and rigging program to prevent 11 load handling accidents, and fire protection requirements to address fires). 12
13 • Damage to the C-A-1 vessel seismic dump system from readily detected events (i.e., load 14
handling accidents and fires) when there is limited or no waste in the C-A-1 vessel 15 (i.e., in the Limited Waste Mode or Shutdown Mode) will result in an inspection and the 16 necessary testing/repair/replacement prior to returning the C-A-1 vessel seismic dump 17 system to service. (See also the note in the bullet above.) 18 19
• The instrument air line (3/4” IA-735-M7) that supplies air to the steam isolation valve 20 HV-EA1-5 actuator shall include safety-significant airline accumulators 242AE1-IA-ACC-001 21 and 242AE1-IA-ACC-002 upstream sized for a minimum of one complete actuator air 22 exchange to ensure the air is supplied to the solenoid valve and steam valve actuator is within 23 the temperature ratings of the components. 24
25 • The instrument air line (3/4” IA-735-M7) that supplies air to the steam isolation valve 26
HV-EA1-5 actuator shall be sloped outside the facility. Each low point location shall 27 include a drain valve for periodic blowdown of line to prevent the air line from becoming 28 plugged with condensation. 29
30 Based on design life and operating conditions, the ability of the C-A-1 vessel seismic dump 31 system to perform its safety function can degrade and periodic testing is required. Functional 32 testing of the C-A-1 vessel seismic dump system shall be performed at least once per six months 33 (i.e., 182 days). The surveillance frequency of 182 days is established consistent with the 34 surveillance frequency of the C-A-1 vessel flammable gas control system (see Section 4.4.1) 35 because the C-A-1 vessel seismic dump system shares several components (e.g., feed valve 36 HV-CA1-1, steam isolation valve HV-EA1-5, feed pump 241-AW-P-102-1 contactor 37 M-PAW-102A, recirculation pump P-B-1 contactor M-PB-1A) with this system. 38 39 Note: The functional tests of the C-A-1 vessel seismic dump system may be accomplished, in 40
part, by functional tests of the C-A-1 vessel flammable gas control system (see 41 Section 4.4.1) and/or the C-A-1 vessel waste high level control system (see Section 4.4.2) 42 with which the C-A-1 vessel seismic dump system shares several components. 43
44
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The functional tests of the C-A-1 vessel seismic dump system shall verify with a simulated or 1 actual trip signal (i.e., emergency stop button HS-CA1-1 is actuated) that: 2 3
8 Other functional tests of the C-A-1 vessel seismic dump system include: 9 10
• Verify a clear flow path of instrument air line ¾” IA-735-M7 by sequentially opening 11 drain valves 242AO-IA-V-005 and 242AO-IA-V-004 with air supplied to HV-EA1-5 12 allowing collected condensation and oil to be purged. 13
14 • Verify adequate closure of the steam isolation valve while steam is on and water is in the 15
C-A-1 vessel by closing HV-EA1-5 and verifying the differential temperature across the 16 reboiler is less than or equal to 0.8°F. 17
18 RPP-TE-58237 provides details and justification for the steam valve closure functional test. 19 20 4.4.3.5 Controls (TSRs). The C-A-1 vessel seismic dump system characteristics are ensured 21 through design, procurement, installation, startup testing, configuration control, and quality 22 conformance inspections. The activities performed under these programs ensure that the safety 23 functions of the C-A-1 vessel seismic dump system are preserved and protect the design baseline 24 from inadvertent change. 25 26 The safety-significant C-A-1 vessel seismic dump system is required to be operable in the 27 Operation Mode (see Section 5.4.1 for mode definitions). 28 29 Periodic functional tests are required to ensure the operability of the C-A-1 vessel seismic dump 30 system by: 31 32
• Performing functional tests of the C-A-1 vessel seismic dump system. The frequency and 33 criteria are as described in the system evaluation. 34
35 4.4.4 E-A-1 Reboiler 36 37 The E-A-1 reboiler is identified as a safety-significant SSC for flammable gas accidents 38 (Section 3.3.2.4.1) and waste leaks and misroutes (Section 3.3.2.4.3). 39 40 4.4.4.1 Safety Functions(s). The safety function of the E-A-1 reboiler is to provide 41 confinement of waste (i.e., E-A-1 reboiler tube/tube sheet integrity). Providing confinement of 42 waste protects facility workers from a flammable gas accident in the steam condensate system 43 due to waste in the steam condensate system resulting from an E-A-1 reboiler tube/tube sheet 44 leak/failure (i.e., accumulation of flammable gas generated by waste in the steam condensate 45 system piping or components). Providing confinement of waste also protects facility workers 46
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from direct radiation hazards and chemical burn hazards (i.e., skin contact with caustic waste) 1 during steam condensate sampling activities due to waste in the steam condensate system 2 resulting from an E-A-1 reboiler tube/tube sheet leak/failure. (Note: The direct radiation hazard 3 is only from waste misrouted into steam condensate weir box TK-C-103.) 4 5 4.4.4.2 System Description. The E-A-1 reboiler is a single-pass shell and tube heat exchanger. 6 The reboiler is located downstream of recirculation pump P-B-1 and waste flows from the 7 bottom of the heat exchanger, through the internal tubes and exits at the top of the exchanger 8 before entering the C-A-1 vessel. Counter flowing steam enters the shell side at the top of the 9 heat exchanger and exits at the bottom. The tube sheets are fabricated from 1-1/4-in stainless 10 steel plate and the tubes are 14 gauge (0.083 inch wall) stainless steel tubing. 11 12 Two boilers in the Johnson Controls Industries (JCI) Boiler Annex provide saturated steam. 13 During the heating process, the steam is reduced to condensate in the reboiler. This condensate 14 then drains to the Treated Effluent Disposal Facility (TEDF), via steam condensate weir box 15 TK-C-103, or is diverted to DST 241-AW-102 upon detection of radiation in the condensate. 16 When the steam supply is isolated from the reboiler, the pressure control loop maintains 18 lb/in2 17 gauge air in the reboiler shell. 18 19 When process activities are ongoing, and steam is supplied to the reboiler, the pressure control 20 loop limits air pressure. RPP-RPT-52352, 242-A Evaporator E-A-1 Reboiler – Functions and 21 Requirements Evaluation Document, provides additional description of the E-A-1 reboiler. 22 23 Boundaries. The boundary of the safety-significant E-A-1 reboiler is the tube sheets and the 24 exchanger tubes that provide the waste pressure boundary that maintains separation between the 25 waste stream and the steam used for heating. 26 27 Support Systems. The 242-A Building is required to protect the E-A-1 reboiler from damage 28 due to ash, snow, and wind loads and, therefore, is designated safety significant (see 29 Section 4.4.7). 30 31 4.4.4.3 Functional Requirements. The functional requirement for the E-A-1 reboiler is no 32 leakage of waste (leak tight pressure boundary). 33 34 There are no other functional/performance requirements derived from the hazard and accident 35 analyses, but additional requirements necessary to satisfy the safety function are developed in the 36 system evaluation (see Section 4.4.4.4). 37 38 4.4.4.4 System Evaluation. The system evaluation of the E-A-1 reboiler is documented in 39 RPP-RPT-52352. The evaluation identifies the functional/performance requirements necessary 40 for the E-A-1 reboiler to perform its safety function. The evaluation also identifies and evaluates 41 potential failure modes of the E-A-1 reboiler considering the conditions and events in which the 42 safety function must be met. In addition, the evaluation identifies and evaluates support systems 43 whose function is required for the E-A-1 reboiler to perform its safety function and interfaces 44 whose failure could prevent the E-A-1 reboiler from performing its safety function. The system 45 evaluation satisfies DOE and TOC requirements to ensure the reliable performance of safety-46
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significant SSCs to meet the safety function(s) determined from the hazard and accident 1 analyses. 2 3 The primary functional/performance requirement is to provide a leak tight pressure boundary. 4 This requirement is met by designing the E-A-1 reboiler to the requirements of the American 5 Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, Section VIII, 6 Division 1 and testing the E-A-1 reboiler to 1.5 times the design pressure (which was done prior 7 to placing the E-A-1 reboiler in service). 8 9 The E-A-1 reboiler is designed for applicable process (waste, steam, and compressed air) and 10 environmental conditions, which results in requirements on design pressure, design temperature, 11 and material compatibility. Functional/performance requirements including design pressure, 12 design temperature, and materials of construction are documented in RPP-RPT-52352, which 13 also demonstrates the design adequacy of the E-A-1 reboiler. 14 15 In addition, defense-in-depth feature E-A-1 reboiler chemistry and flush requirements provides 16 an additional layer of defense for E-A-1 reboiler tube/tube sheet integrity that could be degraded 17 by corrosion. 18 19 4.4.4.4.1 Failure Mode Evaluation. RPP-RPT-52352 reviewed and evaluated the E-A-1 20 reboiler for potential failure modes that could impact the ability to meet the safety function. The 21 evaluation results are summarized in Table 4.4.4-1. Where the E-A-1 reboiler is not designed to 22 withstand the cause of the identified failure mode, the risk of the resulting hazard is low, the 23 failure mode is readily detected, or defense-in-depth features are provided. The results of the 24 evaluation are summarized below. 25 26
• The safety-significant 242-A Building is identified as a supporting SSC. It is designed to 27 not fail due to ash, snow, and wind loads, and thus protects the E-A-1 reboiler from 28 damage due to these loads. 29
30 • The E-A-1 reboiler is not required to perform its safety function during or after a seismic 31
event (see Section 5.5.3.6, “Administrative Control 5.9.6 - Emergency Preparedness”). 32 33
• Damage to the E-A-1 reboiler from readily detected events (i.e., fires) when there is 34 waste in the C-A-1 vessel (i.e., in the Operation Mode - see Section 5.4.1 for mode 35 descriptions) will result in prompt shutdown of the 242-A Evaporator and removal of the 36 waste from the C-A-1 vessel if the damage is determined to be significant enough to 37 prevent the E-A-1 reboiler from performing its safety function. (Note: There is also a 38 defense-in-depth feature to address this initiator. That is, the fire protection requirements 39 address fires.) 40
41 • Damage to the E-A-1 reboiler from readily detected events (i.e., seismic events, load 42
handling accidents, and fires) when there is limited or no waste in the C-A-1 vessel 43 (i.e., in the Limited Waste Mode or Shutdown Mode) will result in an inspection and the 44 necessary testing/repair/replacement prior to returning the E-A-1 reboiler to service. 45 (Note: There are also defense-in-depth features to address some of these initiators. For 46
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example, the hoisting and rigging program to prevent load handling accidents, and fire 1 protection requirements to address fires.) 2
3 Based on design life and operating conditions, the ability of the E-A-1 reboiler to perform its 4 safety function can degrade and periodic testing is required. The following test has been 5 established. 6 7
• A leak test of the tube/tube sheet is required every five years. The leak test can be 8 performed in either of two ways. 9
10 − Pneumatic pressure decay leak test where the shell side is pressurized to 16 - 18 lb2/in 11
gauge and held for a minimum of 10 min with no decrease in pressure. 12 13
− A liquid tracer leak test where tracer (e.g., fluorescein) is mixed into water in the 14 C-A-1 vessel and held for 24 hours with the C-A-1 vessel water level at or above the 15 normal operating level and the E-A-1 reboiler shell side at atmospheric pressure. The 16 sensitivity of the test shall not be less than one drop/hr. 17
18 4.4.4.5 Controls (TSRs). The E-A-1 reboiler is a passive design feature whose characteristics 19 are ensured through design, procurement, installation, startup testing, configuration control, and 20 quality conformance inspections. The activities performed under these programs ensure that the 21 safety function of the E-A-1 reboiler is preserved and protect the design baseline from 22 inadvertent change. 23 24 The safety-significant E-A-1 reboiler is required to be operable in the Operation Mode (see 25 Section 5.4.1 for mode definitions). 26 27 In-service inspections/tests are required to ensure the operability of the E-A-1 reboiler by: 28 29
• Performing a leak test every five years. The test criteria are as described in the system 30 evaluation. 31
32 4.4.5 Backflow Prevention Devices (PSV-RW-3 and BFP-RW-11) 33 34 Backflow prevention devices PSV-RW-3 and BFP-RW-11 are identified as safety-significant 35 SSCs for flammable gas accidents (Section 3.3.2.4.1) and waste leaks and misroutes 36 (Section 3.3.2.4.3). 37 38 4.4.5.1 Safety Function(s). There are two safety functions applicable to both devices: 39 40
1. To limit the backflow of waste into the raw water system in a non-radiologically 41 controlled area. Limiting the backflow of waste into the raw water system in a 42 non-radiologically controlled area protects facility workers from chemical burns due to a 43 wetting spray/jet/stream leak. 44
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2. To prevent the backflow of waste into the raw water system. Preventing the backflow of 1 waste into the raw water system protects facility workers from a flammable gas accident 2 (i.e., accumulation of flammable gas generated by waste in the raw water system piping 3 or components). 4
5 4.4.5.2 System Description. Backflow prevention device PSV-RW-3 (see Figure 4.4.5-1) 6 consists of a 2-inch check valve/vacuum break with 2-inch inlet and discharge piping connected 7 to the raw water line supply for three raw water lines supporting flushes to dip tubes in the C-A-1 8 vessel, dump valves HV-CA1-7 and HV-CA1-9, and slurry flush valves HV-CA1-2 and 9 HV-CA1-2A (see Figure 4.4.5-3). The check valve has a low cracking pressure spring and 10 allows airflow into the piping in the event a vacuum occurs. Isolation ball valves (5-32 and 11 5-33), test port with isolation ball valve (5-28), and test port/drain with isolation ball valve 12 (5-28A) are included to allow the system to be drained of water and provide a test port for a 13 vacuum pump and pressure monitoring instrumentation. These components support periodic 14 testing of the check valve by allowing a vacuum to be placed on PSV-RW-3 to verify its 15 functionality. PSV-RW-3 (valve and associated piping) is installed horizontally level with or 16 above the raw water pipe in which it is installed. 17 18 Backflow prevention device BFP-RW-11 is shown in Figure 4.4.5-2 and is installed in the raw 19 water line to the waste slurry sampler in the load-out and hot-equipment storage room (see 20 Figure 4.4.5-3). BFP-RW-11 consists of two 1-inch isolation ball valves (RWV-16 and 21 RWV-17) located upstream and downstream of two 1-inch check valves (V1 and V2) with 22 ¼-inch test ports located upstream, in-between, and downstream of the check valves. Each test 23 port has its own ¼-inch isolation ball valve. Unions are located upstream and downstream of 24 each check valve to facilitate installation and removal. 25 26 (Note: The upstream and downstream test ports along with their isolation valves [RWV-18, 27 RWV-19, and RWV-21] and their associated piping are only needed to support functional testing 28 prior to installation.) 29 30 RPP-RPT-51829, 242-A Evaporator BFP-RW-11 and PSV-RW-3 Backflow Prevention Devices – 31 Functions and Requirements Evaluation Document, provides additional description of backflow 32 prevention devices PSV-RW-3 and BFP-RW-11. 33 34 Boundaries. The safety-significant backflow prevention device PSV-RW-3 consists of check 35 valve/vacuum break PSV-RW-3 and its associated inlet and discharge piping. All other valves 36 and piping are general service. 37 38 Note: The inlet and discharge piping associated with PSV-RW-3 are included in the safety-39
significant boundary because their physical characteristics (e.g., inside diameter, length, 40 surface roughness, number and type of elbows/reducers) are important assumptions in the 41 sizing the check valve/vacuum break. 42
43 The safety-significant backflow prevention devices BFP-RW-11 consists of two check valves 44 (V1 and V2). All other valves, test ports, and piping are general service. 45 46
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Support Systems. The 242-A Building is required to protect backflow prevention devices 1 PSV-RW-3 and BFP-RW-11 from damage due to ash, snow, and wind loads and, therefore, is 2 designated safety significant (see Section 4.4.7). 3 4 4.4.5.3 Functional Requirements. The functional requirements for the backflow prevention 5 devices are as follows. 6 7
1. To protect facility workers from chemical burns due to a wetting spray/jet/stream leaks, 8 the functional requirement is to limit the backflow of waste (i.e., leak rate) to 9 ≤ 0.1 gal/min into non-radiologically controlled areas. 10
11 2. To protect facility workers from a flammable gas deflagration in raw water piping, the 12
functional requirement is no backflow of waste (i.e., zero leak rate). 13 14 There are no other functional/performance requirements derived from the hazard and accident 15 analyses, but additional requirements necessary to satisfy the safety function are developed in the 16 system evaluation (see Section 4.4.5.4). 17 18 4.4.5.4 System Evaluation. The system evaluation of the backflow prevention devices 19 PSV-RW-3 and BFP-RW-11 is documented in RPP-RPT-51829. The evaluation identifies the 20 functional/performance requirements necessary for the backflow prevention devices to perform 21 their safety functions. The evaluation also identifies and evaluates potential failure modes of the 22 backflow prevention devices considering the conditions and events in which the safety function 23 must be met. In addition, the evaluation identifies and evaluates support systems whose function 24 is required for the backflow prevention devices to perform their safety functions and interfaces 25 whose failure could prevent the backflow prevention devices from performing their safety 26 functions. The system evaluation satisfies DOE and TOC requirements to ensure the reliable 27 performance of safety-significant SSCs to meet the safety function(s) determined from the 28 hazard and accident analyses. 29 30 PSV-RW-3. The hazards controlled by PSV-RW-3 involve backflow by back-siphoning of 31 waste up raw water lines connected to the C-A-1 vessel (dip tubes), dump valves HV-CA1-7 and 32 HV-CA1-9, and slurry flush valves HV-CA1-2 and HV-CA1-2A due to a loss of water pressure 33 and raw water leaking/draining when a flow path is open to the waste (dip tube flushing 34 operations, open flush valves). Backflow by back-siphoning of waste is through the raw water 35 line on the fifth floor of the condenser room. 36 37 PSV-RW-3 is installed on the raw water line on the fifth floor of the condenser room. The valve 38 opens to allow air to flow into the raw water piping upon a vacuum condition, preventing back-39 siphoning from occurring. The primary functional/performance requirement for PSV-RW-3, 40 therefore, is to prevent back-siphoning by limiting the potential vacuum in the raw water line 41 from exceeding 8.3 lb/in2 differential (difference between the hydrostatic head of the waste 42 column from the top of the waste in the C-A-1 vessel to the elevation of the raw water line on the 43 fifth floor of the condenser room assuming a conservatively low specific gravity for the waste of 44 1.0). (Note: This is equivalent to preventing the pressure in the raw water line from dropping 45 below 6.4 lb/in2 absolute.) Design calculations in RPP-CALC-52079, PSV-RW-3 and 46 BFP-RW-11 ASME B31.1 Analysis, Support Analysis, and PSV-RW-3 Flow Analysis, result in a 47
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cracking pressure of ≤ 3 lb/in2 differential and an air flow capacity of ≥ 1.6 ft3/s. The cracking 1 pressure is verified by a functional test. The inlet piping to PSV-RW-3 is straight for at least ten 2 pipe diameters to ensure even flow through the check valve. 3 4 PSV-RW-3 is also designed for applicable process (raw water) and environmental conditions, 5 which results in requirements on design pressure, design temperature, and materials of 6 construction. Functional/performance requirements including design pressure, design 7 temperature, and materials of construction are documented in RPP-RPT-51829, which also 8 demonstrates the design adequacy of PSV-RW-3. 9 10 BFP-RW-11. The hazards controlled by BFP-RW-11 involve waste backflow from the waste 11 slurry sampler. When the waste slurry sample is withdrawn from the waste stream, it is pulled 12 back into a small chamber where it drops out into a sample vial. This sampling chamber has a 13 rinse water line piped into it for the purpose of cleaning the sampler. If a valve between the 14 piston sampler and sample vial were closed, and if the seals on the piston were degraded, waste 15 could potentially flow back into the raw water line due to back-pressurization or siphoning (if the 16 raw water line is ruptured or opened). This hazard is present in the Operation Mode and Limited 17 Waste Mode (see 5.4.1 for mode descriptions). The primary functional/performance requirement 18 for BFP-RW-11, therefore, is to prevent backflow (zero through valve leakage) due to back-19 pressurization or siphoning. To provide adequate reliability and address the potential for failure 20 due to fouling conditions, two check valves are required in series. BFP-RW-11 valves V1 and 21 V2 are spring to close and must not open when a pressure of 1.0 lb/in2 differential is applied in 22 the direction of normal flow. The leak tightness (zero through valve leakage) and opening 23 differential pressure is verified by a functional test. In the unlikely event that a particle gets 24 wedged in one of the check valves, the second check valve can perform the safety function. It is 25 judged to be “beyond extremely unlikely” that a particle could get wedged in both check valves 26 simultaneously. (Note: The hazards are eliminated if BFP-RW-11 is removed and an air gap is, 27 therefore, created in the raw water line.) 28 29 BFP-RW-11 is also designed for applicable process (raw water) and environmental conditions, 30 which results in requirements on design pressure, design temperature, and materials of 31 construction. Functional/performance requirements including design pressure, design 32 temperature, and materials of construction are documented in RPP-RPT-51829, which also 33 demonstrates the design adequacy of BFP-RW-11. 34 35 4.4.5.4.1 Failure Mode Evaluation. RPP-RPT-51829 reviewed and evaluated backflow 36 prevention devices PSV-RW-3 and BFP-RW-11 for potential failure modes that could impact the 37 ability to meet the safety function. The evaluation results are summarized in Table 4.4.5-1. 38 Where PSV-RW-3 and BFP-RW-11 are not designed to withstand the cause of the identified 39 failure mode, the risk of the resulting hazard is low, the failure mode is readily detected, or 40 defense-in-depth features are provided. The results of the evaluation are summarized below. 41 42
• The safety-significant 242-A Building is identified as a supporting SSC. It is designed to 43 not fail due to ash, snow, and wind loads, and thus protects PSV-RW-3 and BFP-RW-11 44 from damage due to these loads. 45
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• The backflow prevention devices are not required to perform their safety function during 1 or after a seismic event (see Section 5.5.3.6, “Administrative Control 5.9.6 – Emergency 2 Preparedness”). 3
4 • Damage to the backflow prevention devices from readily detected events (i.e., load 5
handling accidents and fires) when there is waste in the C-A-1 vessel (i.e., in the 6 Operation Mode for PSV-RW-3 and in the Operation Mode and Limited Waste Mode for 7 BFP-RW-11 - see Section 5.4.1 for mode descriptions) will result in prompt shutdown of 8 the 242-A Evaporator and removal of the waste from the C-A-1 vessel (or BFP-RW-11 9 will be removed from the raw water line creating an air gap) if the damage is determined 10 to be significant enough to prevent the backflow prevention devices from performing 11 their safety function. (Note: There are also defense-in-depth features to address these 12 initiators. That is, the hoisting and rigging program prevents load handling accidents, and 13 fire protection requirements to address fires.) 14
15 • Damage to the backflow prevention devices from readily detected events (i.e., seismic 16
events, load handling accidents, and fires) when there is limited or no waste in the C-A-1 17 vessel (i.e., in the Limited Waste Mode or Shutdown Mode for PSV-RW-3 and Shutdown 18 Mode for BFP-RW-11) will result in an inspection and the necessary testing/repair/ 19 replacement prior to returning the backflow prevention devices to service. (See also the 20 note in the bullet above). 21
22 Based on design life and operating conditions, the ability of PSV-RW-3 and BFP-RW-11 to 23 perform their safety functions can degrade and periodic testing is required. The following tests 24 have been established. 25 26 PSV-RW-3. PSV-RW-3 shall be tested annually to verify the check valve/vacuum break 27 cracking pressure is ≤ 3 lb/in2. No degradation mechanism has been identified for the inlet and 28 discharge piping and no testing is required. 29 30 BFP-RW-11. BFP-RW-11 shall be leak tested annually to verify that check valves V1 and V2 31 are each drip tight in the direction of flow until the differential pressure across the valve is at 32 ≥ 1.0 lb/in2. 33 34 4.4.5.5 Controls (TSRs). Backflow prevention devices PSV-RW-3 and BFP-RW-11 are 35 generally passive design features whose characteristics are ensured through design, procurement, 36 installation, startup testing, configuration control, and quality conformance inspections. The 37 activities performed under these programs ensure that the safety functions of backflow 38 prevention devices PSV-RW-3 and BFP-RW-11 are preserved and protect the design baseline 39 from inadvertent change. 40 41 Safety-significant backflow prevention devices PSV-RW-3 and BFP-RW-11 are required to be 42 operable in the Operation Mode (see Section 5.4.1 for mode definitions). In addition, backflow 43 prevention device BFP-RW-11 is required to be operable in the Limited Waste Mode or removed 44 from the raw water line (i.e., air gap). 45 46
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In-service inspections/tests are required to ensure the operability of backflow prevention devices 1 PSV-RW-3 and BFP-RW-11 by: 2 3
• Backflow prevention device PSV-RW-3 shall be tested annually (i.e., every 365 days) to 4 verify the check valve/vacuum break cracking pressure is ≤ 3 lb/in2. 5
6 • Backflow prevention device BFP-RW-11 shall be tested annually (i.e., every 365 days) to 7
verify that check valves V1 and V2 are each drip tight in the direction of flow until the 8 differential pressure across the valve is ≥ 1 lb/in2. 9
10 11 4.4.6 Pressure Relief Valve (PSV-PB2-1) 12 13 Pressure relief valve PSV-PB2-1 is identified as a safety-significant SSC for waste leaks and 14 misroutes (Section 3.3.2.4.3). 15 16 4.4.6.1 Safety Function(s). The safety function of pressure relief valve PSV-PB2-1 is to limit 17 slurry pump P-B-2 discharge pressure. Limiting the slurry pump P-B-2 discharge pressure 18 decreases the consequences of a fine spray leak. 19 20 4.4.6.2 System Description. Pressure relief valve PSV-PB2-1 is located inside the pump room 21 on the discharge transfer line of slurry pump P-B-2. The pressure relief valve is connected to the 22 top of the waste transfer primary piping, is oriented vertically, and located close to the fluid 23 stream (transfer line). PSV-PB2-1 includes a bellows. The discharge from the pressure relief 24 valve is sloped downward from the pressure relief valve to the pump room sump. The transfer 25 line between slurry pump P-B-2 and pressure relief valve PSV-PB2-1 is self-draining. 26 RPP-RPT-42119, 242-A Evaporator PSV-PB2-1 Relief Valve – Functions and Requirements 27 Evaluation Document, provides additional description of pressure relief valve PSV-PB2-1. 28 29 Boundaries. The boundary of safety-significant pressure relief valve PSV-PB2-1 is the pressure 30 relief valve; the piping system components between the pressure relief valve branch connection 31 to the waste transfer line and the pressure relief valve; and the pressure relief valve discharge 32 piping system components. 33 34 Note: The piping system components between the pump discharge and the pressure relief valve 35
branch connection to the waste transfer line were conservatively not included in the 36 sizing and set pressure calculation (RPP-CALC-50347, 242A PSV-PB2-1 Pressure Relief 37 System Analysis) and, therefore, are not included in the safety-significant boundary. 38
39 Support Systems. The 242-A Building is required to protect pressure relief valve PSV-PB2-1 40 from damage due to ash, snow, and wind loads and, therefore, is designated safety significant 41 (see Section 4.4.7). 42 43
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4.4.6.3 Functional Requirements. The functional requirement of pressure relief valve 1 PSV-PB2-1 is to limit the slurry pump P-B-2 discharge pressure to ≤ 275 lb/in2 gauge. The 2 consequence analysis described in RPP-13750, Waste Transfer Leaks Technical Basis Document, 3 Attachment A14, concludes that the onsite toxicological consequence of a fine spray leak during 4 a waste transfer using slurry pump P-B-2 is less than PAC-3 if the pump discharge pressure is 5 limited to ≤ 150 m (490 ft.). For the bounding consequence assumption of a waste specific 6 gravity of 1.3, this equates to a pressure of ≤ 275 lb/in2 gauge. 7 8 There are no other functional/performance requirements derived from the hazard and accident 9 analyses, but additional requirements necessary to satisfy the safety function are developed in the 10 system evaluation (see Section 4.4.6.4). 11 12 4.4.6.4 System Evaluation. The system evaluation of pressure relief valve PSV-PB2-1 is 13 documented in RPP-RPT-42119. The evaluation identifies the functional/performance 14 requirements necessary for PSV-PB2-1 to perform its safety function. The evaluation also 15 identifies and evaluates potential failure modes of pressure relief valve PSV-PB2-1 considering 16 the conditions and events in which the safety function must be met. In addition, the evaluation 17 identifies and evaluates support systems whose function is required for pressure relief valve 18 PSV-PB2-1 to perform its safety function and interfaces whose failure could prevent PSV-PB2-1 19 from performing its safety function. The system evaluation satisfies DOE and TOC 20 requirements to ensure the reliable performance of safety-significant SSCs to meet the safety 21 function(s) determined from the hazard and accident analyses. 22 23 The primary functional/performance requirement is that pressure relief valve PSV-PB2-1 is sized 24 and has a set pressure that limits the slurry pump P-B-2 discharge pressure to ≤ 275 lb/in2 gauge. 25 The PSV-PB2-1 set pressure must consider the ASME code allowed 10% overpressure during a 26 pressure relieving event. 27 28 To account for an allowed 10% overpressure during a pressure relieving event, the pressure relief 29 valve set pressure must be ≤ 250 lb/in2 gauge (≤ 275 lb/in2 gauge/1.1). In addition, the inlet 30 piping pressure loss is 6 lb/in2 gauge. Therefore, the PSV-PB2-1 set pressure must be 31 ≤ 244 lb/in2 gauge (250 lb/in2 gauge – 6 lb/in2 gauge). 32 33 Pressure relief valve PSV-PB2-1 is sized (i.e., flow capacity) in accordance with ASME B31.3, 34 Process Piping, Section 322.6.3, which references Section VIII, Division 1 of the ASME Boiler 35 and Pressure Vessel Code (see RPP-CALC-50347). 36 37 Pressure relief valve PSV-PB2-1 is also designed for applicable waste transfer conditions, which 38 results in requirements on design pressure, design temperature, and materials of construction to 39 address compatibility issues associated with the chemical characteristics of the waste and 40 exposure to radiation. Functional/performance requirements including design pressure, design 41 temperature, and materials of construction are documented in RPP-RPT-42119, which also 42 demonstrates the design adequacy of PSV-PB2-1. 43 44
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4.4.6.4.1 Failure Mode Evaluation. RPP-RPT-42119 reviewed and evaluated pressure relief 1 valve PSV-PB2-1 for potential failure modes that could impact the ability to meet the safety 2 function. The evaluation results are summarized in Table 4.4.6-1. Where PSV-PB2-1 is not 3 designed to withstand the cause of the identified failure mode, the risk of the resulting hazard is 4 low, the failure mode is readily detected, or defense-in-depth features are provided. The results 5 of the evaluation are summarized below. 6 7
• A bellows is used to address slurry service. When a bellows is used, the pressure relief 8 valve bonnet vent plug is removed to allow air to enter and exit the bonnet. 9
10 • The safety-significant 242-A Building is identified as a supporting SSC. It is designed to 11
not fail due to ash, snow, and wind loads, and thus protects PSV-PB2-1 from damage due 12 to these loads. 13
14 • PSV-PB2-1 is not required to perform its safety function during or after a seismic event 15
(see Section 5.5.3.6, “Administrative Control 5.9.6 – Emergency Preparedness”). 16 17
• Damage to PSV-PB2-1 from readily detected events (i.e., fires) when waste transfers are 18 occurring will result in prompt shutdown of slurry pump P-B-2 if the damage is 19 determined to be significant enough to prevent PSV-PB2-1 from performing its safety 20 function. (Note: There is also a defense-in-depth feature to address this initiator. That 21 is, the fire protection requirements address fires). 22
23 • Damage to PSV-PB2-1 from readily detected events (i.e., seismic events, load handling 24
accidents, and fires) when waste transfers are not occurring will result in an inspection 25 and the necessary testing/repair/replacement prior to returning PSV-PB2-1 to service. 26 (Note: There are also defense-in-depth features to address some of these initiators. For 27 example, the hoisting and rigging program to prevent load handling accidents, and fire 28 protection requirements to address fires). 29
30 • For the following cause of damage to PSV-PB2-1 that may occur when waste transfers 31
are not occurring and may not be readily detected, a defense-in-depth feature was 32 identified and determined to acceptably control the risk of this potential failure mode. 33
34 - Damage due to a flammable gas deflagration: Flammable gas deflagrations in the 35
waste slurry transfer piping are unlikely based on the normal practice of flushing and 36 draining of waste transfer primary piping systems and the absence of ignition sources 37 (see Section 3.3.2.4.1). 38
39 Based on design life and operating conditions, the ability of pressure relief valve PSV-PB2-1 to 40 perform its safety function can degrade and periodic replacement is required. The following 41 shelf life and service life for PSV-PB2-1 has been established. 42 43
• A shelf life of 10 years from the date of ASME code certification testing (as reflected on 44 the code data sheet) and a service life of either five years from the date of installation 45
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(exposure to the tank headspace atmosphere) or two years from the date of first use for 1 transfer of waste, whichever comes first. 2
3 4.4.6.5 Controls (TSRs). Pressure relief valve PSV-PB2-1 is generally a passive design feature 4 whose characteristics are ensured through design, procurement, installation, startup testing, 5 configuration control, and quality conformance inspections. The activities performed under 6 these programs ensure that the safety function of pressure relief valve PSV-PB2-1 is preserved 7 and protect the design baseline from inadvertent change. 8 9 Safety-significant pressure relief valve PSV-PB2-1 is required to be operable when slurry pump 10 P-B-2 is active and not under administrative lock. 11 12 In-service inspections/tests are required to ensure the operability of pressure relief valve 13 PSV-PB2-1 by: 14 15
• Replacing PSV-PB2-1 if the shelf life or service life has been exceeded, whichever 16 occurs first. The shelf life and service life are as described in the system evaluation. 17
18 19 4.4.7 242-A Building 20 21 The 242-A Building is identified as a safety-significant support system (structure) for the 22 following: 23 24
• C-A-1 vessel flammable gas control system (Section 4.4.1) 25 • C-A-1 vessel waste high level control system (Section 4.4.2) 26 • C-A-1 vessel seismic dump system (Section 4.4.3) 27 • E-A-1 reboiler (Section 4.4.4) 28 • Backflow prevention devices (PSV-RW-3 and BFP-RW-11) (Section 4.4.5) 29 • Pressure relief valve PSV-PB2-1 (Section 4.4.6) 30
31 Note: The 242-A Building is also identified as a safety-significant support system for slurry line 32
vacuum breaker PSV-CA1-4, which is a safety-significant SSC for tank farms (See 33 RPP-13033, Tank Farms Documented Safety Analysis, Section 4.4.6, “242-A Evaporator 34 Slurry Line Vacuum Breaker PSV-CA1-4”). 35
36 4.4.7.1 Safety Function(s). The safety functions for the 242-A Building are: 37 38
• For the 242-A Building (Area 1, Area 2, and Area 3), to maintain structural integrity for 39 design basis wind loads, snow loads, and ashfall loads. Maintaining structural integrity 40 for design basis wind loads, snow loads, and ashfall loads prevents flammable gas 41 accidents or waste leaks and misroutes due to impacts from building (2 over 1) failure. 42 Maintaining structural integrity for design basis wind loads, snow loads, and ashfall loads 43 also prevents loss of the safety function for safety-significant SSCs located in the 242-A 44 Building due to building (2 over 1) failure. 45
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• For the 242-A Building (Area 1, Area 2, and other internal structures), to maintain 1 structural integrity for design basis earthquake (seismic) loads. Maintaining structural 2 integrity for design basis earthquake (seismic) loads prevents loss of the C-A-1 vessel 3 seismic dump system safety function due to building and other internal structure 4 (2 over 1) failure. 5
6 4.4.7.2 System Description. The 242-A Building (sometimes referred to as the main building) 7 is a reinforced concrete structure that contains two processing areas, Area 1 and Area 2. Area 1 8 contains the evaporator and condenser rooms. Area 2 contains the pump room; aqueous makeup 9 (AMU) room; heating, ventilation, and air conditioning (HVAC) room; and load-out and 10 hot-equipment storage room. 11 12 The 242-A Building also includes an administration building (Area 3) which contains personnel 13 support areas (not including the control room and associated electrical room, which are in the 14 242-AB Building). The Area 3 building is a reinforced 8-in thick concrete masonry unit (CMU) 15 bearing wall structure, supported on a continuous strip footing. The roof is a light weight metal 16 deck roof supported by steel beams that bear on the CMU walls. The Area 3 building shares the 17 east wall of the main building (Areas 1 and 2) but is structurally isolated from Area 1 and Area 2 18 as well as the 242-AB Building. 19 20 Section 2.4, “242-A Evaporator Structures,” contains additional information about the 242-A 21 Building structure. 22 23 Boundaries. The safety-significant 242-A Building consists of processing Area 1, Area 2, and 24 Area 3; and the following other Area 1 and 2 internal structures: 25 26
29 Support Systems. There are no safety-significant support systems identified for the 242-A 30 Building. 31 32 4.4.7.3 Functional Requirements. The functional requirements for the 242-A Building are: 33 34
1. For the 242-A Building (Area 1, Area 2, and Area 3), to meet PC-2 for high winds, snow, 35 and ashfall. 36
37 2. For the 242-A Building (Area 1, Area 2, and other internal structures), to meet PC-2 for 38
seismic events. 39 40 There are no other functional/performance requirements derived from the hazard and accident 41 analyses or the system evaluation in Section 4.4.7.4. 42 43 4.4.7.4 System Evaluation. The system evaluation of the 242-A Building is documented in 44 RPP-RPT-52517, 242-A Evaporator Facility Assessment for Performance Category 2 Natural 45 Phenomena Hazards. 46 47
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The first functional requirement is for the 242-A Building (Area 1, Area 2, and Area 3) to meet 1 PC-2 requirements for high winds, snow, and ashfall. PC-2 is assigned based on 2 DOE-STD-1021-93, Natural Phenomena Hazards Performance Categorization Guidelines for 3 Structures, Systems, and Components, as the protected SSC are classified as safety significant. 4 5 RPP-RPT-52517 provides the technical basis for concluding that the 242-A Building meets PC-2 6 requirements for wind load, snow load, and ash load based on a comparison and evaluation of 7 current loading requirements for PC-2 versus the requirements and loadings used for design of 8 the building. 9 10 The second functional requirement is for the 242-A Building (Area 1, Area 2, and other internal 11 structures) to meet PC-2 for seismic events. RPP-RPT-52517 provides the technical basis for 12 concluding that the 242-A Building meets PC-2 requirements for seismic events based on a 13 comparison and evaluation of current loading requirements for PC-2 versus the requirements and 14 loadings used for design of the building. 15 16 The evaluation of other Area 1 and Area 2 internal structures is documented in the design 17 evaluation of the C-A-1 vessel seismic dump system. That is, internal structures that could 18 interact with the C-A-1 vessel seismic dump system components and prevent the C-A-1 vessel 19 seismic dump system from performing its safety function are identified and evaluated in 20 RPP-RPT-52517, RPP-TE-56679, Seismic 2 over 1 Evaluation for HS-CA1-1 – 242-A 21 Evaporator Emergency Stop Button, and 43583-029-SUB-020-002, Seismic Interaction 22 Evaluation – 242-A Evaporator DSA Upgrades Design Project. Possible interactions are 23 addressed by component location (the component is installed in a location where interaction is 24 precluded) or an evaluation of other internal structures (nearby equipment) for PC-2 25 requirements. These other internal structures include the following. 26 27
30 4.4.7.5 Controls (TSRs). The 242-A Building and other internal structures are passive design 31 features whose characteristics are ensured through configuration control requirements. 32 33 The 242-A Building and other internal structures (i.e., pump room cover blocks and E-C-1 34 condenser supports) are required to be operable in the Operation Mode. In addition, the 242-A 35 Building is required to be operable in the Limited Waste Mode (see Section 5.4.1 for mode 36 definitions). 37 38 39 4.5 TSR SPECIFIC ADMINISTRATIVE CONTROLS 40 41 42 4.5.1 Flammable Gas Controls for Waste Feed Transfer Piping, Waste Slurry 43
Transfer Piping, and C-A-1 Vessel Drain (Dump) Piping 44 45 4.5.1.1 Safety Function. The safety function of the flammable gas controls for waste feed 46 transfer piping, waste slurry transfer piping, and C-A-1 vessel drain (dump) piping is to protect 47
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the facility worker from a flammable gas deflagration due to the accumulation and ignition of 1 flammable gases in waste feed transfer piping, waste slurry transfer piping, or C-A-1 vessel drain 2 (dump) piping. 3 4 This control is identified as a SAC for a flammable gas deflagration involving flammable gas 5 generated in the waste feed transfer piping, waste slurry transfer piping, and C-A-1 vessel drain 6 (dump) piping (see Section 3.3.2.4.1). The ignition of flammable gas is dependent upon the 7 presence of a concentration in the flammable range, and the presence of an ignition source. In 8 this case, the ignition source may be introduced by the operation of installed equipment, or the 9 performance of intrusive work activities (e.g., activities that have the potential to release 10 flammable gas from the piping of concern, or introduce an ignition source into the piping of 11 concern). There is no practical engineered control to protect facility workers from flammable 12 gas hazards in waste feed transfer piping, waste slurry transfer piping, and C-A-1 vessel drain 13 (dump) piping; the only practical means for implementing ignition controls is a SAC. 14 15 4.5.1.2 SAC Description. Based on the hazard and accident analyses in Section 3.3.2.4.1, the 16 accumulation of flammable gases generated by residual waste in waste feed transfer piping, 17 waste slurry transfer piping, and C-A-1 vessel drain (dump) piping could exceed the LFL. If a 18 mixture in the flammable range is ignited while workers are in the evaporator room (Room A), 19 pump room (Room B), load-out and hot equipment storage room (Room F), or loading room 20 (Room G) the resulting explosion could cause a significant facility worker hazard. The source of 21 ignition for this event may be caused by installed equipment or by manned work activities; the 22 specific work activities of concern are those intrusive work activities that have the potential to 23 release flammable gas from the piping of concern, or introduce an ignition source into the piping 24 of concern. Therefore, the SAC is applicable to installed equipment within waste feed transfer 25 piping, waste slurry transfer piping, and C-A-1 vessel drain (dump) piping, and to manned work 26 activities involving waste feed transfer piping, waste slurry transfer piping, and C-A-1 vessel 27 drain (dump) piping. 28 29 The SAC requires that installed equipment have been verified to meet ignition controls. The 30 SAC also requires that prior to manned work activities, an approved evaluation shall have been 31 verified to demonstrate that steady-state flammable gas generation cannot result in a flammable 32 gas concentration of > 25% of the LFL in the location of concern, or that ignition controls are 33 implemented. Ignition control requirements are determined in accordance with Administrative 34 Control (AC) Key Element Ignition Controls (see Section 5.5.3.2). 35 36 4.5.1.3 Functional Requirements. The functional requirement of the SAC Flammable Gas 37 Controls for Waste Feed Transfer Piping, Waste Slurry Transfer Piping, and C-A-1 Vessel Drain 38 (Dump) Piping are: 39 40
• For installed equipment: 41 42
- Control potential ignition sources associated with installed equipment installed within 43 waste feed transfer piping, waste slurry transfer piping, or C-A-1 vessel drain (dump) 44 piping. 45
46
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• For manned work activities: 1 2
- Ensure the concentration of flammable gases from steady-state generation in the 3 location of concern is ≤ 25% of the LFL, or 4
5 - Control potential ignition sources associated with activity work practices, equipment, 6
and materials. 7 8 Ignition control requirements are determined in accordance with AC Key Element Ignition 9 Controls (see Section 5.5.3.2). 10 11 4.5.1.4 SAC Evaluation. The SAC is applicable to (1) equipment installed within waste feed 12 transfer piping, waste slurry transfer piping, and C-A-1 vessel drain (dump) piping; and 13 (2) manned work activities involving waste feed transfer piping, waste slurry transfer piping, and 14 C-A-1 vessel drain (dump) piping. 15 16 In order to control potential ignition sources associated with installed equipment, the SAC 17 requires that installed equipment has been verified to meet ignition controls under AC Key 18 Element Ignition Controls (AC 5.9.2). The applicability of the SAC is limited to equipment 19 installed within waste feed transfer piping, waste slurry transfer piping, and C-A-1 vessel drain 20 (dump) piping. The requirement that equipment has been verified to be compliant ensures that 21 the determination of ignition controls and evaluation of compliance is in place for installed 22 equipment. The process for determination and evaluation of ignition controls for installed 23 equipment under AC 5.9.2 is described in Section 5.5.3.2. 24 25 In order to ensure control of potential ignition sources associated with manned work activities 26 involving waste feed transfer piping, waste slurry transfer piping, or C-A-1 vessel drain (dump) 27 piping, the SAC requires implementation of ignition controls for manned work activities. 28 Alternatively, the SAC allows verification prior to the manned work activity that an approved 29 evaluation demonstrates that steady-state flammable gas generation cannot result in a flammable 30 gas concentration of > 25% of the LFL in the location of concern. If the flammable gas 31 concentration is ≤ 25% of the LFL, ignition controls are not necessary for explosion prevention, 32 as the gas is not in the flammable range. The use of 25% of the LFL as the control point 33 provides a margin of safety, and alignment with applicable codes and standards. Ensuring that 34 definition and implementation of ignition controls or verification of the applicability of an 35 approved evaluation prior to the start of manned work activities ensures that the appropriate 36 controls are in place to protect personnel. The process for determination and evaluation of 37 ignition controls for manned work activities involving waste feed transfer piping, waste slurry 38 transfer piping, or C-A-1 vessel drain (dump) piping is defined by AC Key Element Ignition 39 Controls (AC 5.9.2), as described in Section 5.5.3.2. 40 41 The SAC allows ignition controls for a manned work activity to be discontinued when 42 monitoring has verified that the steady-state flammable gas concentration is ≤ 25% of the LFL in 43 the location of concern. The location of concern is defined as within the waste feed transfer 44 piping, waste slurry transfer piping, or C-A-1 vessel drain (dump) piping (as applicable to the 45 manned work activity being performed); this choice of location is conservative, as a 46
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concentration of ≤ 25% of the LFL cannot result in a concentration of > 25% of the LFL in the 1 occupied area. 2 3 Flammable gas monitoring is performed by an industrial hygiene technician (IHT) using a 4 calibrated portable combustible gas monitor (CGM). The IHTs are trained on the proper use of 5 the CGM. Retraining is provided every two years to reinforce the proper way to take a sample. 6 The CGM is an instrument calibrated in accordance with the requirements of TFC-PLN-02, 7 Quality Assurance Program Description. The sample is drawn from a location that meets the 8 requirements of TFC-ESHQ-FP-STD-05, Flammable Gas Monitoring, to ensure that the sample 9 is representative of the vapor space inside the piping. 10 11 4.5.1.5 Controls (TSRs). Flammable Gas Controls for Waste Feed Transfer Piping, Waste 12 Slurry Transfer Piping, and C-A-1 Vessel Drain (Dump) Piping is a SAC that is implemented as 13 a directed action AC. 14 15 The SAC applies to: 16 17
• Equipment installed within waste feed transfer piping, waste slurry transfer piping, or 18 C-A-1 vessel drain (dump) piping. 19
20 • Manned work activities involving waste feed transfer piping, waste slurry transfer piping, 21
or C-A-1 vessel drain (dump) piping. 22 23 The SAC requirements are: 24 25
A. Installed Equipment 26 27
1. Installed equipment shall have been VERIFIED to meet ignition controls. 28 29
AND 30 31
2. Ignition control requirements shall be determined in accordance with AC Key 32 Element Ignition Controls (see AC 5.9.2). 33
34 B. Manned Work Activities 35
36 1. Prior to manned work activities, an approved evaluation shall have been VERIFIED 37
to demonstrate that steady-state flammable gas generation cannot result in a 38 flammable gas concentration of > 25% of the LFL in the location of concern. 39
40 OR 41
42 2. a. Ignition controls shall be implemented for manned work activities. 43
44 AND 45
46
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2. b. Ignition control requirements shall be determined in accordance with AC Key 1 Element Ignition Controls (see AC 5.9.2). 2
3 AND 4
5 2. c. Ignition control requirements for a manned work activity may be discontinued 6
when monitoring has VERIFIED that steady-state flammable gas concentration is 7 ≤ 25% of the LFL in the location of concern. 8
9 4.5.2 Evaporator and Pump Room Access and Pump Room Cover Block Control 10 11 4.5.2.1 Safety Function. The safety function of the SAC Evaporator and Pump Room Access 12 and Pump Room Cover Block Control is to restrict access to the pump room and evaporator 13 room and require the pump room cover blocks to be in place when waste is in the C-A-1 vessel, 14 waste could be misrouted to the 242-A Evaporator from tank farms, or when the pump room 15 sump steam jet pump J-B-1 is not under administrative lock. Controlling access to the pump 16 room and evaporator room and controlling the removal of the pump room cover blocks protects 17 facility workers from waste leaks (i.e., chemical burns caused by wetting spray/jet/stream leaks) 18 and direct radiation hazards. 19 20 This control is identified as a SAC for waste leaks and misroutes (see Section 3.3.2.4.3). The 21 SAC controls access to the evaporator and pump rooms by authorizing the release of keys to 22 open the locked doors that provide access to the evaporator and pump rooms. Engineered 23 controls (i.e., locked doors) prevent unauthorized access to the evaporator and pump rooms. The 24 SAC also controls the removal of the pump room cover blocks. The 242-A overhead crane is 25 required to remove the pump room cover blocks. The SAC ensures that required conditions are 26 satisfied prior to unlocking the access doors to the evaporator and pump rooms or removing the 27 pump room cover blocks. There are no practical engineering controls that could perform the 28 SAC safety function. 29 30 4.5.2.2 SAC Description. The SAC has two parts: 31 32
• Controlling personnel access to the evaporator and pump rooms. 33 • Controlling the removal of the pump room cover blocks. 34
35 Access to the evaporator and pump rooms is restricted by locks on the two evaporator room 36 doors that provide the only personnel access to the evaporator and pump rooms. 37 38 Personnel access to the evaporator and pump rooms is, however, required periodically to perform 39 maintenance. The pump room cover blocks are only removed to support maintenance in the 40 evaporator and pump rooms. Removal of the pump room cover blocks requires use of the 242-A 41 overhead crane. 42 43 The SAC is implemented through TFC-OPS-OPER-C-04, Access and Key Control for Operation 44 Facilities, which controls personnel access to the evaporator and pump rooms, and TO-600-140, 45 Operate 242-A Overhead Crane, which controls removal of the pump room cover blocks. The 46 evaporator and pump rooms are controlled as high radiation areas. Shift manager authorization 47
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is required to obtain the 242-A high radiation area keys for the two doors to the evaporator room 1 (outer door 108 in the airlock at grade and outer door 402 in the airlock at the 40 ft.-6 in. level). 2 TFC-OPS-OPER-C-04 requires two responsible and knowledgeable workers (i.e., 242-A Shift 3 Manager, Field Worker Supervisor, or operator) to verify the following conditions prior to 4 issuing the 242-A keys to the evaporator room. 5 6
• Verify that the 242-A Evaporator is in the Shutdown Mode. 7 8
• Verify that slurry lines SL-167 and SL-168 are not physically connected to an active 9 waste transfer pump that is not under administrative lock. 10
11 • Verify that the tank farms waste transfer pump (feed pump) 241-AW-P-102-1 and 242-A 12
Evaporator waste transfer pump (pump room sump steam jet pump) J-B-1 are under 13 administrative lock. 14
15 TO-600-140 requires verification by two responsible and knowledgeable workers (i.e., 242-A 16 Shift Manager, Field Work Supervisor, or operator) of the above conditions prior to removing 17 pump room cover blocks. 18 19 When the 242-A Evaporator is in the Shutdown Mode, the C-A-1 vessel is empty, except for 20 water, antifoaming agents, process condensate, inhibited water, etc., and there is no facility 21 worker chemical burn hazard from a waste leak and no direct radiation hazard. The definition of 22 “empty of waste” as applied to the C-A-1 vessel is provided in Section 5.4.1. 23 24 Waste misroutes to the 242-A Evaporator from tank farms are prevented by ensuring that the 25 tank farms waste transfer pump (feed pump) 241-AW-P-102-1 is under administrative lock and 26 that slurry lines SL-167 and SL-168 are not physically connected to an active waste transfer 27 pump that is not under administrative lock. 28 29 Slurry lines SL-167 and SL-168 are used to transfer waste from the 242-A Evaporator to a 30 receiver tank in tank farms, but waste could be misrouted from tank farms to the 242-A 31 Evaporator through these lines. The definition of “under administrative lock” is provided in 32 Section 3.3.2.4.3. TFC-OPS-OPER-C-22, Control and Use of Administrative Locks, describes 33 the control and use of administrative locks. The definitions of “active,” “waste transfer pump,” 34 and “physically connected” are also provided in Section 3.3.2.4.3. (Note: Physical 35 disconnection of slurry lines SL-167 and SL-168 is normally implemented by two tank farms 36 safety-significant waste transfer system isolation valves, independently verified to be in the 37 closed or block flow position. However, this is not the only means of satisfying the requirement 38 that slurry lines SL-167 and SL-168 are not physically connected to an active waste transfer 39 pump that is not under administrative lock.) 40 41 Waste transfers from the pump room sump are prevented by placing pump room sump steam jet 42 pump J-B-1 under administrative lock in accordance with TFC-OPS-OPER-C-22. 43 44
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4.5.2.3 Functional Requirements. The SAC Evaporator and Pump Room Access and Pump 1 Room Cover Block Control shall ensure that personnel in the evaporator and pump rooms and 2 pump room cover block removal are prevented except when: 3 4
• The 242-A Evaporator is in the Shutdown Mode. 5 6
AND 7 8
• Slurry lines SL-167 and SL-168 are physically disconnected from an active waste transfer 9 pump not under administrative lock. 10
11 AND 12
13 • Tank farms waste transfer pump (feed pump) 241-AW-P-102-1 and 242-A Evaporator 14
waste transfer pump (pump room sump steam jet pump) J-B-1 are under administrative 15 lock. 16
17 4.5.2.4 SAC Evaluation. To protect facility workers from chemical burn hazards and direct 18 radiation exposure from waste leaks and misroutes, the two evaporator room doors that allow 19 personnel access to the evaporator and pump rooms (outer door 108 in the airlock at grade and 20 outer door 402 in the airlock at the 40 ft-6 in. level) are closed and locked, and the pump room 21 cover blocks (which require the 242-A overhead crane to remove) are in place. This 22 configuration is controlled by procedures TFC-OPS-OPER-C-04 and TO-600-140, which ensure 23 that personnel access to the evaporator and pump rooms and the removal of the pump room 24 cover blocks are not allowed except when: 25 26
• The 242-A Evaporator is in the Shutdown Mode. 27 28
• Slurry lines SL-167 and SL-168 are physically disconnected from an active waste transfer 29 pump not under administrative lock. 30
31 • Waste feed transfer pump (feed pump) 241-AW-P-102-1 and 242-A Evaporator waste 32
transfer pump (pump room sump steam jet pump) J-B-1 are under administrative lock. 33 34 Verification of the above conditions prior to allowing personnel access to the evaporator and 35 pump rooms ensures that facility workers in the evaporator and pump rooms are protected from 36 chemical burn and direct radiation hazards from waste in the C-A-1 vessel, from the misroute of 37 waste to the 242-A Evaporator from tank farms, and from waste transfers with the pump room 38 sump steam jet pump J-B-1. The above verifications prior to removal of the pump room cover 39 blocks protect facility workers who may be above the pump room from direct radiation hazards. 40 41 TFC-OPS-OPER-C-04 and TO-600-140 both require verification by two responsible and 42 knowledgeable workers (i.e., 242-A Shift Manager, Field Work Supervisor, or operator). 43 TFC-OPS-OPER-C-04 also requires that the 242-A high radiation area keys for the two doors to 44 the evaporator room (outer door 108 in the airlock at grade and outer door 402 in the airlock at 45 the 40 ft-6 in. level) are stored in a security approved storage box/cabinet and locking device 46
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designated for high radiation area keys only. In addition, the keys are labeled/tagged to clearly 1 identify them as high radiation area keys. The evaporator room door locks are not classified as 2 safety significant since the only function is to prevent unauthorized personnel access. The 3 existing door locks are Grade 1 mortise locksets (meet ANSI/BHMA A156.13, Mortise Locks 4 and Latches Series 1000, Grade 1) suitable for high-traffic commercial, institutional, industrial, 5 and government applications. Patented key control provides protection against the unauthorized 6 duplication of keys. These locks are sufficient to prevent unauthorized personnel access, and the 7 doors also clearly warn that the evaporator and pump rooms are high radiation areas requiring 8 authorization to enter. 9 10 Given the above, this control provides adequate assurance that facility workers are protected 11 from potential waste leaks in the evaporator and pump rooms and from the misroute waste 12 (waste leak or direct radiation exposure in an unintended location). 13 14 4.5.2.5 Controls (TSRs). Evaporator and Pump Room Access and Pump Room Cover Block 15 Control is a SAC that is implemented as a directed action AC with the following requirement. 16 17
The evaporator room doors (outer door 108 in the airlock at grade and outer door 402 in the 18 airlock at the 40 ft-6 in. level) shall be closed and locked and the pump room cover blocks 19 shall be in place except when the following conditions are met. 20 21
• The 242-A Evaporator is in the Shutdown Mode. 22 23
AND 24 25
• The slurry lines SL-167 and SL-168 are not physically connected to an active waste 26 transfer pump not under administrative lock. 27
28 AND 29
30 • Tank farms waste transfer pump (feed pump) 241-AW-P-102-1 and 242-A 31
Evaporator waste transfer pump (pump room sump steam jet pump) J-B-1 are under 32 administrative lock. 33
34 4.5.3 Evaporator and Pump Room Transient Combustible Material Controls 35 36 4.5.3.1 Safety Function. The safety function of evaporator and pump room transient 37 combustible material control is to prevent unsafe failures of feed valve HV-CA1-1 and dump 38 valves HV-CA1-7 and HV-CA1-9 due to fires. 39 40 This control is identified as a SAC to protect feed valve HV-CA1-1 (and its actuator), which is 41 located in the pump room, and is included in the safety-significant C-A-1 vessel flammable gas 42 control system (see Section 4.4.1), the safety-significant C-A-1 vessel waste high level control 43 system (see Section 4.4.2), and the safety-significant C-A-1 vessel seismic dump system (see 44 Section 4.4.3). This SAC also protects dump valves HV-CA1-7 and HV-CA1-9, which are 45 located in the evaporator room, and are included in the safety-significant C-A-1 vessel 46 flammable gas control system and the safety-significant C-A-1 vessel waste high level control 47
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system. The SAC eliminates or limits the fire that can occur in the evaporator room and pump 1 room, and there is no practical engineered control to protect these valves from fires. That is, 2 there is no practical engineered control to insulate these valves from uncontrolled fires, and no 3 practical fire detection and prevention system that can control the timing and size of fires to 4 prevent unsafe valve failures. 5 6 4.5.3.2 SAC Description. The SAC controls transient combustible materials within the 7 evaporator room and the pump room to limit feed valve HV-CA1-1 and dump valves HV-CA1-7 8 and HV-CA1-9 temperatures due to fires based on fire hazard analysis in HNF-SD-WM-FHA-024, 9 Fire Hazards Analysis for the Evaporator Facility (242-A), and supporting analysis in 10 RPP-CALC-57394, Hazard Analysis of the Fire Exposure to Critical Valves for the 242-A 11 Evaporator Building. Transient combustible materials are any combustible materials (e.g., wood, 12 cardboard, cotton cloth, paper, rubber/plastic) that are not permanently installed and not stored in 13 an approved tool container. Permanently installed combustible materials (fixed combustible 14 materials) are evaluated in RPP-CALC-57394 which concludes that the fixed combustible 15 materials would not support a damaging fire, and, therefore, are excluded from these controls. 16 Items inside of a closed and latched approved tool container are not available to burn, and, 17 therefore, are excluded from these controls. The SAC controls the following. 18 19
1. The total heat of combustion of transient combustible materials within the evaporator 20 room shall be < 400,000 BTU. 21
22 2. The total heat of combustion of transient combustible materials within the pump room 23
shall be < 56,000 BTU. 24 25
3. No transient combustible liquid or transient flammable liquid shall be present in the 26 evaporator room or pump room, including within an approved tool container. 27
28 4. No transient combustible materials shall be present within the following zones in the 29
evaporator room and pump room. 30 31
a. A rectangular prism with side dimensions of at least 18 ft centered on dump valve 32 HV-CA1-7 or up to the evaporator room wall, and with a vertical dimension from the 33 floor to at least 9 ft above the valve. 34
35 b. A rectangular prism with side dimensions of at least 14 ft centered on dump valve 36
HV-CA1-9 or up to the evaporator room wall, and with a vertical dimension from the 37 floor to at least 7 ft above the valve. 38
39 c. A rectangular prism with side dimensions of at least 12 ft centered on feed valve 40
HV-CA1-1 or up to the pump room wall, and with a vertical dimension from the floor 41 to the bottom of the pump room cover blocks. 42
43 The amount and location of transient combustible materials in the evaporator room and pump 44 room are verified by performing an inspection of the evaporator room and pump room using 45 procedure TO-600-300, Perform Closeout Inspection in Evaporator Room and Pump Room. The 46 total heat of combustion of transient combustible materials in the evaporator room and in the 47
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pump room is determined and compared to the limits in a calculation documented in accordance 1 with TFC-ENG-DESIGN-C-10, Engineering Calculations. 2 3 Note: The transient combustible materials in the evaporator room include the transient 4 combustible materials in the two airlocks, one at grade and one at 40 ft.-6 in., which allow 5 personnel access to the evaporator room from the building exterior. 6 7 The areas of the evaporator room or pump room that need to be inspected may be limited as 8 determined by a shift manager (e.g., by a review that work performed since the last inspection 9 did not access the upper elevations of the room) and recorded on the evaporator room and pump 10 room combustible material inventory status log. Any limitations on areas to be inspected are 11 reviewed by a second shift manager. 12 13 The inspection is performed by an operator and a fire protection engineer (inspectors) and 14 documents a description of the transient combustible materials including estimated weight or 15 dimensions and materials of construction as ordinary combustible materials (e.g., wood, 16 cardboard, cotton cloth, paper) or rubber/plastic. One inspector identifies and describes each 17 transient combustible material item and the second inspector provides concurrent verification. 18 (Note: Concurrent verification is the act of checking by qualified personnel that a given 19 operation or field calculation conforms to established criteria, as well as checking a component 20 position, without the requirement that the check be at a separate occasion or independent of 21 activities related to establishing the components position.) Mass is estimated qualitatively and 22 rounded to a conservatively high value. If estimated dimensions are recorded rather than 23 estimated mass, one inspector obtains the dimensions (e.g., using a measuring tape or measuring 24 scale) and the second inspector provides concurrent verification. Optionally, a picture can be 25 recorded of the object along with the dimensions shown on a measuring tape or measuring scale. 26 The material of construction is determined by the fire protection engineer. (Note: Items within 27 an approved tool container that is closed and latched are not included as transient combustible 28 materials, provided the tool container’s top, bottom, and sides are constructed of not less than 29 16-gauge steel, with continuous welds, and the tool container has been reviewed and approved 30 by a fire protection engineer). The information for each transient combustible material item is 31 recorded on the evaporator room and pump room combustible material inventory status log. 32 33 An inspector verifies that there are no transient combustible liquid or transient flammable liquid 34 present in the evaporator room or pump room, including within an approved tool container, and 35 the second inspector provides concurrent verification. The status is recorded on the evaporator 36 room and pump room combustible material inventory status log. 37 38 An inspector verifies that the tool container is closed and latched, and the second inspector 39 provides concurrent verification. The status is recorded on the evaporator room and pump room 40 combustible material inventory status log. 41 42 An inspector verifies that there are no transient combustible materials within each combustible 43 material free zone, and the second inspector provides concurrent verification. The status is 44 recorded on the pump room and evaporator room combustible inventory status log. 45 46
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Both the operator and the fire protection engineer sign the evaporator room and pump room 1 combustible material inventory status log. 2 3 The total heat of combustion in the evaporator room is determined for the combustible material 4 inventory recorded on the status log by assigning a heat of combustion of 8,000 BTU/lb for 5 ordinary combustible materials and a heat of combustion of 20,000 BTU/lb for rubber/plastics, 6 and summing over all items in the evaporator room. The total heat of combustion in the pump 7 room is determined similarly. The calculation is performed in accordance with 8 TFC-ENG-DESIGN-C-10, which requires that a second engineer review the calculation. 9 10 4.5.3.3 Functional Requirements. The SAC Evaporator and Pump Room Transient 11 Combustible Material Controls shall limit feed valve HV-CA1-1 and dump valves HV-CA1-7 12 and HV-CA1-9 temperatures due to fires to within the valves’ temperature ratings, which are as 13 follows. 14 15
19 4.5.3.4 SAC Evaluation. SAC Evaporator and Pump Room Transient Combustible Material 20 Controls controls transient combustible materials within the evaporator room and the pump room 21 to limit feed valve HV-CA1-1 and dump valves HV-CA1-7 and HV-CA1-9 temperatures due to 22 fires. The controls are based on fire hazard analysis in HNF-SD-WM-FHA-024 and supporting 23 analysis RPP-CALC-57394. The amount and location of transient combustibles in the 24 evaporator room and pump room are verified by performing an inspection of the evaporator 25 room and pump room using procedure TO-600-300. Access locations are available to perform a 26 thorough visual inspection of locations where transient combustible material might be located. 27 The side dimensions of the combustible material free zone for HV-CA1-1 are conservatively 28 implemented as the entire floor area of the pump room. The bottom of the cover blocks in the 29 pump room is a clear indicator of the height of the zone in the pump room. The side dimensions 30 of the combustible material free zones for HV-CA1-7 and HV-CA1-9 are conservatively 31 implemented as the entire floor area of the evaporator room with the exception of the tool board 32 on the north wall of evaporator, which is outside of the analyzed zones. The height of the zones 33 in the evaporator room are conservatively defined as extending vertically to the bottom of the 34 Elevation 30’ 6” platform. Concurrent verification is provided for each transient combustible 35 material description, estimated mass or dimensions, and location. Concurrent verification 36 provides assurance that the status of the transient combustible material is accurate. The 37 evaporator room and pump room are high radiation and airborne areas and entry requires high 38 risk work planning. Therefore, independent verification is not practical or consistent with as low 39 as reasonably achievable (ALARA) practices. The material of construction of transient 40 combustible materials is determined by the fire protection engineer who has expertise to 41 differentiate ordinary combustible materials from rubber/plastic items. 42 43 Entry into the evaporator room and pump room is controlled (requires high risk work planning). 44 SAC Evaporator and Pump Room Transient Combustible Material Control is performed after all 45 work activities that require entry into the evaporator room or pump room have been completed 46 prior to entering the Operation Mode, with the exception of performing TO-600-220, 242-A 47
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Evaporator Adjust PB-1 Seal Water Needle Valve. TO-600-220 does not require any combustible 1 material items used during TO-600-220 to be left in the evaporator room or pump room and any 2 items used during TO-600-220 (e.g., sample wipes, PPE, screw driver) that might inadvertently 3 be left in the evaporator room or pump room are minor articles of combustible materials. Minor 4 articles of combustible materials are evaluated in RPP-CALC-57394 and do not present a 5 sufficient hazard to threaten the valves’ temperature ratings. During Operation Mode, no access 6 to the evaporator room or pump room is allowed (see Section 4.5.2). 7 8 Verification of the above conditions prior to entering Operation Mode provides assurance that 9 feed valve HV-CA1-1 and dump valves HV-CA1-7 and HV-CA1-9 temperatures due to fires 10 will be within the valves’ temperature ratings. 11 12 Given the above, this control provides adequate assurance that unsafe failures of feed valve 13 HV-CA1-1 and dump valves HV-CA1-7 and HV-CA1-9 due to fires are prevented. 14 15 4.5.3.5 Controls (TSRs). Evaporator and Pump Room Transient Combustible Material Control 16 is a SAC that is implemented as a directed action AC. The SAC is applicable in Operation 17 Mode. The SAC requirements are: 18 19
1. The total heat of combustion of transient combustible materials within the evaporator 20 room shall be < 400,000 BTU. 21
22 2. The total heat of combustion of transient combustible materials within the pump room 23
shall be < 56,000 BTU. 24 25
3. No transient combustible liquid or transient flammable liquid shall be present in the 26 evaporator room or pump room, including within an approved tool container. 27
28 4. No transient combustible materials shall be present within the following zones in the 29
evaporator room and pump room. 30 31
a. A rectangular prism with side dimensions of at least 18 ft centered on dump valve 32 HV-CA1-7 or up to the evaporator room wall, and with a vertical dimension from the 33 floor to at least 9 ft above the valve. 34
35 b. A rectangular prism with side dimensions of at least 14 ft centered on dump valve 36
HV-CA1-9 or up to the evaporator room wall, and with a vertical dimension from the 37 floor to at least 7 ft above the valve. 38
39 c. A rectangular prism with side dimensions of at least 12 ft centered on feed valve HV-40
CA1-1 or up to the pump room wall, and with a vertical dimension from the floor to 41 the bottom of the pump room cover blocks. 42
43 44
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4.6 REFERENCES 1 2 10 CFR 830, “Nuclear Safety Management,” Office of the Federal Register (FR 1810, Vol. 66, 3
9 ANSI/BMHA A156.13, Mortise Locks and Latches Series 1000, American National Standards 10
Institute/Builder’s Hardware Manufacturers Association, New York, New York. 11 12 API 570, Piping Inspection Code: In-service Inspection, Rating, Repair, and Alteration of Piping 13
Systems, American Petroleum Institute, Washington, D.C. 14 15 ASCE 7, 2005, Minimum Design Loads for Buildings and Other Structures, American Society of 16
Civil Engineers, Reston, Virginia. 17 18 ASME B31.1-1973, Power Piping, American Society of Mechanical Engineers, New York, 19
New York. 20 21 ASME B31.3, Process Piping, American Society of Mechanical Engineers, New York, 22
New York. 23 24 ASME Boiler & Pressure Vessel Code, Section III, Division I, Rules for Construction of Nuclear 25
Facility Components, American Society of Mechanical Engineers, New York, New York. 26 27 DOE G 421.1-2, 2001, Implementation Guide for Use in Developing Documented Safety 28
Analyses to Meet Subpart B of 10 CFR 830, U.S. Department of Energy, 29 Washington D.C. 30
for Structures, Systems, and Components, U.S. Department of Energy, Washington, D.C. 33 34 DOE-STD-1186-2004, 2004, Specific Administrative Controls, U.S. Department of Energy, 35
Washington, D.C. 36 37 DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor 38
Nuclear Facility Documented Safety Analyses, Change Notice No. 3, U.S. Department of 39 Energy, Washington, D.C. 40
41 HNF-SD-WM-FHA-024, 2017, Fire Hazard Analysis for the Evaporator Facility (242-A), 42
Rev. 8C, Washington River Protection Solutions LLC, Richland, Washington. 43 44 NFPA 69, 2002, Standard on Explosion Prevention Systems, National Fire Protection 45
Association, Quincy, Massachusetts. 46 47
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RPP-13033, Tank Farms Documented Safety Analysis, as amended, Washington River Protection 1 Solutions LLC, Richland, Washington. 2
3 RPP-13750, 2013, Waste Transfer Leaks Technical Basis Document, Rev. 40, Washington River 4
Protection Solutions LLC, Richland, Washington. 5 6 RPP-CALC-29700, 2014, Flammability Analysis and Time to Reach Lower Flammability Limit 7
Calculations for the 242-A Evaporator, Rev. 3, Washington River Protection Solutions 8 LLC, Richland, Washington. 9
Natural Phenomena Hazards, Rev. 0, Washington River Protection Solutions LLC, 43 Richland, Washington. 44
45
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RPP-RPT-53035, 2015, 242-A Evaporator C-A-1 Seismic Dump System – Functions and 1 Requirements Evaluation Document, Rev. 4, Washington River Protection Solutions 2 LLC, Richland, Washington. 3
4 RPP-RPT-54583, 2017, Design Analysis Report for the 242-A Evaporator C-A-1 Vessel 5
Flammable Gas Control System, Rev. 7, Washington River Protection Solutions LLC, 6 Richland, Washington. 7
8 RPP-RPT-54584, 2015, Design Analysis Report for the 242-A Evaporator C-A-1 Vessel Waste 9
High Level Control System, Rev. 5, Washington River Protection Solutions LLC, 10 Richland, Washington. 11
12 RPP-TE-53945, 2017, Technical Basis for 242-A Safety Instrumented Systems Sensing 13
Parameters and Timers, Rev. 2, Washington River Protection Solutions, Richland, 14 Washington. 15
16 RPP-TE-55027, 2013, 242-A Safety Significant Process Piping Equivalency B31.1-1973/2004 to 17
B31.3-2012, Rev. 0, Washington River Protection Solutions LLC, Richland, Washington. 18 19 RPP-TE-56679, 2014, Seismic 2 over 1 Evaluation for HS-CA1-1 – 242-A Evaporator 20
Emergency Stop Button, Rev. 0, Washington River Protection Solutions LLC, Richland, 21 Washington. 22
23 RPP-TE-58237, 2015, Technical Basis and Parameters for HV-CA1-5, Seismic Steam Shut-Off 24
Valve, Steam Shut-off Qualification, Rev. 0, Washington River Protection Solutions LLC, 25 Richland, Washington. 26
27 Smith, K. W., 2014, “Direction to Washington River Protection Solutions LLC to Amend Safety 28
Basis for 242-A Evaporator,” (letter 14-NSD-0013 to L. D. Olson, Washington River 29 Protection Solutions LLC, April 23), U.S. Department of Energy, Office of River 30 Protection, Richland, Washington. 31
32 TFC-ENG-DESIGN-C-10, Engineering Calculations, as amended, Washington River Protection 33
Solutions LLC, Richland, Washington. 34 35 TFC-ENG-STD-06, Design Loads For Tank Farm Facilities, as amended, Washington River 36
Protection Solutions LLC, Richland, Washington. 37 38 TFC-ESHQ-FP-STD-05, Flammable Gas Monitoring, as amended, Washington River Protection 39
Solutions LLC, Richland, Washington. 40 41 TFC-OPS-OPER-C-04, Access and Key Control for Operation Facilities, as amended, 42
Washington River Protection Solutions LLC, Richland, Washington. 43 44 TFC-OPS-OPER-C-22, Control and Use of Administrative Locks, as amended, Washington 45
River Protection Solutions LLC, Richland, Washington. 46 47
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TFC-PLN-02, Quality Assurance Program Description, as amended, Washington River 1 Protection Solutions LLC, Richland, Washington. 2
3 TO-600-140, Operate 242-A Overhead Crane, as amended, Washington River Protection 4
Solutions LLC, Richland, Washington. 5 6 TO-600-220, 242-A Evaporator Adjust PB-1 Seal Water Needle Valve, as amended, Washington 7
River Protection Solutions LLC, Richland, Washington. 8 9 TO-600-300, Perform Closeout Inspection in Evaporator Room and Pump Room, as amended, 10
Washington River Protection Solutions LLC, Richland, Washington. 11
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1
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F4 1 Figure 4.4.1-1. C-A-1 Vessel Flammable Gas Control System. 2
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Figure 4.4.2-1. C-A-1 Vessel Waste High Level Control System. 1
Figure 4.4.5-3. Location of Backflow Prevention Devices PSV-RW-3 and BPF-RW-11. 1
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1
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T4 1 Table 4.4.1-1. C-A-1 Vessel Flammable Gas Control System –
Failure Mode Evaluation.1
Condition
Con
ditio
n ad
dres
sed
by S
SC d
esig
n
Rea
dily
det
ecte
d fa
ilure
Defense-in-Depth Features2
Fire
pro
tect
ion
requ
irem
ents
Hoi
stin
g &
rigg
ing
prog
ram
3
Seismic loadings -- X4 -- -- Snow, ash, and wind loads5 X -- -- -- Dead loads, operating loads X -- -- -- 242-A Building temperatures X X -- -- Lightning X -- -- -- Exposure to water and humidity X -- -- -- Exposure to dust and ash X -- -- -- Process pressures X -- -- -- Process temperatures X -- -- -- Process chemistry/corrosion/erosion X -- -- -- Radiation fields X -- -- -- Sensing line plugging X -- -- -- Loss of power X -- -- -- General aging X -- -- -- Fires -- X X -- Load handling accidents -- X -- X
Interfacing Systems
C-A-1 vessel/recirculation line X -- -- -- Electrical power X -- -- -- Instrument air system X -- -- -- 10 lb/ft3 steam X -- -- -- Notes:
1 Failure modes that can fail the safety function based on failure mode and effects evaluation (see RPP-RPT-54583).
2 Defense-in-depth features are described in Section 3.3.2.3.2, “Defense-in-Depth.” 3 This safety management program applies to the 242-A Evaporator, and through normal
implementation of the program, provides defense-in-depth. 4 AC Key Element Emergency Preparedness requires actuating the C-A-1 vessel seismic dump system
following seismic events that could fail the C-A-1 vessel flammable gas control system. 5 Protected by safety-significant 242-A Building.
RPP-RPT-54583, 2017, Design Analysis Report for the 242-A Evaporator C-A-1 Vessel Flammable Gas
Control System, Rev. 7, Washington River Protection Solutions LLC, Richland, Washington.
AC = Administrative Control. SSC = structures, systems, and components.
2
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Table 4.4.2-1. C-A-1 Vessel Waste High Level Control System – Failure Mode Evaluation.1
Condition
Con
ditio
n ad
dres
sed
by S
SC d
esig
n
Rea
dily
det
ecte
d fa
ilure
Defense-in-Depth Features2
Fire
pro
tect
ion
requ
irem
ents
3
Hoi
stin
g &
rigg
ing
prog
ram
3
Seismic loadings N/A4 -- -- -- Snow, ash, and wind loads5 X -- -- -- Dead loads, operating loads X -- -- -- 242-A Building temperatures X X -- -- Lightning X -- -- -- Exposure to water and humidity X -- -- -- Exposure to dust and ash X -- -- -- Process pressure X -- -- -- Process temperatures X -- -- -- Process chemistry/corrosion/erosion X -- -- -- Radiation fields X -- -- -- Sediment accumulation/ plugging/fouling X -- -- -- General aging X -- -- -- Fires -- X X -- Load handling accidents -- X -- X
Interfacing Systems
C-A-1 vessel/recirculation line X -- -- -- Electrical power X -- -- -- Instrument air system X -- -- -- Notes:
1 Failure modes that can fail the safety function based on failure mode and effects evaluation (see RPP-RPT-54584).
2 Defense-in-depth features are described in Section 3.3.2.3.2, “Defense-in-Depth.” 3 These safety management programs apply to the 242-A Evaporator, and through normal
implementation of the programs, provide defense-in-depth. 4 A seismic event is not a credible initiator for the overflow of waste from the C-A-1 vessel to the
process condensate system. 5 Protected by safety-significant 242-A Building.
RPP-RPT-54584, 2015, Design Analysis Report for the 242-A Evaporator C-A-1 Vessel Waste High Level
Control System, Rev. 5, Washington River Protection Solutions LLC, Richland, Washington. N/A = not applicable. SSC = structures, systems, and components.
Seismic loadings4 X -- -- -- Snow, ash, and wind loads5 X -- -- -- Dead loads, operating loads X -- -- -- 242-A Building temperatures X -- -- -- Lightning X -- -- -- Exposure to water and humidity X -- -- -- Exposure to dust and ash X -- -- -- Process pressure X -- -- -- Process temperatures X -- -- -- Process chemistry/corrosion/erosion X -- -- -- Radiation fields X -- -- -- Sediment accumulation/ plugging/fouling X -- -- -- General aging X -- -- -- Fires -- X X -- Load handling accidents -- X -- X
Interfacing Systems
Waste transfer system X -- -- -- Instrument air X -- -- -- Electrical power X -- -- -- 10 lb/ft2 steam X -- -- -- Notes:
1 Failure modes that can fail the safety function based on failure mode and effects evaluation (see RPP-RPT-53035).
2 Defense-in-depth features are described in Section 3.3.2.3.2, “Defense-in-Depth.” 3 These safety management programs apply to the 242-A Evaporator, and through normal
implementation of the programs, provide defense-in-depth. 4 The safety-significant 242-A Building (Area 1, Area 2, and other internal structures) protects the
C-A-1 vessel seismic dump system from damage due to building and other internal structure (2 over 1) failure.
5 Protected by safety-significant 242-A Building.
RPP-RPT-53035, 2015, 242-A Evaporator C-A-1 Vessel Seismic Dump System – Functions and Requirements Evaluation Document, Rev. 4, Washington River Protection Solutions LLC, Richland, Washington.
Seismic loadings -- X4 -- -- Snow, ash, and wind loads5 X -- -- -- Dead loads, operating loads X -- -- -- 242-A Building temperatures X X -- -- Lightning X -- -- -- Process pressure6 X -- -- -- Process temperatures X -- -- -- Process chemistry/corrosion/erosion X -- -- X Radiation fields X -- -- -- General aging X -- -- -- Fires -- X X -- Load handling accidents N/A -- -- --
Interfacing Systems
Process steam system X -- -- -- Process air system X -- -- -- Notes:
1 Failure modes that can fail the safety function based on failure mode and effects evaluation (see RPP-RPT-52352).
2 Defense-in-depth features are described in Section 3.3.2.3.2, “Defense-in-Depth.” 3 This safety management program applies to the 242-A Evaporator, and through normal
implementation of the program, provides defense-in-depth. 4 AC Key Element Emergency Preparedness requires evacuating personnel from the condenser
room following seismic events that could fail the E-A-1 reboiler. 5 Protected by safety-significant 242-A Building. 6 Includes flow transients (water/steam hammer).
Seismic loadings -- X4 -- -- Snow, ash, and wind loads5 X -- -- -- Dead loads, operating loads X -- -- -- 242-A Building temperatures X -- -- -- Lightning X -- -- -- Exposure to water and humidity X -- -- -- Exposure to dust and ash X -- -- -- Process pressure6 X -- -- -- Process temperatures X -- -- -- Process chemistry/corrosion/erosion X -- -- -- Radiation fields7 X -- -- -- Sediment accumulation/ plugging/fouling X -- -- -- Check valve chatter X -- -- -- General aging X -- -- -- Fires -- X X -- Load handling accidents -- X -- X
Interfacing Systems
None -- -- -- -- Notes:
1 Failure modes that can fail the safety function based on failure mode and effects evaluation (see RPP-RPT-51829).
2 Defense-in-depth features are described in Section 3.3.2.3.2, “Defense-in-Depth.” 3 These safety management programs apply to the 242-A Evaporator, and through normal
implementation of the programs, provide defense-in-depth. 4 AC Key Element Emergency Preparedness requires evacuating untrained personnel from areas that
are not radiologically controlled following seismic events that could fail the backflow prevention devices. 5 Protected by safety-significant 242-A Building. 6 Includes flow transients (water hammer). 7 PSV-RW-3 is located in the 5th floor condenser room. High radiation fields are not present at this
location.
RPP-RPT-51829, 2016, 242-A Evaporator BFP-RW-11 and PSV-RW-3 Backflow Prevention Devices – Functions and Requirements Evaluation Document, Rev. 2, Washington River Protection Solutions LLC, Richland, Washington.
AC = Administrative Control. SSC = structures, systems, and components.
Seismic loadings -- X4 -- -- -- Snow, ash, and wind loads5 X -- -- -- -- Dead loads, operating loads X -- -- -- -- 242-A Building temperatures X X -- -- -- Lightning X -- -- -- -- Exposure to water and humidity X -- -- -- -- Exposure to dust and ash X -- -- -- -- Process pressure6 X -- -- -- -- Process temperatures X -- -- -- -- Process chemistry/corrosion/erosion X -- -- -- -- Radiation fields X -- -- -- -- Sediment accumulation/ plugging/fouling X -- -- -- -- Pressure relief valve chatter X -- -- -- -- General aging X -- -- -- -- Flammable gas deflagrations within process equipment -- -- X -- X
Fires -- X -- X -- Load handling accidents N/A -- -- -- --
Interfacing Systems
Raw water system X -- -- -- -- Notes:
1 Failure modes that can fail the safety function based on failure mode and effects evaluation (see RPP-RPT-42119). 2 Defense-in-depth features are described in Section 3.3.2.3.2, “Defense-in-Depth.” 3 This safety management program applies to the 242-A Evaporator, and through normal implementation of the
program, provides defense-in-depth. 4 AC Key Element Emergency Preparedness requires shutting down slurry pump P-B-2 following a seismic event
that could fail pressure relief valve PSV-PB2-1. 5 Protected by safety-significant 242-A Building. 6 Includes flow transients (water hammer).
LIST OF TERMS 9 10 11 AC Administrative Control 12 AMU aqueous makeup (room) 13 BBI Best-Basis Inventory 14 CFR Code of Federal Regulations 15 CPS criticality prevention specification 16 CSER criticality safety evaluation report 17 DF Design Feature 18 DOE U.S. Department of Energy 19 DSA documented safety analysis 20 DST double-shell tank 21 HVAC heating, ventilation, and cooling 22 ISC Ignition Source Control 23 JCI Johnson Controls, Inc. 24 LCO Limiting Condition for Operation 25 LFL lower flammability limit 26 MCS monitoring and control system 27 NFPA National Fire Protection Association 28 NQA nuclear quality assurance 29 ORP Office of River Protection 30 PAC Protective Action Criteria 31 SAC Specific Administrative Control 32 SIL Safety Integrity Level 33 SIS Safety Instrumented System 34 SMP safety management program 35 SpG specific gravity 36 SR Surveillance Requirement 37 SSC structures, systems, and components 38 Sv sievert 39 SWIM stop work, warn others, isolate the area, and minimize exposure 40 TMACS Tank Monitor and Control System 41 TOC Tank Operations Contractor 42 TSR technical safety requirement 43 ULD unit-liter dose 44 USOF unit sum-of-fractions 45 USQ unreviewed safety question 46
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5.0 DERIVATION OF TECHNICAL SAFETY REQUIREMENTS 1 2 3 5.1 INTRODUCTION 4 5 This chapter provides the information necessary for preparing the 242-A Evaporator Technical 6 Safety Requirements (TSR) (HNF-15279) required by Title 10, Code of Federal Regulations 7 (CFR), Part 830 (10 CFR 830), “Nuclear Safety Management,” Subpart B, “Safety Basis 8 Requirements,” 10 CFR 830.205, “Technical Safety Requirements.” HNF-15279 defines 9 acceptable conditions, safe boundaries, and management or administrative controls required to 10 ensure safe operation of the 242-A Evaporator. 11 12 This chapter provides summaries and references to pertinent sections of this document that 13 describe the design (i.e., structures, systems, and components [SSC]) and administrative features 14 identified for the potential hazardous conditions and postulated accidents. The Limiting 15 Conditions for Operation (LCO), Surveillance Requirements (SR), Specific Administrative 16 Controls (SAC), Key Elements of Administrative Controls (AC), AC programs (including Safety 17 Management Programs [SMP]), and Design Features form the basis of the TSR document and 18 provide the logical link between the TSR controls and the documented safety analysis (DSA). 19 20 Products of this chapter include the following: 21 22
• Derivation of operational modes. 23 24 • Derivation of minimum staffing levels. 25 26 • Derivation of LCOs/SRs. 27 28 • Derivation of SACs. 29 30 • Derivation of Key Elements of ACs. 31 32 • Summary of AC programs. 33 34 • Identification of Design Features. 35 36 • Identification of TSR interfaces with tank farms and other Hanford Site facilities and 37
operations. 38 39 • A table that links the TSR controls with applicable analyzed accidents. 40
41 42
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5.2 REQUIREMENTS 1 2 Design codes, standards, regulations, and U.S. Department of Energy (DOE) Orders required for 3 establishing the facility safety basis specific to this chapter include the following: 4 5
• 10 CFR 830 6 7 • DOE G 421.1-2, Implementation Guide for Use in Developing Documented Safety 8
Analyses to Meet Subpart B of 10 CFR 830 9 10 • DOE G 423.1-1, Implementation Guide for Use in Developing Technical Safety 11
Requirements 12 13 • DOE-STD-1186-2004, Specific Administrative Controls 14 15 • DOE-STD-3009-94, Preparation Guide for U.S. Department of Energy Nonreactor 16
Nuclear Facility Documented Safety Analyses 17 18 19 5.3 TECHNICAL SAFETY REQUIREMENTS COVERAGE 20 21 22 5.3.1 Summary 23 24 The suite of TSR controls for potential hazardous conditions and postulated accidents is 25 summarized in Table 5.3.1-1. Table 5.3.1-1 lists the TSR controls selected based on the hazard 26 and accident analyses in Chapter 3.0. Table 5.3.1-1 provides a cross-reference of the TSR 27 controls to the respective Chapter 3.0 sections. Section 5.5 provides the derivation bases for 28 each TSR control. 29 30 The required TSR controls are considered necessary and sufficient for public safety, significant 31 defense-in-depth, and significant facility worker safety. The primary Tank Operations 32 Contractor (TOC) SMPs that provide additional defense-in-depth are described in the 33 programmatic chapters of this DSA. Included are programs prescribed in 242-A Evaporator 34 regulatory and contractual systems that implement applicable requirements (e.g., radiation 35 protection, quality assurance). (See Section 5.5.3.7.) 36 37 38 5.4 DERIVATION OF FACILITY MODES 39 40 41 5.4.1 Operational Modes 42 43 Three Operational Modes (Shutdown, Limited Waste, and Operation) are defined for the 242-A 44 Evaporator as described below. 45 46
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SHUTDOWN MODE 1 2 The 242-A Evaporator is in the Shutdown Mode when the C-A-1 vessel is “empty of waste.” 3 “Empty of waste” is the condition when dump valves HV-CA1-7 and HV-CA1-9 have been 4 opened and as much waste as possible has been allowed to drain. Residual waste may remain on 5 some surfaces. After draining, the dump valves may be closed. The C-A-1 vessel is allowed to 6 contain water, antifoaming agents, process condensate, inhibited water (e.g., water treated with 7 hydroxide and/or nitrite used for corrosion control), etc., which may be added to support 8 maintenance, testing, or startup activities. 9 10 In the Shutdown Mode, there are two hazards, both involving facility workers in the evaporator 11 or pump room. One hazard is a flammable gas deflagration during manned work activities 12 involving waste feed transfer piping, waste slurry transfer piping, and C-A-1 vessel drain (dump) 13 piping (see Section 3.3.2.4.1). The Flammable Gas Controls for Waste Feed Transfer Piping, 14 Waste Slurry Transfer Piping, and C-A-1 Vessel Drain (Dump) Piping (SAC) protects facility 15 workers from this hazard (see Section 4.5.1). The other hazard involves direct radiation 16 exposure and/or waste leaks (i.e., chemical burn caused by wetting spray/jet/stream leaks) due to 17 the misroute of waste into the C-A-1 vessel from tank farms and waste transfer pump (pump 18 room sump steam jet pump) J-B-1 operation (see Section 3.3.2.4.3). The Evaporator and Pump 19 Room Access and Pump Room Cover Block Control (SAC) protects facility workers from this 20 hazard (see Section 4.5.2). 21 22 LIMITED WASTE MODE 23 24 The 242-A Evaporator is in Limited Waste Mode when the following conditions are met. 25 26
• Feed valve HV-CA1-1 is open. 27 • Feed pump 241-AW-P-102-1 breaker is open. 28 • Steam to the E-A-1 reboiler is isolated. 29 • Recirculation pump P-B-1 breaker is open. 30
31 Note: The Limited Waste Mode is entered only when dump valves HV-CA1-7 and/or 32
HV-CA1-9 cannot be opened to empty the C-A-1 vessel. The Limited Waste Mode is an 33 off-normal condition that results in approximately 2,700 gallons of residual waste 34 remaining in the C-A-1 vessel. 35
36 In the Limited Waste Mode, there are two hazards. The first hazard is to a facility worker in the 37 evaporator or pump room from direct radiation exposure and/or waste leaks (i.e., chemical burn 38 caused by wetting spray/jet/stream leaks) due waste in the C-A-1 vessel, the misroute of waste 39 into the C-A-1 vessel from tank farms, and waste transfer pump (pump room sump steam jet 40 pump) J-B-1 operation (see Section 3.3.2.4.3). The Evaporator and Pump Room Access and 41 Pump Room Cover Block Control (SAC) protects facility workers from this hazard (see 42 Section 4.5.2). The second hazard is to untrained personnel in areas that are not radiologically 43 controlled from the misroute of waste into the raw water system in uncontrolled areas (chemical 44 burn hazard) (see Section 3.3.2.4.3). Backflow prevention device BFP-RW-11, or its removal 45 from the raw water line (i.e., an air gap), protects untrained personnel from this hazard (see 46 Section 4.4.5). Emergency Preparedness (AC Key Element) also protects untrained personnel 47
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from this hazard following a seismic event that could cause failure of backflow prevention 1 device BFP-RW-11 (see Section 5.5.3.6). 2 3 OPERATION MODE 4 5 The 242-A Evaporator is in the Operation Mode when there is waste in the C-A-1 vessel, but the 6 242-A Evaporator is not in Limited Waste Mode. 7 8 In the Operation Mode multiple hazards are present and the following controls are applicable. 9 10
• C-A-1 Vessel Flammable Gas Control System (LCO) 11 • C-A-1 Vessel Waste High Level Control System (LCO) 12 • C-A-1 Vessel Seismic Dump System (LCO) 13 • Evaporator and Pump Room Access and Pump Room Cover Block Control (SAC) 14 • Evaporator and Pump Room Transient Combustible Material Controls (SAC) 15 • C-A-1 Vessel Time to Lower Flammability Limit (AC Key Element) 16 • Ignition Controls (AC Key Element) 17 • Waste Characteristics Controls (AC Key Element) 18 • Nuclear Criticality Safety (AC Key Element) 19 • Emergency Preparedness (AC Key Element) 20 • Emergency Response Actions Following Facility Fires (AC) 21 • E-A-1 Reboiler (Design Feature) 22 • Backflow Prevention Devices (PSV-RW-3 and BFP-RW-11) (Design Feature) 23 • Pressure Relief Valve (PSV-PB2-1) (Design Feature) 24 • 242-A Building (Design Feature) 25
26 27 5.4.2 Minimum Staffing Levels 28 29 Per DOE G 423.1-1, the required staffing of operating shifts for nonreactor nuclear facilities and 30 the members of the shift staff required to be present in the control room or control area for 31 different operating conditions should be specified on the basis of relevant safety analyses. 32 33 The minimum operations shift complement (interchangeably referred to as minimum staff) is 34 dependent on the Operational Mode. 35 36
• When the 242-A Evaporator is in the Shutdown Mode, the minimum staff is one shift 37 manager and one operator (either control room [A-1] or backside [A-2]). Both the shift 38 manager and the operator are normally shared with tank farms and neither is required to 39 be continuously at the 242-A Evaporator. 40
41 • When the 242-A Evaporator is in the Limited Waste Mode, the minimum staff is one 42
shift manager and one operator (either control room or backside). The shift manager is 43 normally shared with tank farms and is not required to be continuously at the 242-A 44 Evaporator. The operator is required to be continuously at the 242-A Evaporator. 45
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1 • When the 242-A Evaporator is in the Operation Mode, the minimum staff is one shift 2
manager and two operators (i.e., a control room operator and a backside operator). The 3 shift manager is not required to be continuously at the 242-A Evaporator, but is not 4 shared with tank farms. The control room operator and the backside operator are 5 required to be continuously at the 242-A Evaporator. 6
7 As described below, this minimum staff is considered adequate to perform the minimum safety 8 functions required by the TSRs during normal operations, and during abnormal and emergency 9 conditions. 10 11 In the Shutdown Mode, when there is no waste in the C-A-1 vessel, there are two hazards, but 12 neither requires operator action. The SAC Flammable Gas Controls for Waste Feed Transfer 13 Piping, Waste Slurry Transfer Piping, and C-A-1 Vessel Drain (Dump) Piping protects facility 14 workers from a flammable gas deflagration during manned work activities involving waste feed 15 transfer piping, waste slurry transfer piping, and C-A-1 vessel drain (dump) piping; and the SAC 16 Evaporator and Pump Room Access and Pump Room Cover Block Control protects facility 17 workers from direct radiation exposure and/or waste leaks (i.e., chemical burn caused by wetting 18 spray/jet/stream leaks) due to the misroute of waste into the C-A-1 vessel from tank farms and 19 waste transfer pump (pump room sump steam jet pump) J-B-1 operation. 20 21 In the Limited Waste Mode, when there is approximately 2,700 gallons of waste in the C-A-1 vessel, 22 there are two hazards. The SAC Evaporator and Pump Room Access and Pump Room Cover Block 23 Control protects facility workers from direct radiation exposure and/or waste leaks (i.e., chemical 24 burn caused by wetting spray/jet/stream leaks) due to waste in the C-A-1 vessel, the misroute of 25 waste into the C-A-1 vessel from tank farms, and waste transfer pump (pump room sump steam 26 jet pump) J-B-1 operation, and does not require operator actions. The safety-significant backflow 27 prevention device BFP-RW-11, or its removal from the raw water line (i.e., an air gap), protects 28 untrained personnel in areas that are not radiologically controlled from the misroute of waste into 29 the raw water system in uncontrolled areas (chemical burn hazard). The only operator action 30 required is evacuating personnel from areas that are not radiologically controlled following 31 seismic events that could cause failure of backflow prevention device BFP-RW-11 (see 32 Section 5.5.3.6), and the minimum staff is judged to be adequate to perform this function. 33 34 In the Operation Mode, the minimum staff is based on compliance with TSRs requiring 35 completion times of either immediately or 8 hr or less. Additional staff could be provided within 36 8 hours, if needed (considering the most adverse weather and travel conditions), to ensure that all 37 TSR requirements are met. The minimum staff does not include individuals necessary to fulfill 38 the 242-A Evaporator mission, goals, and objectives or individuals necessary to meet other 39 safety, environmental, and safety basis requirements and commitments. 40 41 During normal operations in the Operation Mode, there are no TSR requirements that have 42 completion times of either immediately or 8 hr or less. Less frequent TSR requirements, such as 43 LCO surveillance requirements and in-service inspections/tests for Design Features, are planned 44 and scheduled to ensure TSR compliance. These activities do not require performance by 45 minimum staff. Although minimum staff monitors facility conditions through performance of 46 routine operator rounds, these activities are not required by the TSRs and thus are performed as a 47
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matter of convenience and not as specific minimum staff functions. Thus the minimum staff is 1 judged to be adequate during normal operations to perform the necessary job functions. 2 3 During abnormal and emergency conditions while in the Operation Mode, the TSR requirements 4 that have completion time of immediately or 8 hr or less are pressing an emergency stop button 5 (AC 5.10.2). In addition, AC 5.9.6, “Emergency Preparedness,” includes actions to reduce the 6 risk of flammable gas accidents and waste transfer leaks and misroutes following a seismic event 7 and, although there are no stated completion times, these actions must be initiated promptly. 8 Fires at the 242-A Evaporator requiring the actions in AC 5.10.2 are not expected. In addition, 9 seismic events and post-seismic fires that could initiate the emergency response actions in 10 AC 5.9.6 are unlikely. Thus, the minimum staff is judged to be adequate during abnormal and 11 emergency conditions to perform necessary job functions. 12 13 AC 5.5.1.2 allows the minimum complement of personnel to be one person less than the required 14 number for a period of time not to exceed 4 hours. Allowing this temporary reduction in the 15 minimum staff accommodates unexpected absences, but requires that immediate action be taken 16 to restore the shift complement to within the minimum requirements stated above. Unexpected 17 absences are of most concern when the 242-A Evaporator is in the Operation Mode. However, 18 even in the Operation Mode with a temporary reduction in the minimum staff, there is qualified 19 personnel (i.e., the other two required minimum shift personnel) to perform, if required, an 20 emergency shutdown of the 242-A Evaporator (i.e., actuate the C-A-1 vessel seismic dump 21 system). Unexpected absence of minimum staff personnel (because of a personal emergency 22 which requires the personnel to leave the Hanford Site, or because of a health-related emergency 23 [including physical incapacitation] that renders the personnel incapable of performing assigned 24 duties) is expected to be a rare event. In the Limited Waste Mode, where the only operator 25 action required is evacuating personnel from areas that are not radiologically controlled 26 following seismic events that could cause failure of backflow prevention device BFP-RW-11, the 27 risk of a temporary reduction in the minimum staff at the same time as a seismic event is not 28 significant. 29 30 Qualification training for the minimum staff (managers, engineers, and operators) is addressed in 31 Chapter 12.0. The qualification program for the minimum staff meets federal and state 32 requirements, as implemented in TOC procedures. Training plans for the minimum staff specify 33 initial qualification requirements that include education, experience, medical considerations, or 34 an equivalency thereof. Requalification and continuing training is provided, as applicable. The 35 program for TSR, emergency, and alarm response administrative procedures is also addressed in 36 Chapter 12.0. Emergency response is addressed in Chapter 15.0. 37 38 39 5.5 TECHNICAL SAFETY REQUIREMENT DERIVATION 40 41 This section identifies the selected TSR controls and serves as an interface between the DSA and 42 TSR document. Detailed bases for the Design Features and SACs are provided in the referenced 43 Chapter 4.0 sections. 44 45 Table 5.3.1-1 provides cross references of the TSR controls to applicable analyzed accidents and 46 other DSA sections. 47
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1 2 5.5.1 Safety Limits/Limiting Control Settings 3 4 There are no safety limits for the 242-A Evaporator based on the conclusions found in 5 Chapter 3.0. 6 7 There are also no limiting control settings for the 242-A Evaporator because there are no safety 8 limits. 9 10 11 5.5.2 Limiting Conditions for Operation 12 13 LCOs are the lowest functional capability or performance level of safety SSCs (and their support 14 systems) required for normal, safe operation of the facility. Consistent with DOE-STD-1186-2004, 15 SACs that are identified to prevent or mitigate an accident scenario that have a safety function that 16 would be safety class or safety significant if the function were provided by an SSC may be 17 developed as LCOs. For the 242-A Evaporator, no SACs are developed as LCOs. 18 19 The derivation basis for the LCOs identified for the 242-A Evaporator is provided in the 20 following sections. Detailed basis for the LCOs are provided in the TSR document. 21 22 5.5.2.1 Limiting Condition for Operation 3.1 – C-A-1 Vessel Flammable Gas 23 Control System. 24 25 5.5.2.1.1 LCO and LCO Actions. Section 3.3.2.4.1, “Flammable Gas Accidents,” identifies 26 the C-A-1 vessel flammable gas control system as a safety-significant engineered feature to 27 prevent a flammable gas accident in the C-A-1 vessel. The C-A-1 vessel flammable gas control 28 system is described in Section 4.4.1. Since waste in the C-A-1 vessel is capable of generating 29 flammable gas and the C-A-1 vessel is postulated to reach 100% of the lower flammability limit 30 (LFL) if there is sufficient waste in the vessel, LCO 3.1 is applicable when in the Operation 31 Mode (see Section 5.4.1 for a definition of the Operational Modes). 32 33 The C-A-1 vessel flammable gas control system is a Safety Integrity Level (SIL)-2 safety 34 instrumented system (SIS). The C-A-1 vessel flammable gas control system monitors C-A-1 35 vessel vacuum, purge air flow, and waste temperature; and performs the following on high 36 C-A-1 vessel pressure (loss of vacuum) (> 200 Torr) and low C-A-1 vessel purge air flow 37 (< 3.0 standard ft3/min), or high waste temperature (> 160oF). (Note: To address potential 38 failure modes of the purge air flow switches, high purge air flow [> 14.0 standard ft3/min] in 39 conjunction with high C-A-1 vessel pressure also performs the following.) 40 41
• Feed pump 241-AW-P-102-1 is stopped. 42 • Feed valve HV-CA1-1 is opened to drain the C-A-1 vessel. 43 • Steam isolation valve HV-EA1-5 is closed. 44 • Recirculation pump P-B-1 is stopped. 45 • After a time delay, dump valves HV-CA1-7 and HV-CA1-9 are opened to empty the 46
C-A-1 vessel. 47
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1 The initial C-A-1 vessel flammable gas control system actions prevent a flammable gas accident 2 by draining the C-A-1 vessel via the feed line and limiting the temperature of the residual waste. 3 Because draining the C-A-1 vessel via the feed line leaves approximately 2,700 gallons of waste 4 in the C-A-1 vessel, limiting the temperature of the residual waste in the C-A-1 vessel by stopping 5 steam flow to the E-A-1 boiler (i.e., closing steam isolation valve HV-EA1-5) and stopping 6 recirculation pump P-B-1 is required. That is, based on the analysis in RPP-CALC-29700, 7 Flammability Analysis and Time to Reach Lower Flammability Limit Calculations for the 242-A 8 Evaporator, the 2,700 gallons of residual waste in the C-A-1 vessel is not a flammable gas hazard 9 (i.e., the flammable gas concentration in the C-A-1 vessel will not reach 100% of the LFL) 10 (see Section 4.4.1). 11 12 The additional action of opening dump valves HV-CA1-7 and HV-CA1-9 is a redundant method 13 of preventing a flammable gas accident by emptying the C-A-1 vessel. 14 15 If the C-A-1 vessel flammable gas control system is not operable, the 242-A Evaporator must be 16 placed in the Shutdown Mode or the Limited Waste Mode (see Section 5.4.1) within 24 hours. 17 Placing the 242-A Evaporator in the Shutdown Mode (i.e., the C-A-1 vessel is “empty of waste”) 18 eliminates the flammable gas hazard (i.e., there is no waste in the C-A-1 vessel). If dump valves 19 HV-CA1-7 and/or HV-CA1-9 cannot be opened to empty the C-A-1 vessel, placing the 242-A 20 Evaporator in the Limited Waste Mode also prevents the flammable gas hazard. In the Limited 21 Waste Mode, the feed pump 241-AW-P-102-1 breaker is open and feed valve HV-CA1-1 is open 22 (i.e., the C-A-1 vessel is drained, except for approximately 2,700 gallons); and steam isolation 23 valve HV-EA1-5 is closed and the recirculation pump P-B-1 breaker is open, which limits the 24 heat input and temperature of the residual waste left in the C-A-1 vessel. 25 26 The action completion time of 24 hours is less than or equal to the minimum time for the 27 flammable gas concentration to increase by 25% of the LFL in the C-A-1 vessel, which is 28 protected by AC 5.9.1, “C-A-1 Vessel Time to Lower Flammability Limit” (see Section 5.5.3.1). 29 Because the 24 hour action completion time is based on not exceeding the minimum time for the 30 flammable gas concentration to increase by 25% of the LFL, the flammable gas concentration 31 could theoretically exceed 25% of the LFL prior to completing the action if the starting C-A-1 32 vessel headspace flammable gas concentration is above 0% of the LFL. The risk of the C-A-1 33 vessel flammable gas control system being challenged during this action completion time and the 34 flammable gas concentration exceeding 25% of the LFL is acceptable because (1) loss of 35 vacuum AND low purge air flow, OR high waste temperature, are off-normal conditions (not 36 caused by C-A-1 vessel flammable gas control system failures); and (2) the general service 37 monitoring and control system (MCS) detects and prevents these off-normal conditions before 38 challenging the C-A-1 vessel flammable gas control system. In addition, the analysis of the 39 minimum time for the flammable gas concentration to increase by 25% of the LFL is 40 conservative and, with the margin of safety provided by the 25% of the LFL control point, the 41 flammable gas concentration in the C-A-1 vessel headspace could not challenge 100% of the 42 LFL. 43 44 5.5.2.1.2 Surveillance Requirements. To be operable, the C-A-1 vessel flammable gas control 45 system must be calibrated, calibration checked, and functionally tested as described in 46 Section 4.4.1. The surveillance frequency for the calibrations, calibration checks, and functional 47
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tests is established by the SIL calculation to ensure that C-A-1 vessel flammable gas control 1 system reliability meets SIL-2 requirements (see Section 4.4.1). 2 3 5.5.2.2 Limiting Condition for Operation 3.2 – C-A-1 Vessel Waste High 4 Level Control System. 5 6 5.5.2.2.1 LCO and LCO Actions. Section 3.3.2.4.1, “Flammable Gas Accidents,” and 7 Section 3.3.2.4.3, “Waste Leaks and Misroutes,” identify the C-A-1 waste high level control 8 system as a safety-significant engineered feature to prevent the overflow of waste from the 9 C-A-1 vessel into the process condensate system. The C-A-1 vessel waste high level control 10 system is described in Section 4.4.2. The overflow of waste from the C-A-1 vessel into the 11 process condensate system, which also includes boil-over of waste from the C-A-1 vessel caused 12 by a sudden increase in vacuum and carry-over of waste from the C-A-1 vessel caused by 13 foaming, is only possible if there is sufficient waste in the vessel. Therefore, LCO 3.2 is 14 applicable when in the Operation Mode (see Section 5.4.1 for a definition of the Operational 15 Modes). 16 17 The C-A-1 vessel waste high level control system is a Safety Integrity Level (SIL)-1 safety 18 instrumented system (SIS). The C-A-1 vessel waste high level control system monitors the 19 differential pressure between two air sensing lines ½”I-CA1-2-M31 and ½”I-CA1-3-M31 that 20 are located above and below the lower C-A-1 vessel de-entrainment pad, respectively. The 21 differential pressure increases when the waste level increases above the lower sensing line. The 22 differential pressure across the lower de-entrainment pad also increases when the waste in the 23 C-A-1 vessel is boiling or foaming. On sensing a high differential pressure (> 8 inch w.g. 24 differential), the C-A-1 vessel waste high level control system performs the following. (Note: 25 The C-A-1 vessel waste high level control system also performs the following on sensing high or 26 low air flow through the two air sensing lines ½”I-CA1-2-M31 and ½”I-CA1-3-M31 [see 27 Section 4.4.2].) 28 29
• Vacuum break valve HV-EC1-5 is opened. 30 • Feed pump 241-AW-P-102-1 is stopped. 31 • Feed valve HV-CA1-1 is opened to drain the C-A-1 vessel. 32 • After a time delay, dump valves HV-CA1-7 and HV-CA1-9 are opened to empty the 33
C-A-1 vessel. 34 35 Opening the vacuum break valve HV-EC1-5 prevents boil-over or carry-over from the C-A-1 36 vessel. Stopping the feed pump 241-AW-P-102-1, opening feed valve HV-CA1-1, and opening 37 dump valves HV-CA1-7 and HV-CA1-9, after a time delay, prevent the overflow of waste from 38 the C-A-1 vessel into the process condensate system. 39 40 If the C-A-1 vessel waste high level control system is not operable, the 242-A Evaporator must 41 be placed in the Shutdown Mode or the Limited Waste Mode (see Section 5.4.2) within 24 hours. 42 Placing the 242-A Evaporator in the Shutdown Mode (i.e., the C-A-1 vessel is “empty of 43 waste”), eliminates the hazard of overflow of C-A-1 waste into the process condensate system. 44 If dump valves HV-CA1-7 and/or HV-CA1-9 cannot be opened to empty the C-A-1 vessel, 45 placing the 242-A Evaporator in the Limited Waste Mode also prevents an overflow of waste 46 from the C-A-1 vessel into the process condensate system because the feed pump 47
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241-AW-P-102-1 breaker is open and feed valve HV-CA1-1 is open leaving only approximately 1 2,700 gallons in the C-A-1 vessel. 2 3 The action completion time of 24 hours is consistent with LCO 3.1 for the C-A-1 vessel 4 flammable gas control system (see Section 5.5.2.1), with which the C-A-1 vessel waste high 5 level control system shares several components (e.g., feed valve HV-CA1-1, dump valves 6 HV-CA1-7 and HV-CA1-9, feed pump 241-AW-P-102-1 contactor M-PAW-102A). The risk of 7 the C-A-1 vessel waste high level control system being challenged during this action completion 8 time is acceptable because (1) boil-over, carry-over, or overflow of waste from the C-A-1 vessel 9 into the process condensate system are off-normal conditions (not caused by C-A-1 vessel waste 10 high level control system failures); and (2) the general service MCS detects and prevents these 11 off-normal conditions before challenging the C-A-1 vessel waste high level control system. 12 13 5.5.2.2.2 Surveillance Requirements. To be operable, the C-A-1 vessel waste high level 14 control system must be calibrated, calibration checked, and functionally tested as described in 15 Section 4.4.2. The surveillance frequency for the calibrations, calibration checks, and functional 16 tests is established by the SIL calculation to ensure that the C-A-1 vessel waste high level control 17 system reliability meets SIL-1 requirements (see Section 4.4.2). 18 19 5.5.2.3 Limiting Condition for Operation 3.3 – C-A-1 Vessel Seismic Dump System. 20 21 5.5.2.3.1 LCO and LCO Actions. Section 3.3.2.4.5, “Natural Events,” identifies the C-A-1 22 waste seismic dump system as a safety-significant engineered feature to prevent a flammable gas 23 accident in the C-A-1 vessel. The C-A-1 vessel seismic dump system is described in 24 Section 4.4.3. Since flammable gas in the C-A-1 vessel is only postulated to reach 100% of the 25 lower flammability limit (LFL) if there is sufficient waste in the vessel (> 2,700 gallons), 26 LCO 3.3 is only applicable when in the Operation Mode (see Section 5.4.1 for a definition of the 27 Operational Modes). 28 29 The C-A-1 vessel seismic dump system is seismically qualified to operate following a design 30 basis earthquake. The C-A-1 vessel seismic dump system is manually actuated by pushing an 31 emergency stop button (i.e., HS-CA1-1 located on the external, southeast wall of the 242-A 32 Building) following a seismic event (see Section 5.5.3.6, “Administrative Control 5.9.6 - 33 Emergency Preparedness”). Actuating the C-A-1 vessel seismic dump system performs the 34 following. 35 36
• Feed pump 241-AW-P-102-1 is stopped. 37 • Feed valve HV-CA1-1 is opened to drain the C-A-1 vessel. 38 • Steam isolation valve HV-EA1-5 is closed. 39 • Recirculation pump P-B-1 is stopped. 40
41 Note: The C-A-1 vessel seismic dump system also opens dump valves HV-CA1-7 and 42
HV-CA1-9 to empty the C-A-1 vessel, but these valves are not seismically qualified. 43 44 These C-A-1 vessel flammable gas control system actions prevent a flammable gas accident 45 following a seismic event by draining the C-A-1 vessel via the feed line and limiting the 46
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temperature of the residual waste. Because draining the C-A-1 vessel via the feed line leaves 1 approximately 2,700 gallons of waste in the C-A-1 vessel, limiting the temperature of the 2 residual waste in the C-A-1 vessel by stopping steam flow to the E-A-1 boiler (i.e., closing steam 3 isolation valve HV-EA1-5) and stopping recirculation pump P-B-1 is required. That is, based on 4 the analysis in RPP-CALC-29700, Flammability Analysis and Time to Reach Lower 5 Flammability Limit Calculations for the 242-A Evaporator, the 2,700 gallons of residual waste in 6 the C-A-1 vessel is not a flammable gas hazard (i.e., the flammable gas concentration in the 7 C-A-1 vessel will not reach 100% of the LFL) (see Section 4.4.1). 8 9 If the C-A-1 vessel seismic dump system is not operable, the 242-A Evaporator must be placed 10 in the Shutdown Mode or the Limited Waste Mode (see Section 5.4.1) within 24 hours. Placing 11 the 242-A Evaporator in the Shutdown Mode (i.e., the C-A-1 vessel is “empty of waste”), 12 eliminates the flammable gas hazard (i.e., there is no waste in the C-A-1 vessel). If dump valves 13 HV-CA1-7 and/or HV-CA1-9 cannot be opened to empty the C-A-1 vessel, placing the 242-A 14 Evaporator in the Limited Waste Mode also prevents the flammable gas hazard. In the Limited 15 Waste Mode, the feed pump 241-AW-P-102-1 breaker is open and feed valve HV-CA1-1 is open 16 (i.e., the C-A-1 vessel is drained, except for approximately 2,700 gallons); and steam isolation 17 valve HV-EA1-5 is closed and the recirculation pump P-B-1 breaker is open, which limits the 18 heat input and temperature of the residual waste left in the C-A-1 vessel. 19 20 The action completion time of 24 hours is consistent with LCO 3.1 for the C-A-1 vessel 21 flammable gas control system, with which the C-A-1 vessel seismic dump system shares several 22 components (e.g., feed valve HV-CA1-1, steam isolation valve HV-EA1-5, feed pump 23 241-AW-P-102-1 contactor M-PAW-102A, recirculation pump P-B-1 contactor M-PB-1A). The 24 risk of a seismic event that requires initiation of the C-A-1 vessel seismic dump system during 25 this action completion time is acceptable. 26 27 5.5.2.3.2 Surveillance Requirements. To be operable, the C-A-1 vessel seismic dump system 28 must be functionally tested as described in Section 4.4.3. The surveillance frequency for the 29 functional tests is established consistent with the surveillance frequency of the C-A-1 vessel 30 flammable gas control system because the C-A-1 vessel seismic dump system shares several 31 components (e.g., feed valve HV-CA1-1, steam isolation valve HV-EA1-5, feed pump 32 241-AW-P-102-1 contactor M-PAW-102A, recirculation pump P-B-1 contactor M-PB-1A) with 33 this system (see Section 4.4.3). 34 35 36 5.5.3 Administrative Controls 37 38 ACs are the provisions relating to organization and management, procedures, recordkeeping, 39 assessment, and reporting; the safety management programs; and the directed action SACs and 40 AC Key Elements necessary to ensure safe operation of a facility. Consistent with 41 DOE-STD-1186-2004, SACs that are identified to prevent or mitigate an accident scenario and 42 that have a safety function that would be safety class or safety significant if the function were 43
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provided by an SSC may be developed as directed action ACs. The following directed action 1 ACs are developed from SACs in Chapter 4.0. 2 3
• Administrative Control 5.8.1 – Flammable Gas Controls for Waste Feed Transfer Piping, 4 Waste Slurry Transfer Piping, and C-A-1 Vessel Drain (Dump) Piping (Section 4.5.1). 5
6 • Administrative Control 5.8.2 – Evaporator and Pump Room Access and Pump Room 7
Cover Block Control (Section 4.5.2). 8 9 Some ACs were selected to provide an important contribution to defense-in-depth or provide a 10 support function to LCOs and SACs. These ACs are identified as Key Elements of ACs and are 11 developed in Sections 5.5.3.1, 5.5.3.2, 5.5.3.4, and 5.5.3.6. An AC Key Element for Nuclear 12 Criticality Safety is developed in Section 5.5.3.5 consistent with DOE Office of River Protection 13 (ORP) direction in the tank farms safety basis. Section 5.5.3.7 develops the Safety Management 14 Programs that provide defense-in-depth. Two ACs are required until completion of planned 15 design improvements and are developed in Sections 5.5.3.8 and 5.5.3.9. 16 17 TSR Sections 5.1 through 5.5 provide the ACs related to the administration of the TSRs. 18 19
• Section 5.1 – Purpose: This section provides an introduction to the AC section of the 20 TSR document. 21
22 • Section 5.2 – Contractor Responsibility: This section outlines the TOC organizational 23
responsibilities that serve to focus the attention of management, operations, and oversight 24 personnel on the highest operational safety provided by the TSRs. 25
26 • Section 5.3 – Compliance: This section establishes the TOC organizational positions 27
responsible for ensuring that requirements of the TSR are met. This section also 28 identifies how compliance with the TSRs shall be demonstrated. 29
30 • Section 5.4 – Technical Safety Requirements Violations: This section defines the TSR 31
violation criteria and the actions to take in response to a TSR violation. Criteria are 32 provided for TSR violations related to LCOs, SACs, AC Programs (including Key 33 Element of ACs), and Design Features. 34 35
• Section 5.5 – Organization: This section establishes the lines of authority, responsibility, 36 and communication at all management levels through intermediate levels, including all 37 safety and operating organizations. This section also establishes the minimum operations 38 shift compliment necessary to operate and support the 242-A Evaporator safely. 39
40
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5.5.3.1 Administrative Control 5.9.1 – C-A-1 Vessel Time to Lower Flammability Limit. 1 2 5.5.3.1.1 Safety Function. The safety functions of the AC Key Element C-A-1 Vessel Time to 3 Lower Flammability Limit are: 4 5
• To protect assumptions used to develop the action completion times in LCO 3.1, “C-A-1 6 Vessel Flammable Gas Control System” (see Section 5.5.2.1). 7
8 • To protect the response times for emergency actions in AC 5.10.2, “Emergency Response 9
Actions Following Facility Fires” (see Section 5.5.3.9). 10 11 5.5.3.1.2 Key Element Description. Prior to each 242-A-Evaporator campaign, a waste 12 compatibility assessment is prepared in accordance with TFC-ENG-CHEM-P-13, Tank Waste 13 Compatibility Assessments, that includes the time to LFL analysis for the planned waste in the 14 C-A-1 vessel. The time to LFL analysis for the C-A-1 vessel is based on the C-A-1 vessel 15 physical characteristics, the waste characteristics and conditions, and the waste temperature. The 16 time to LFL analysis is performed in accordance with the methodology described in 17 RPP-CALC-29700, Flammability Analysis and Time to Reach Lower Flammability Limit 18 Calculations for the 242-A Evaporator. 19 20 The action completion times for LCO 3.1 (i.e., 24 hours) must be less or equal to the time for the 21 flammable gas concentration to increase by 25% of the LFL assuming a waste temperature of 22 160°F. The response times for emergency actions in AC 5.10.2 (i.e., 40 minutes to press an 23 emergency stop button must be less or equal to the time for the flammable gas concentration to 24 increase by 25% of the LFL assuming a waste temperature of 230°F. (Note: Although the 25 response time in AC 5.10.2 for pressing an emergency stop button is 40 min, the limiting time 26 for the flammable gas concentration to increase by 25% of the LFL assuming a waste 27 temperature of 230oF is 1.9 hours to support the evaluation of the emergency response actions 28 following facility fires in Section 5.5.3.9). In addition, the time to LFL analysis must assume: 29 30
• No vacuum and zero ventilation. 31 • Waste at the maximum operational level (26,000 gallons). 32 • Waste specific gravity (SpG) of 1.6. 33 • Waste slurry NH3 concentration that is 30% of the feed waste NH3 concentration. 34 • Three drums of antifoam prior to concentration. 35
36 These requirements (i.e., the decision rule for the C-A-1 vessel time to LFL analysis) are 37 identified in HNF-SD-WM-OCD-015, Tank Farms Waste Transfer Compatibility Program, 38 Section 3.2.1, AC 5.9.1, C-A-1 Vessel Time to Lower Flammability Limit.” The evaluation is 39 documented, and a second engineer checks the evaluation. 40 41 5.5.3.1.3 Functional Requirement. The AC Key Element C-A-1 Vessel Time to Lower 42 Flammability Limit requires verification that the minimum time for the flammable gas 43 concentration to increase by 25% of the LFL in the C-A-1 headspace for the planned waste in the 44 C-A-1 vessel is > 24 hours assuming a waste temperature of 160°F and > 1.9 hours assuming a 45 waste temperature of 230°F. 46
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1 5.5.3.1.4 Key Element Evaluation. The time to LFL analysis are performed in accordance 2 with the TOC waste compatibility program and procedures (i.e., HNF-SD-WM-OCD-015 and 3 TFC-ENG-CHEM-P-13). 4 5 The first time to LFL analysis requirement is that action completion times for LCO 3.1 6 (i.e., 24 hours) must be less than or equal to the time for the flammable gas concentration in the 7 C-A-1 vessel headspace to increase by 25% of the LFL assuming a waste temperature of 160°F. 8 A waste temperature of 160°F is a reasonably conservative temperature and well above the 9 normal operating conditions that are controlled by the MCS. The actions of LCO 3.1 place the 10 242-A Evaporator in a safe Operational Mode (i.e., Shutdown Mode or Limited Waste Mode) to 11 prevent a flammable gas accident in the C-A-1 vessel if the C-A-1 Vessel Flammable Gas 12 Control System is not operable (see Section 5.5.2.1). 13 14 The second time to LFL analysis requirement is that the response times for emergency actions in 15 AC 5.10.2 (i.e., 40 min to press an emergency stop button must be less than or equal to the time 16 for the flammable gas concentration in the C-A-1 vessel headspace to increase by 25% of the 17 LFL assuming a waste temperature of 230°F). A waste temperature of 230°F is the maximum 18 C-A-1 waste temperature based on the steam pressure and temperature in the E-A-1 reboiler 19 (RPP-CALC-29700). The emergency response actions in AC 5.10.2 place the 242-A Evaporator 20 in a safe and stable condition. 21 22 For the time to LFL analysis, no vacuum (C-A-1 vessel under ambient pressure) and zero 23 ventilation are bounding assumptions. Assuming waste is at the maximum operational level 24 (26,000 gallons) is a reasonably conservative assumption that is controlled by the MCS. A waste 25 specific gravity (SpG) of 1.6 is also reasonably conservative assumption and well above the 26 normal operating conditions that are controlled by the MCS. Assuming the waste slurry 27 ammonia (NH3) concentration is 30% of the waste feed NH3 concentration is conservative 28 relative to operating experience (see RPP-CALC-29700). Ammonia is assumed to be at 29 equilibrium at all times, and, therefore the time from 0% to 25% of the LFL is the shortest time 30 to increase by 25% of the LFL and is conservative. In addition, assuming three drums of 31 antifoam in the C-A-1 vessel prior to concentration is reasonably conservative (see 32 RPP-CALC-29700, Appendix D, “Technical Basis for the Amount of Antifoam in the C-A-1 33 Evaporator Vessel”). This collective set of assumptions for waste in the C-A-1 vessel is 34 bounding. 35 36 5.5.3.1.5 Controls (TSRs). The C-A-1 Vessel Time to Lower Flammability Limit is a Key 37 Element of an Administrative Control (i.e., programmatic AC) with the following requirement 38 that is applicable in the Operation Mode. 39 40
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The minimum time for the flammable gas concentration to increase by 25% of the LFL in the 1 headspace of the C-A-1 vessel for planned waste in the C-A-1 vessel calculated using the 2 methodology in RPP-CALC-29700 shall be: 3 4
1. > 24 hours assuming a waste temperature of 160°F. 5 6
AND 7 8
2. ≥ 1.9 hours assuming a waste temperature of 230°F. 9 10 The analysis of the minimum time for the flammable gas concentration to increase by 25% of the 11 LFL shall also assume: 12 13
• No vacuum and zero ventilation. 14 • Waste at the maximum operational level (26,000 gallons). 15 • Waste SpG of 1.6. 16 • Waste slurry NH3 concentration that is 30% of the feed waste NH3 concentration. 17 • Three drums of antifoam prior to concentration. 18
19 5.5.3.2 Administrative Control 5.9.2 – Ignition Controls. 20 21 5.5.3.2.1 Safety Function. The safety functions of the AC Key Element Ignition Controls are: 22 23
1. To establish ignition control requirements consistent with applicable codes and standards, 24 including National Fire Protection Association (NFPA) requirements, for control of 25 potential flammable gas ignition sources. 26
27 2. To evaluate installed equipment to ensure compliance with ignition control requirements 28
or provision of equivalent safety. 29 30
3. To evaluate manned work activities to determine the applicability of, and ensure 31 compliance with, ignition control requirements or provision of equivalent safety. 32
33 This AC Key Element supports implementation of the ignition control requirements contained in 34 the following flammable gas control. 35 36
SAC Flammable Gas Controls for Waste Feed Transfer Piping, Waste Slurry Transfer 37 Piping, and C-A-1 Vessel Drain (Dump) Piping (see Section 4.5.1). 38
39 This control is selected as an AC Key Element to provide a safety support function for the above 40 listed SAC (see Section 3.3.2.4.1). 41 42 5.5.3.2.2 Key Element Description. Ignition control requirements consistent with applicable 43 codes and standards, including NFPA requirements are included in the engineering standard 44 TFC-ENG-STD-13, Ignition Source Controls for Potentially Flammable Atmospheres and 45
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TFC-ENG-STD-45, Design and Installations for Potentially Flammable Atmospheres. The 1 ignition control requirements consist of two control sets. 2 3
• Ignition Source Control (ISC) Set 1, which is consistent with ignition controls for areas 4 classified as Class 1, Division 1, Group B as defined in NFPA 497, Recommended 5 Practice for the Classification of Flammable Liquids, Gases, or Vapors and of 6 Hazardous (Classified) Locations for Electrical Installations in Chemical Process Areas. 7
8 • ISC Set 2, which is consistent with ignition controls for areas classified as Class 1, 9
Division 2, Group B as defined in NFPA 497. 10 11 The engineering standard TFC-ENG-STD-45 addresses ignition controls applicable to design, 12 procurement, and installation of equipment; TFC-ENG-STD-13 addresses ignition controls for 13 manned work activities (work practices, equipment, and materials). TFC-ENG-STD-13 also 14 includes historical information on the activity work practices, equipment, and materials and 15 previously installed equipment that have been evaluated for compliance with ISC Set 1 or ISC 16 Set 2, as applicable, or provide equivalent safety to the ignition control requirements. 17 18 The physical locations and boundaries within which flammable gas hazards exist and ignition 19 controls are required have been determined in accordance with NFPA 70, National Electrical 20 Code and NFPA 497, and documented in RPP-RPT-58290, NFPA Flammable Vapor and Gas 21 Hazard Classification for the 242-A Evaporator. This document defines ignition control 22 applicability. 23 24 Design and evaluation of installed equipment to determine applicability of, and compliance with, 25 ignition control requirements is done in accordance with TFC-ENG-STD-45, and evaluation of 26 activity work practices, equipment, and materials to determine the applicability of, and compliance 27 with, ignition control requirements is done in accordance with TFC-ENG-FACSUP-P-17, 28 Flammable Gas Activities Ignition Source Control. 29 30 For manned work activities, the responsible engineer determines if the activity and associated 31 work practices, equipment, and materials have previously been evaluated and included in 32 TFC-ENG-STD-13. If the activity work practices, equipment, and materials have been 33 evaluated, the responsible engineer documents the specific entry from TFC-ENG-STD-13, or 34 other approved evaluation if not yet incorporated in TFC-ENG-STD-13, as required by 35 TFC-ENG-FACSUP-P-17; this documentation is reviewed by a second engineer. 36 37 If the activity work practices, equipment, and materials are not listed in TFC-ENG-STD-13, or 38 otherwise previously evaluated and pending incorporation in TFC-ENG-STD-13, the responsible 39 engineer prepares a technical evaluation or technical report documenting the basis for 40 compliance with applicable codes and standards, or the basis for a determination of equivalent 41 safety. This technical evaluation receives a review by a second engineer, and must be approved 42 by the appropriate subject matter expert(s) as delegated by the Chief Engineer. The results of the 43 evaluation are incorporated into TFC-ENG-STD-13. 44 45 For design, procurement, and installation of equipment, the responsible engineer is prompted via 46 the suite of procedures governing the design and procurement process to define the applicable 47
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requirements, including codes and standards for explosion prevention/ignition source control. 1 For equipment to be installed or used in any location classified as hazardous under NFPA 70 and 2 NFPA 497, as documented in RPP-RPT-58290, equipment design must comply with applicable 3 codes and standards. For designs or installations where any determination of equivalent safety is 4 necessary, the responsible engineer prepares a technical evaluation or technical report 5 documenting the basis for the requested design deviation, as outlined in TFC-ENG-STD-45. 6 This technical evaluation receives a review by a second engineer, and must be approved by the 7 appropriate subject matter expert(s) as delegated by the Chief Engineer. 8 9 5.5.3.2.3 Functional Requirement. The AC Key Element Ignition Controls requires that 10 ignition control requirements are: 11 12
1. Established consistent with applicable codes and standards, including NFPA 13 requirements, with the Chief Engineer, or delegate, approval required for equivalency 14 determinations. 15
16 2. Implemented to control potential ignition sources associated with installed equipment and 17
manned work activities when required by other flammable gas controls (see 18 Section 5.5.3.2.1). 19
20 5.5.3.2.4 Key Element Evaluation. The primary hazard to the facility worker from a 21 flammable gas deflagration/detonation is the potential for grievous injury or death due to 22 overpressure or physical impact from SSC failure (missiles). These hazards are the same as 23 other potential flammable gas events not related to waste. Using the ignition control 24 requirements (which are consistent with applicable codes and standards, including NFPA 25 requirements) as the basis for determining the required level of ignition controls provides an 26 adequate method for assuring worker safety from flammable gas deflagrations or detonations. 27 28 For manned work activities, activity work practices, equipment, and materials are evaluated to 29 determine the applicability and compliance with ignition control requirements, and to determine 30 an appropriate set of controls consistent with applicable codes and standards, including NFPA 31 requirements. The use of standard engineering documentation with independent review provides 32 adequate assurance that appropriate and consistent controls are provided for manned work 33 activities. 34 35 If the applicable ignition control requirements (as previously defined and documented in 36 TFC-ENG-STD-13) are not fully met, the method to provide equivalent safety to ignition control 37 requirements is determined and documented. The determination is documented in a technical 38 evaluation or technical report, which is subject to the engineering document review process. 39 Any determination of equivalent safety is approved by the Chief Engineer, or delegate. 40 41 For installed equipment, the engineering design, procurement, and installation processes require 42 identification of applicable codes and standards, including ignition controls. The emphasis on 43 compliance in design and procurement provides adequate assurance that compliance is addressed 44 prior to equipment installation. If the applicable ISC Set 1 or Set 2 ignition control requirements 45 cannot be fully met, the method to provide equivalent safety is determined and documented. The 46 determination is documented in a technical evaluation or report, prepared in accordance with 47
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TFC-ENG-STD-45, which is subject to the engineering document review process. Any 1 determination of equivalent safety is approved by the Chief Engineer, or delegate. 2 3 Specific equipment and material required to meet ignition control requirements are not classified 4 as safety significant. The equipment and material are potential event initiators and do not 5 provide a safety function. The equipment and material are potential ignition controls, which are 6 adequately controlled under this AC Key Element. 7 8 5.5.3.2.5 Controls (TSRs). Ignition Controls is a Key Element of an Administrative Control 9 (i.e., programmatic AC) with the following requirements. 10 11
1. Ignition control requirements shall be established consistent with applicable codes and 12 standards, including NFPA requirements. The Chief Engineer, or delegate, shall be the 13 approval authority for equivalency to the established ignition control requirements. 14
15 2. Ignition controls are required by the following TSR. 16
17 AC 5.8.1, “Flammable Gas Controls for Waste Feed Transfer Piping, Waste Slurry 18 Transfer Piping, and C-A-1 Vessel Drain (Dump) Piping.” 19 20 For installed equipment and manned work activities required to meet ignition controls 21 required by the above TSR, an evaluation shall be performed to: 22
23 a. Determine the applicable ignition control requirements. 24
25 b. Determine that the installed equipment or manned work activity complies with the 26
applicable ignition control requirements or provides equivalent safety to the 27 ignition control requirements. 28
29 5.5.3.3 Administrative Control 5.9.3 – Reserved for Future Use. 30 31 5.5.3.4 Administrative Control 5.9.4 – Waste Characteristics Controls. 32 33 5.5.3.4.1 Safety Function. The safety function of the AC Key Element Waste Characteristics 34 Controls is to protect assumptions on waste characteristics used to estimate accident 35 consequences by ensuring that unit-liter doses (ULD), unit sum-of-fractions (USOF), and 90Sr 36 and 137Cs concentrations are within the values used in the DSA safety analysis. 37 38 5.5.3.4.2 Key Element Description. Consequences of postulated accident scenarios are 39 estimated using the methodology described in Section 3.4.1. The consequence analysis supports 40 the hazard and accident analyses and control decisions (see Chapter 3.0). The consequence 41 analysis estimates of radiological dose and toxicological exposure to defined receptors requires a 42 “source term.” The source term is a quantity of a specified hazardous material. The material 43 specification must include quantity, physical form, and specific properties of the hazardous 44 material. 45 46
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The methodology for development of radiological source terms (i.e., ULDs) is described in 1 RPP-5924, Radiological Source Terms for Tank Farms Safety Analysis. The ULD is the radiological 2 dose in sieverts (Sv) received by an individual from the inhalation of 1 L of waste. The ULDs for 3 waste transferred to the 242-A Evaporator are calculated using information from sampling of 4 candidate evaporator feed waste or the latest Best-Basis Inventory (BBI) data for the feed waste. 5 6 The methodology for development of toxicological source terms (i.e., USOFs) is described in 7 RPP-30604, Tank Farms Safety Analyses Chemical Source Term Methodology. The USOF is a 8 dimensionless number calculated for waste transferred to the 242-A Evaporator as follows. 9 The concentration of each chemical compound in the waste is divided by the Protective Action 10 Criteria (PAC) for that chemical compound.1 The results from the division for each chemical 11 compound are then summed for the waste to obtain the USOF for the waste. 12 13 The USOFs for waste transferred to the 242-A Evaporator are also calculated using information 14 from sampling of candidate evaporator feed waste or the latest BBI data for the feed waste. 15 16 The ULDs, USOFs, and 90Sr and 137Cs concentrations used in the DSA safety analysis are 17 documented in HNF-IP-1266, Tank Farms Operations Administrative Controls. To protect the 18 ULD, USOF, and 90Sr and 137Cs concentration assumptions in the DSA safety analysis, the 19 following evaluations are required. 20 21
• Evaluation of changes to the PAC. 22 • Evaluation of the 242-A Evaporator feed/slurry. 23
24 Evaluation of Changes to the PAC. PAC are toxicological risk guidelines (i.e., allowable human 25 exposure limits) that are identified for chemical compounds (see Section 3.4.1). The 26 toxicological methodology described in RPP-30604 is dependent on PAC values that are 27 published by the DOE. Because DOE periodically updates the PAC values, they are reviewed 28 annually. If the PAC values have changed, RPP-30604 is revised to incorporate the new PAC 29 values into the toxicological source term methodology. HNF-SD-WM-TSR-006, Tank Farms 30 Technical Safety Requirements, AC 5.9.4, requires that DOE published changes to PAC be 31 incorporated into the toxicological source term methodology at least annually. 32 33 Evaluation of 242-A Evaporator Feed/Slurry. A waste compatibility assessment is developed in 34 accordance with TFC-ENG-CHEM-P-13, Tank Waste Compatibility Assessments, prior to each 35 242-A Evaporator campaign. The waste compatibility assessment evaluates the ULDs, USOFs, 36 and 90Sr and 137Cs concentrations of the 242-A Evaporator feed (i.e., waste transferred to the 37 242-A Evaporator) and the resulting 242-A Evaporator slurry and compares them to the decision 38 rules specified in HNF-SD-WM-OCD-015, Tank Farms Waste Transfer Compatibility Program. 39 The specific decision rules in HNF-SD-WM-OCD-015 that are applicable here are in 40 Section 3.2.2, “AC 5.9.4, Waste Characteristics Controls.” 41 42 If the waste compatibility assessment evaluation identifies the ULD, USOF, 90Sr concentration, 43 or 137Cs concentration of the 242-A Evaporator feed or slurry could exceed the DSA safety 44
1 Protective Action Criteria (PAC) are toxicological risk guidelines (i.e., allowable human exposure limits) that are identified for chemical compounds (see Section 3.4.1).
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analysis assumptions documented in HNF-IP-1266, the waste ULD, USOF, 90Sr concentration, 1 or 137Cs concentration is evaluated to determine if there are required changes to the DSA safety 2 analysis. Required changes to the DSA safety analysis are evaluated in accordance with the 3 TFC-ENG-SB-C-03, Unreviewed Safety Question Process. 4 5 5.5.3.4.3 Functional Requirements. The AC Key Element Waste Characteristics Controls 6 requires protection of DSA safety analysis consequence analysis source term assumptions 7 (i.e., ULDs, USOFs, and 90Sr and 137Cs concentrations). This requires evaluating the ULDs, 8 USOFs, and 90Sr and 137Cs concentrations of the 242-A Evaporator feed and resulting slurry prior 9 to each campaign for required changes to the DSA safety analysis. 10 11 5.5.3.4.4 Key Element Evaluation. The Waste Characteristic Controls AC Key Element 12 ensures that the ULD, USOF, and 90Sr and 137Cs concentration assumptions in the DSA safety 13 analysis are protected. 14 15 DOE publishes PAC values that are used in the evaluation of toxic chemical consequences. The 16 PAC values are used in the RPP-30604 toxicological source term methodology to calculate 17 USOFs. If the published PAC values change, the RPP-30604 toxicological source term 18 methodology is updated. These requirements are implemented by the tank farms TSRs 19 (HNF-SD-WM-TSR-006, AC 5.9.4). 20 21 The DSA safety analysis uses ULDs, USOFs, and 90Sr and 137Cs concentrations to estimate the 22 consequences of postulated accident scenarios. Often, a bounding ULD, USOF, 90Sr 23 concentration, and 137Cs concentration is assumed. Prior to each 242-A Evaporator campaign, 24 the ULDs, USOFs, and 90Sr and 137Cs concentrations of the 242-A Evaporator feed and resulting 25 slurry are evaluated to determine if they could exceed the values in the DSA safety analysis. If 26 there are required DSA safety analysis changes, they are evaluated in accordance with the 27 unreviewed safety question (USQ) process. (Note: If the USQ evaluation is positive, a DSA 28 amendment is processed prior to the 242-A Evaporator campaign.) This ensures that the 242-A 29 Evaporator campaign does not result in waste that is outside of the DSA safety analysis. 30 31 As described above, protection of the ULDs, USOFs, and 90Sr and 137Cs concentrations used to 32 estimate consequences in the DSA safety analysis is ensured by standard engineering processes 33 as captured in referenced procedures. These processes and procedures meet the requirements of 34 the 242-A Evaporator quality assurance program, which meet the requirements of Nuclear 35 Quality Assurance (NQA)-1 (see TFC-PLN-02, Quality Assurance Program Description). 36 Through the identified processes, there is adequate assurance that the ULDs, USOFs, and 90Sr 37 and 137Cs concentrations used in the DSA safety analysis remain valid for 242-A Evaporator 38 operations. 39 40 5.5.3.4.5 Controls (TSRs). Waste Characteristics Controls is a Key Element of an AC 41 (i.e., programmatic AC) with the following requirement. 42 43
Prior to each 242-A Evaporator campaign, the ULDs, USOFs, and 90Sr and 137Cs 44 concentrations of the 242-A Evaporator feed (i.e., waste transferred to the 242-A Evaporator) 45 and the resulting 242-A Evaporator slurry shall be evaluated for required changes to the DSA 46 safety analysis. 47
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1 5.5.3.5 Administrative Control 5.9.5 – Nuclear Criticality Safety. 2 3 5.5.3.5.1 Safety Function. The safety function of the AC Key Element Nuclear Criticality 4 Safety is to ensure that fissile materials operations will be evaluated and documented to 5 demonstrate that operations will be safely sub-critical for all normal and credible abnormal 6 conditions and to ensure that criticality safety controls are implemented. 7 8 5.5.3.5.2 Key Element Description. The criticality safety evaluation report (CSER) for the 9 242-A Evaporator is documented in RPP-7475, Criticality Safety Evaluation Report for Hanford 10 Tank Farms Facilities. RPP-7475 establishes a safe limit on the maximum plutonium 11 concentration for 242-A Evaporator feed solution and requires establishing compliance with this 12 limit prior to each 242-A Evaporator campaign. The limit on evaporator plutonium 13 concentration is implemented via the waste compatibility program. 14 15 5.5.3.5.3 Functional Requirements. The AC Key Element Nuclear Criticality Safety requires 16 that waste transfers to the 242-A Evaporator shall satisfy the controls as identified in RPP-7475. 17 18 5.5.3.5.4 Key Element Evaluation. The Nuclear Criticality Safety AC Key Element ensures 19 that the fissile material operations at the 242-A Evaporator will remain safely sub-critical for 20 normal and credible upset conditions. 21 22 The 242-A Evaporator operations are evaluated in RPP-7475, which demonstrates that the 23 operations will remain safely sub-critical and establishes a criticality safety control on the 24 plutonium concentration in the waste feed to the 242-A Evaporator. 25 26 Prior to waste transfers to the 242-A Evaporator, a waste compatibility assessment is prepared in 27 accordance with TFC-ENG-CHEM-P-13, Tank Waste Compatibility Assessments. The 28 assessment evaluates these waste transfers against the decision rule for criticality safety 29 identified in HNF-SD-WM-OCD-015, Tank Farms Waste Transfer Compatibility Program, 30 Section 3.2.3, “AC 5.9.5, Nuclear Criticality Safety.” The criticality safety decision rule for the 31 242-A Evaporator, which is derived from the CSER is: 32 33
• The Pu concentration of in the 242-A Evaporator feed shall be verified to be less than 34 0.013 g/L by laboratory analysis. 35
36 5.5.3.5.5 Controls (TSRs). Nuclear Criticality Safety is a Key Element of an AC 37 (i.e., programmatic AC) with the following requirement. 38 39
Waste transfers to the 242-A Evaporator shall satisfy the controls as identified in the CSER. 40 41
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5.5.3.6 Administrative Control 5.9.6 – Emergency Preparedness. 1 2 5.5.3.6.1 Safety Function. The safety function of the AC Key Element Emergency 3 Preparedness is to establish emergency preparedness requirements to reduce the risk from the 4 following accidents potentially initiated by a seismic event. 5 6
• Flammable gas accident in the C-A-1 vessel caused by loss of C-A-1 vessel vacuum and 7 purge air flow with waste in the C-A-1 vessel; and flammable gas accident and direct 8 radiation hazard in the process condensate tank TK-C-100 caused by the overflow of 9 waste from the C-A-1 vessel into the process condensate system. 10
11 Note: These accidents potentially initiated by a seismic event are addressed by this 12
AC Key Element until the C-A-1 vessel seismic dump system is upgraded to 13 automatically initiate upon detection of a seismic event (e.g., a seismic switch). 14
15 • Fine spray leak caused by waste slurry transfer piping failure during a waste transfer 16
using slurry pump P-B-2. 17 18
• Waste misroute into the steam condensate weir box TK-C-103 (direct radiation hazard) 19 caused by E-A-1 reboiler tube/tube sheet failure. 20
21 • Waste misroute into the raw water system in uncontrolled areas (chemical burn hazard) 22
caused by backflow prevention device PSV-RW-3 or BFP-RW-11 failure. 23 24 Following a detected seismic event, this AC Key Element requires: 25 26
1. To reduce the risk of a flammable gas accident in the C-A-1 vessel, and a flammable gas 27 accident and direct radiation hazard in process condensate tank TK-C-100, 28
29 − Actuating the C-A-1 vessel seismic dump system, 30 − Stopping the steam to the E-A-1 reboiler, 31 − Shutting down feed pump 241-AW-P-102, 32 − Shutting down air compressors CP-E-1 and CP-E-2, and 33 − Evacuating personnel from the condenser room. 34
35 2. Shutting down slurry pump P-B-2 to reduce the risk of a fine spray leak. 36
37 3. Evacuating personnel from the condenser room to reduce the risk of a direct radiation 38
hazard from the misroute of waste into the steam condensate weir box TK-C-103. 39 40
4. Evacuating untrained personnel from areas that are not radiologically controlled to reduce 41 the risk of a chemical burn hazard (i.e., skin contact with caustic waste) from the 42 misroute of waste into the raw water system in uncontrolled areas. (Note: The pump 43 room, evaporator room, condenser room, and load-out and hot-equipment storage room 44 are radiologically controlled areas.) 45
46 See Section 3.3.2.4.5 for further description of these accidents resulting from a seismic event. 47
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1 5.5.3.6.2 Key Element Description. Seismic events can cause the accidents listed above, 2 because the following safety-significant SSCs that prevent/mitigate or protect facility workers 3 from these accidents are not seismically qualified. 4 5 C-A-1 vessel flammable gas control system (see Section 4.4.1) and C-A-1 vessel waste high 6 level control system (see Section 4.4.2). 7 8
• Pressure relief valve PSV-PB2-1 (see Section 4.4.6). 9 10
• E-A-1 reboiler (see Section 4.4.4). 11 12
• Backflow prevention devices PSV-RW-3 and BFP-RW-11 (see Section 4.4.5). 13 14 Response to a seismic event is governed by TF-ERP-008, Emergency Response Procedure 008 15 Seismic Event Response. Entry into this procedure results from any of the following information 16 being reported to the Central Shift Manager. 17 18 Earth tremors, building movement, office furniture vibrations, etc., are reported to have been 19 observed by enough people to validate the likelihood of an earthquake. 20 21
• Personnel report injury or physical damage to facilities as a result of a perceived 22 earthquake. 23
24 Required initial actions in TF-ERP-008 include actuating the safety-significant C-A-1 vessel 25 seismic dump system (see Section 4.4.3), stopping the steam to the E-A-1 reboiler, shutting 26 down feed pump 241-AW-P-102, shutting down air compressors CP-E-1 and CP-E-2, shutting 27 down slurry pump P-B-2, evacuating personnel from the condenser room, and evacuating 28 untrained personnel from areas that are not radiologically controlled. 29 30 Actuating the C-A-1 vessel seismic dump system, stopping the steam to the E-A-1 reboiler, 31 shutting down feed pump 241-AW-P-102, shutting down air compressors CP-E-1 and CP-E-2, 32 and evacuating personnel from the condenser room are required: 33 34
1. Because of the potential for a flammable gas accident in the C-A-1 vessel following a 35 seismic event if C-A-1 vessel vacuum and purge air are lost with waste in the C-A-1 36 vessel. 37
38 2. Because of the potential for a flammable gas accident and direct radiation hazard in 39
process condensate tank TK-C-100 following a seismic event if waste overflows the 40 C-A-1 vessel into the process condensate system. 41
42 The C-A-1 vessel seismic dump system is actuated via an emergency stop button. Steam to the 43 E-A-1 reboiler is stopped by contacting Johnson Controls, Inc. (JCI) by telephone to request shut 44 down of the low pressure boilers that provide steam to the E-A-1 reboiler. If JCI cannot stop 45 steam to the reboiler, site Electrical Utilities is contacted to isolate power to the 242-A-BA boiler 46 annex. Shutdown of feed pump 241-AW-P-102 and air compressors CP-E-1 and CP-E-2 is 47
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accomplished by isolating electrical power to the 242-A facility (i.e., by disabling the diesel 1 generator and tripping the substation main feed breaker F8X193). If this cannot be accomplished 2 site Electrical Utilities is contacted to isolate power to the 242-A facility. 3 4 Shutting down slurry pump P-B-2 is required because of the potential for a fine spray leak if the 5 seismic event causes failure of the waste slurry transfer piping during a waste transfer using 6 slurry pump P-B-2. Shutdown of slurry pump P-B-2 is also accomplished by isolating electrical 7 power to the 242-A facility. If this cannot be accomplished site Electrical Utilities is contacted 8 to isolate power to the 242-A facility. 9 10 Evacuating personnel from the condenser room is required because of the potential for facility 11 worker direct radiation hazards if the seismic event causes E-A-1 reboiler tube/tube sheet failure 12 and the misroute of waste into the steam condensate weir box TK-C-103. 13 14 Evacuating untrained personnel from areas that are not radiologically controlled is required 15 because of the potential for a chemical burn hazards (i.e., skin contact with caustic waste) if the 16 seismic event fails backflow prevention device PSV-RW-3 or BFP-RW-11 and waste is 17 misrouted into the raw water system in uncontrolled areas. Evacuation of radiologically 18 controlled areas (i.e., pump room, evaporator room, condenser room, and load-out and hot 19 equipment storage room) is not required because only personnel who are trained in SWIM (stop 20 work, warn others, isolate the area, and minimize exposure) actions are allowed in these areas. 21 The frequency of a worker being wetted by a random raw water system leak, while there is waste 22 contaminated raw water ≥ pH 12.5 in the system, and a worker is in the near vicinity of the leak, 23 such that the worker could not take protective actions (e.g., SWIM), is judged to be “beyond 24 extremely unlikely.” In areas that are not radiologically controlled (e.g., heating, ventilation, and 25 cooling [HVAC] room, aqueous makeup [AMU] room) personnel may be present who are not 26 trained to take protective actions. Thus, a waste contaminated raw water leak into these 27 uncontrolled areas could pose a significant facility worker hazard to these untrained personnel 28 (see Section 3.3.2.4.3). 29 30 The notification of personnel in the condenser room and untrained personnel in areas that are not 31 radiologically controlled to evacuate is made via the intercom system (see Section 2.7.4 for 32 additional information on the intercom system) or other alternative methods (e.g., radios, cell 33 phones, direct communication). 34 35 5.5.3.6.3 Functional Requirement. The AC Key Element Emergency Preparedness requires 36 emergency response procedures to: 37 38
• Following seismic events that could cause loss of C-A-1 vessel vacuum and purge air 39 flow or overflow of waste from the C-A-1 vessel into the process condensate system, 40 actuate the C-A-1 vessel seismic dump system, stop the steam to the E-A-1 reboiler, shut 41 down feed pump 241-AW-P-102, shut down air compressors CP-E-1 and CP-E-2, and 42 evacuate personnel from the condenser room. 43
44 • Shut down slurry pump P-B-2 following seismic events that could cause waste slurry 45
transfer piping failure (i.e., a waste leak). 46 47
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• Evacuate personnel from the condenser room following seismic events that could cause 1 E-A-1 reboiler tube/tube sheet failure (i.e., waste misroute into the steam condensate 2 system). 3
4 • Evacuate untrained personnel from areas that are not radiologically controlled following 5
seismic events that could cause backflow prevention device PSV-RW-3 or BFP-RW-11 6 failure (i.e., waste misroute into the raw water system in uncontrolled areas). 7
8 5.5.3.6.4 Key Element Evaluation. The AC Key Element Emergency Preparedness is 9 implemented by the emergency response procedure TF-ERP-008. 10 11 TF-ERP-008 requires actuating the C-A-1 vessel seismic dump system, stopping the steam to the 12 E-A-1 reboiler, shutting down feed pump 241-AW-P-102, shutting down air compressors 13 CP-E-1 and CP-E-2, shutting down slurry pump P-B-2, evacuating the condenser room, and 14 evacuating untrained personnel from areas that are not radiologically controlled in response to a 15 seismic event. The TF-ERP-008 entry requirements are qualitative, but conservatively 16 encompass earthquakes that could cause: 17 18
1. Loss of C-A-1 vessel vacuum and purge air flow and failure of the C-A-1 vessel 19 flammable gas control system; or overflow of waste from the C-A-1 vessel into the 20 process condensate system and failure of the C-A-1 vessel waste high level control 21 system. 22
23 2. Failure of waste slurry transfer piping and pressure relief valve PSV-PB2-1. 24
25 3. Failure of E-A-1 reboiler (i.e., tubes/tube sheet). 26
27 4. Failure of backflow prevention devices PSV-RW-3 and BFP-RW-11. 28
29 The C-A-1 vessel seismic dump system is seismically qualified to operate following the design 30 basis earthquake. However, there are the following issues with the C-A-1 vessel seismic dump 31 system (see Section 4.4.3). 32 33
• The C-A-1 vessel seismic dump system is manually actuated (i.e., before actuating the 34 system the steam to the E-A-1 reboiler and continued operation of recirculation pump 35 P-B-1 may cause the temperature of the waste in the C-A-1 vessel to increase, and 36 continued operation of feed pump 241-AW-P-102 may cause the overflow of waste from 37 the C-A-1 vessel into the process condensate system). 38
39 • There are postulated post-seismic event fires that could cause failure of the C-A-1 vessel 40
seismic dump system to meet its safety function. 41 42 There is a planned improvements to address these issues (i.e., an upgrade of the C-A-l seismic 43 dump system to automatically initiate upon detection of a seismic event - see Section 3.3.2.3.5). 44 Until completion of this planned improvement, the emergency response actions of manually 45 actuating the C-A-1 vessel seismic dump system, shutting down feed pump 241-AW-P-102, 46 shutting down air compressors CP-E-1 and CP-E-2, and evacuating personnel from the 47
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condenser room minimizes the risk of a flammable gas accident in the C-A-1 vessel and a 1 flammable gas accident and direct radiation hazard in process condensate tank TK-C-100. 2 (Note: Evacuating personnel from the condenser room is the same emergency response action 3 required following seismic events that could cause E-A-1 reboiler tube/tube sheet failure.) 4 5 The seismically qualified emergency stop button (HS-CA1-1) is located on the external, 6 southeast wall of the 242-A Building and is readily accessible to personnel. (Note: There are 7 two other emergency stop buttons in the control room located on walls adjacent to the entrance 8 and exit doors, but the control room is not a seismically qualified structure.) 9 10 Contacting JCI to stop the steam to the E-A-1 reboiler at the 242A-BA boiler annex is done by 11 telephone. During 242-A Evaporator operation JCI personnel are normally present at the 12 242A-BA boiler annex. If the 242A-BA boiler annex can be safely entered following the seismic 13 event, the low pressure boiler can be quickly shut down. If JCI cannot stop steam to the reboiler, 14 site Electrical Utilities is contacted to isolate power to the 242-BA boiler annex. Stopping steam 15 to the E-A-1 reboiler limits the C-A-1 vessel waste temperature increase if the seismic event 16 does not otherwise cause loss of steam to the E-A-1 reboiler or opening of the fail-safe feed 17 valve HV-CA1-1 or dump valves HV-CA1-7 and HV-CA1-9 to drain/dump waste from the 18 C-A-1 vessel. (Note: While there may be other methods for stopping steam to the E-A-1 19 reboiler, their implementation may impose potential hazards to worker safety following the 20 seismic event.) 21 22 Shutting down feed pump 241-AW-P-102 prevents or minimizes the overflow of waste from the 23 C-A-1 vessel into process condensate tank TK-C-100 if the seismic event does not otherwise 24 cause shutdown of the feed pump. Securing electrical power to the feed pump may, however, be 25 prevented or delayed if there are potential hazards to worker safety following the seismic event. 26 27 (Note: Shutting down recirculation pump P-B-1 is not included as a required emergency action 28 because the heat input from recirculation pump P-B-1 operation is small relative to steam to the 29 E-A-1 reboiler.) 30 31 Shutting down air compressors CP-E-1 and CP-E-2, and the subsequent venting of air from feed 32 valve HV-CA1-1, should drain the C-A-1 vessel and leave approximately 2,700 gal of waste in 33 the C-A-1 vessel. (Note: Although not seismically qualified, dump valves HV-CA1-7 and 34 HV-CA1-9 may also open and completely drain the C-A-1 vessel by shutting down the air 35 compressors and venting air from these valves.) Even if the 2,700 gal of residual waste in the 36 C-A-1 vessel is at 230°F because of continued steam flow to the E-A-1 reboiler, the flammable 37 gas concentration in the C-A-1 vessel is not expected to reach 100% of the LFL based on the 38 analysis in RPP-CALC-29700, Flammability Analysis and Time to Reach Lower Flammability 39 Limit Calculations for the 242-A Evaporator. The analysis in RPP-CALC-29700 shows that 40 with 2,700 gallons of residual waste in the C-A-1 vessel at 230°F, it takes more than a week to 41 reach 100% of the LFL. During this time the residual waste will cool (see RPP-CALC-57389, 42 242-A Evaporator 28" Recirculation Line Cooling Analysis). The RPP-CALC-29700 analysis 43 also shows that as the waste cools, the flammable gas generation rate decreases and, therefore, 44 the time to 100% of the LFL increases. Based on the estimated cooling rate and the increasing 45 time to reach 100% of the LFL as the waste cools, it is qualitatively judged that the flammable 46 gas concentration in the C-A-1 vessel does not reach 100% of the LFL. In addition, 47
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RPP-CALC-29700 shows that at a waste temperature of 160°F, barometric breathing is sufficient 1 to prevent reaching 100% of the LFL, and it takes more than 6 months to reach 100% of the LFL 2 assuming zero ventilation. Because several different actions can be readily implemented to 3 ensure barometric breathing of the C-A-1 vessel (e.g., operate the vessel ventilation system, 4 provide purge air flow, open a ventilation path to the C-A-1 vessel), the 2,700 gallons of residual 5 waste in the C-A-1 vessel is not a flammable gas hazard (i.e., the flammable gas concentration in 6 the C-A-1 vessel will not reach 100% of the LFL). 7 8 The intercom system at the 242-A Evaporator is located in radiologically controlled and 9 uncontrolled areas (specific locations are identified in Section 2.7.4). The equipment used to 10 shut down feed pump 241-AW-P-102, air compressors CP-E-1 and CP-E-2, and slurry pump 11 P-B-2, and the intercom system used to notify personnel to evacuate the condenser room, and 12 from the areas that are not radiologically controlled, are not classified as safety significant. The 13 operability of the controls for shutting down feed pump 241-AW-P-102, air compressors CP-E-1 14 and CP-E-2, and slurry pump P-B-2, and the intercom system is ensured by their use for the 15 normal shutdown of feed pump 241-AW-P-102, air compressors CP-E-1 and CP-E-2, and slurry 16 pump P-B-2, and when personnel are working in the areas with intercoms, respectively. In 17 addition, alternative methods for shut down of the feed pump 241-AW-P-102, air compressors 18 CP-E-1 and CP-E-2, and slurry pump P-B-2 (i.e., isolating power to the pump or air 19 compressors) or notifying personnel to evacuate (e.g., radios, cell phones, direct communication) 20 are available if the feed pump 241-AW-P-102, air compressors CP-E-1 and CP-E-2, or slurry 21 pump P-B-2 shutdown controls and intercom system are unavailable following the seismic event. 22 23 As described in Chapter 15.0, “Emergency Preparedness Program,” training is provided on 24 emergency response procedures and emergency response actions. The training includes 25 emergency response procedure TF-ERP-008 and its emergency response actions. In addition, 26 drills are periodically conducted and the drill scenarios cover a range of events including natural 27 phenomena events (e.g., seismic events). 28 29 5.5.3.6.5 Controls (TSRs). Emergency Preparedness is a Key Element of an Administrative 30 Control (i.e., programmatic AC) with the following requirements that are applicable in the 31 Operation Mode. 32 33
1. Emergency response procedures shall include the following actions following seismic 34 events that could cause loss of C-A-1 vessel vacuum and purge air flow, or overflow of 35 waste from the C-A-1 vessel into the process condensate system. 36
37 − Actuating the C-A-1 vessel seismic dump system. 38 − Stopping the steam to the E-A-1 reboiler. 39 − Shutting down feed pump 241-AW-P-102. 40 − Shutting down air compressors CP-E-1 and CP-E-2. 41 − Evacuating personnel from the condenser room. 42
43 2. Emergency response procedures shall include shutting down slurry pump P-B-2 44
following seismic events that could cause waste slurry transfer piping failure (i.e., a waste 45 leak). 46
47
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3. Emergency response procedures shall include evacuating personnel from the condenser 1 room following seismic events that could cause E-A-1 reboiler tube/tube sheet failure 2 (i.e., waste misroute into the steam condensate system). 3
4 4. Emergency response procedures shall include evacuating untrained personnel from areas 5
that are not radiologically controlled following seismic events that could cause backflow 6 prevention device PSV-RW-3 or BFP-RW-11 failure (i.e., waste misroute into the raw 7 water system in uncontrolled areas). 8
9 Because backflow prevention device BFP-RW-11 is required to be operable in the Limited 10 Waste Mode (see Section 4.4.5), AC Key Element Requirement 4 is also applicable in the 11 Limited Waste Mode, except when backflow prevention device BFP-RW-11 is removed from 12 the raw water line (i.e., an air gap). (Note: Applicability in the Limited Waste Mode results 13 because a waste misroute into the raw water system in uncontrolled areas caused by failure of 14 backflow prevention device BFP-RW-11 is possible in the Limited Waste Mode. See 15 Section 4.4.5.) 16 17 5.5.3.7 Administrative Control 5.6 – Safety Management Programs. 18 19 5.5.3.7.1 Purpose. This AC includes commitments to maintain SMPs as part of the TOC safety 20 management system. 21 22 In addition to the SACs and Key Elements of ACs, defense-in-depth is provided by SMPs. 23 24 5.5.3.7.2 Derivation Criteria. SMPs are identified to provide defense-in-depth over a wide 25 range of hazardous conditions and postulated accident scenarios, as well as normal, abnormal, 26 and emergency conditions. Additionally, within the control derivation and evaluation for SACs 27 and Design Features in Chapter 4.0, SMPs were explicitly or implicitly identified that ensure the 28 identified SACs and Design Features are properly implemented and maintained. 29 30 5.5.3.8 Administrative Control 5.10.1 – Reserved for Future Use. 31 32 5.5.3.9 Administrative Control 5.10.2 – Emergency Response Actions Following 33 Facility Fires. 34
35 5.5.3.9.1 Safety Function. The safety function of the AC Emergency Response Actions 36 Following Facility Fires is to ensure the safe shutdown of the 242-A Evaporator following fires. 37 Ensuring the safe shutdown of the 242-A Evaporator following fires reduces the risk from the 38 following accidents potentially initiated by a fire. 39 40
• Flammable gas accident in the C-A-1 vessel caused by loss of C-A-1 vessel vacuum and 41 purge air flow with waste in the C-A-1 vessel (see Section 3.3.2.4.1). 42
43 • Flammable gas accident and direct radiation hazard in process condensate tank TK-C-100 44
caused by an overflow of waste from the C-A-1 vessel into the process condensate 45 system (see Section 3.3.2.4.1 and Section 3.3.2.4.3). 46
47
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Note: This AC is required until completion of a planned design improvement that ensures the 1 C-A-1 vessel flammable gas control system and the C-A-1 vessel waste high level control 2 system fail safe in the event of a facility fire (see Section 4.4.1 and Section 4.4.2). 3
4 5.5.3.9.2 Key Element Description. Facility fires may cause the accidents listed above, 5 because the following safety-significant structures, systems, and components (SSC) that prevent 6 these accidents may experience unsafe failures due to fires. 7 8
• C-A-1 vessel flammable gas control system (see Section 4.4.1). 9 • C-A-1 vessel waste high level control systems (see Section 4.4.2). 10
11 Following a fire that could cause failure of the C-A-1 vessel flammable gas control system or the 12 C-A-1 waste high level control system, the AC Emergency Response Actions Following Facility 13 Fires requires: 14
15 1. Press an emergency stop button within 40 min. 16
17 AND 18
19 2a. Verify the waste level in DST 241-AW-102 has increased by > 7 in. within 12 hours. 20
21 OR 22
23 2b. Shut down air compressors CP-E-1 and CP-E-2 within 12 hours. 24
25 Response to a facility fire is governed by TF-ERP-EVAP-006, 242-A Evaporator Fire. Entry 26 into this procedure results from: 27 28
• A confirmed fire identified by smoke or flame. 29 • Fire alarm is actuated. 30
31 TF-ERP-EVAP-006 requires evacuation of the 242-A Evaporator and pressing an emergency 32 stop button (seismic shutdown button) as an initial action (i.e., in less than 40 min). The Hanford 33 Fire Department response time to a fire at the 242-A Evaporator is estimated at 10 min. 34 Dependent on the fire investigation by the Hanford Fire Department, if a fire is confirmed that 35 could have caused failure of the C-A-1 vessel flammable gas control system or the C-A-1 waste 36 high level control system, and if it cannot be verified that the C-A-1 vessel has been drained via 37 feed valve HV-CA1-1 or emptied via dump valves HV-CA1-7 and HV-CA1-9 (i.e., > 7 in. waste 38 level increase in DST 241-AW-102), air compressors CP-E-1 and CP-E-2 are shut down within 39 12 hours of detecting the fire. Shutting down the air compressors, and the subsequent venting of 40 the air from feed valve HV-CA1-1, opens the feed valve (and dump valves HV-CA1-7 and 41 HV-CA1-9 if their actuators in the condenser room have not been damaged by the fire). This 42 places the 242-A Evaporator in a safe and stable condition. 43 44
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5.5.3.9.3 Functional Requirement. The functional requirements of AC Emergency Response 1 Actions Following Facility Fires are as follows. 2 3
1. Prevent the overflow of waste from the C-A-1 vessel into the process condensate system 4 by either stopping waste feed (stop feed pump 241-AW-P-102-1) or by emptying the 5 C-A-1 vessel (open dump valves HV-CA1-7 and HV-CA1-9) within 40 min. 6
7 2. For fire scenarios that may prevent steam isolation valve HV-EA1-5 from closing, either 8
begin draining waste from the C-A-1 vessel (stop feed pump 241-AW-P-102-1 and open 9 feed valve HV-CA1-1) or empty waste from the C-A-1 vessel (open dump valves 10 HV-CA1-7 and HV-CA1-9) within 1.9 hours to prevent a flammable gas accident in the 11 C-A-1 vessel. 12
13 3. For fire scenarios that do not prevent steam isolation valve HV-EA1-5 from closing, 14
either drain waste from the C-A-1 vessel (stop feed pump 241-AW-P-102-1 and open 15 feed valve HV-CA1-1) or empty waste from the vessel (open dump valves HV-CA1-7 16 and HV-CA1-9) within 24 hr. 17
18 At least 40 min is available to prevent the overflow of waste from the C-A-1 vessel into the 19 process condensate system (see Section 4.4.2.4). This can be accomplished by stopping feed 20 pump 241-AW-P-102-1 or opening dump valves HV-CA1-7 and HV-CA1-9. 21 22 Based on the evaluation in RPP-CALC-29700, Flammability Analysis and Time to Reach Lower 23 Flammability Limit Calculations for the 242-A Evaporator, it takes at least 1.9 hours to reach 24 25% of the LFL assuming a waste temperature of 230oF (assumes that steam isolation valve 25 HV-EA1-5 does not close) with 26,000 gal of waste in the C-A-1 vessel. (Note: This evaluation 26 conclusion is protected by AC Key Element C-A-1 Vessel Time to Lower Flammability Limit [see 27 Section 5.5.3.1]). Opening dump valves HV-CA1-7 and HV-CA1-9 eliminates the C-A-1 vessel 28 flammable gas hazard. Draining the vessel through feed valve HV-CA1-1 leaves approximately 29 2,700 gallon of residual waste in the C-A-1 vessel. Analysis in RPP-CALC-29700 shows that with 30 2,700 gallons of residual waste in the C-A-1 vessel at 230°F, it takes more than a week to reach 31 100% of the LFL. During this time the residual waste will cool (see RPP-CALC-57389). The 32 RPP-CALC-29700 analysis also shows that as the waste cools, the flammable gas generation rate 33 decreases and, therefore, the time to 100% of the LFL increases. Based on the estimated cooling 34 rate and the increasing time to reach 100% of the LFL as the waste cools, it is qualitatively judged 35 that the flammable gas concentration in the C-A-1 vessel will not reach 100% of the LFL. In 36 addition, RPP-CALC-29700 shows that at a waste temperature of 160°F, barometric breathing is 37 sufficient to prevent reaching 100% of the LFL, and it takes more than 6 months to reach 100% of 38 the LFL assuming zero ventilation. Because several different actions can be readily implemented 39 to ensure barometric breathing of the C-A-1 vessel (e.g., operate the vessel ventilation system, 40 provide purge air flow, open a ventilation path to the C-A-1 vessel), the 2,700 gallons of residual 41 waste in the C-A-1 vessel is not a flammable gas hazard (i.e., the flammable gas concentration in 42 the C-A-1 vessel will not reach 100% of the LFL). 43 44 Based on the evaluation in RPP-CALC-29700, it takes at least 24 hours to reach 25% of the LFL 45 at a waste temperature of 160oF (assumes that steam isolation valve HV-EA1-5 closes) with 46 26,000 gal of waste in the C-A-1 vessel. (Note: This evaluation conclusion is protected by 47
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AC Key Element C-A-1 Vessel Time to Lower Flammability Limit [see Section 5.5.3.1]). For 1 this fire scenario, opening feed valve HV-CA1-1 or dump valves HV-CA1-7 and HV-CA1-9 2 eliminates the C-A-1 vessel flammable gas hazard. 3 4 5.5.3.9.4 AC Evaluation. The AC Emergency Response Actions Following Facility Fires is 5 implemented by the emergency response procedure TF-ERP-EVAP-006. The actions required to 6 achieve safe shutdown for postulated facility fires is documented in RPP-TE-57362, Evaluation 7 of Facility Shutdown after a Fire in the 242-A Evaporator. The evaluation in RPP-TE-57362 8 considers if the fire can initiate an accident(s), equipment required for shutdown that might fail 9 due to the fires (unsafe failures), and equipment that would be available to achieve safe 10 shutdown (see functional requirements above). The results of the evaluation are summarized in 11 Table 5.5.3-1, Emergency Response Actions Following Facility Fires. Because the 12 location/extent of a fire may not be immediately known, the AC requires actions that address all 13 functional requirements for all postulated facility fires (i.e., press an emergency stop button 14 within 40 min, and if C-A-1 vessel has not been verified to have drained or dumped, shut down 15 air compressors CP-E-1 and CP-E-2 within 12 hours). 16 17 TF-ERP-EVAP-006 requires and emergency stop button (seismic shutdown button) be pressed 18 as an initial action to a fire if there is waste in the vessel. There are three emergency stop 19 buttons. HS-CA1-1, located on the external, southeast wall of the 242-A Building, and access is 20 not limited by a facility fire. The two other emergency stop buttons are located inside the control 21 room on walls adjacent to the 242-AB Building control room entrance (south) and exit (north-22 east) doors. These buttons could also be readily pressed by operators when evacuating the 23 control room. Therefore, there is reasonable assurance that this action is completed within 24 40 min. In addition, as an initial action, TF-ERP-EVAP-006 requires that if a waste level 25 increase of >7 in. in DST 241-AW-102 cannot be verified within 30 minutes, that air 26 compressors CPE-E-1 and CP-E-2 be shutdown. Therefore, there is a reasonable assurance that 27 this action can be completed within 12 hours. 28 29 Draining or emptying the C-A-1 vessel results in a DST 241-AW-102 waste level increase of at 30 least 7 in. The 7 in. waste level increase in DST 241-AW-102 is based on the minimum normal 31 operating C-A-1 waste level (normal operating range is 23,500 gal to 25,500 gal) minus the 32 2,700 gal residual waste left in the C-A-1 vessel if only feed valve HV-CA1-1 opens, divided by 33 2,750 gal per inch (i.e., [23,500 gal – 2,700 gal]/2,750 gal/in. > 7.0 in). DST 241-AW-102 waste 34 level information can be obtained from the tank monitor and control system (TMACS) (see 35 RPP-13033, Tank Farms Documented Safety Analysis, Section 2.5.8, “Waste Surveillance 36 Activities”). 37 38 The air compressors can be shut down by isolating power to the facility. This can be 39 accomplished by disabling the diesel generator and tripping the substation main feed breaker 40 (F8X193). The diesel generator control switch and breaker F8X193 are located outside of the 41 facility, and, therefore, access is not limited by the fire. With shut down of the air compressors, 42 and subsequent venting of the compressed air from feed valve HV-CA1-1, the feed valve opens. 43 (Note: If the fire has not damaged the dump valve HV-CA1-7 and HV-CA1-9 actuators, these 44 valves also open.) RPP-TE-57362 has evaluated the compressor air system and concluded that 45 by shutting off the air compressors, compressed air is vented and the feed valve will open. 46 Based on operating experience the feed valve opens in not more than a few hours of shutting off 47
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the air compressors, providing reasonable assurance that the C-A-1 vessel will drain within 24 hr 1 of the fire. 2 3 As described in Chapter 15.0, “Emergency Preparedness Program,” training is provided on 4 emergency response procedures and emergency response actions. The training includes 5 emergency response procedure TF-ERP-EVAP-006 and its emergency response actions. In 6 addition, drills are periodically conducted and the drill scenarios cover a range of events 7 including facility fires. 8 9 5.5.3.9.5 Controls (TSRs). Emergency Response Actions Following Facility Fires is an AC 10 that is required until completion of a planned design improvement that ensures the C-A-1 vessel 11 flammable gas control system and the C-A-1 vessel waste high level control system fail safe in 12 the event of a facility fire. The AC is applicable in the Operation Mode. The AC requirements 13 are: 14 15 Following facility fires that could cause failure of the C-A-1 vessel flammable gas control 16 system or the C-A-1 vessel waste high level control system: 17 18
1. Press an emergency stop button within 40 min. 19 20
AND 21 22
2a. Verify the waste level in DST 241-AW-102 has increased by > 7 in. within 12 hours. 23 24
OR 25 26
2b. Shut down air compressors CP-E-1 and CP-E-2 within 12 hours. 27 28 29 5.6 DESIGN FEATURES 30 31 Design Features means the design features of a nuclear facility listed in the TSRs that, if altered 32 or modified, would have a significant effect on safe operation. Design Features are developed in 33 Chapter 4.0. The Design Features for the 242-A Evaporator are listed below. 34 35
42 • Design Feature 6.4 – 242-A Building (see Section 4.4.7). 43
44 The safety function, system description, functional requirements, system evaluation, and controls 45 for the above Design Features are described in the referenced Chapter 4.0 section. 46 47
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1 5.7 INTERFACES WITH TECHNICAL SAFETY REQUIREMENTS FROM OTHER 2
FACILITIES 3 4 The 242-A Evaporator interfaces physically and administratively with the tank farms and other 5 Hanford Site facilities and operations. This section identifies TSRs from the tank farms and 6 other facilities and operations that affect the 242-A Evaporator safety basis. 7 8 The only Hazard Category 2 or 3 facilities that interface with the 242-A Evaporator are the tank 9 farm facilities. Waste (feed) is received from the tank farms and evaporated waste (slurry) is 10 returned to the tank farms. The tank farm facilities are operated by the TOC but have an 11 independent DSA (RPP-13033, Tank Farms Documented Safety Analysis) and TSRs 12 (HNF-SD-WM-TSR-006, Tank Farms Technical Safety Requirements). 13 14 The fire protection program and emergency preparedness program are identified as important 15 elements of the 242-A Evaporator safety basis. Both of these programs are dependent on other 16 Hanford Site facilities and organizations. Chapter 15.0 describes the TOC emergency 17 preparedness program and its interfaces with the Hanford Emergency Management Plan and 18 links to DOE, state, and local offsite organizations. The TOC fire protection program and its 19 interfaces with the Hanford Fire Department are described in Chapter 11. 20 21 22 5.7.1 Tank Farms 23 24 The 242-A Evaporator receives waste (feed) from the tank farms (via double-shell tank [DST] 25 241-AW-102) and returns waste (slurry) to the tanks farms (DSTs in the 200 East Area). 26 Minimum staffing levels may be shared between the tank farms and the 242-A Evaporator as 27 addressed in Section 5.4.2. Interface and coordination of TSRs between the tank farms and the 28 242-A Evaporator is accomplished through the SMPs and USQ process. 29 30 Tank farm operations can affect the 242-A Evaporator by inadvertently routing waste to the 31 242-A Evaporator in a misroute. SAC Evaporator and Pump Room Access and Pump Room 32 Cover Block Control (see Section 4.5.5) restricts access to the evaporator room and pump room 33 and requires the pump room cover blocks to be in place when waste could be misrouted to the 34 242-A Evaporator from tank farms. 35 36 242-A Evaporator operations can cause hazards in the tank farms including waste transfer leaks 37 during waste transfers (including gravity flow) from the 242-A Evaporator into the tank farms. 38 These postulated accidents are identified and evaluated in RPP-13033. Controls to prevent or 39 mitigate waste transfer leak accidents in the tank farms apply when slurry pump P-B-2 (used to 40 transfer waste from the 242-A Evaporator to the tank farms) is active and not under 41 administrative lock or when the 242-A Evaporator C-A-1 vessel contains waste. 42 43 To protect the radiological and toxicological material source terms used in the 242-A Evaporator 44 accident analysis, as well as the tank farms accident analysis, waste transfers to and from the 45 242-A Evaporator are subject to AC 5.9.4, “Waste Characteristics Controls,” in the 242-A 46
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Evaporator TSRs (see Section 5.5.3.4) as well as AC 5.9.4, “Waste Characteristics Controls,” in 1 the tank farm TSRs (see RPP-13033, Section 5.5.3.4). 2 3 AC 5.9.1, “C-A-1 Vessel Time to Lower Flammability Limit,” in the 242-A Evaporator TSRs 4 (see Section 5.5.3.1) protects the 242-A Evaporator safety analysis input regarding waste 5 flammable gas generation rates and time to the LFL for waste received from the tank farms. 6 7 AC 5.9.5, “Nuclear Criticality Safety,” in the 242-A Evaporator TSRs (see Section 5.5.3.5) 8 requires that waste transfers to the 242-A Evaporator satisfy the controls as identified in the 9 CSER. 10 11 12 5.8 REFERENCES 13 14 10 CFR 830, “Nuclear Safety Management,” Office of the Federal Register (FR 1810, Vol. 66, 15
No. 7), January 10, 2001. 16 17 ARP-T-601-400, Respond to SIS Graphic #400 Alarms at the 242-A Evaporator, as amended, 18
Washington River Protection Solutions LLC, Richland, Washington. 19 20 DOE G 421.1-2, 2001, Implementation Guide for Use in Developing Documented Safety 21
Analyses to Meet Subpart B of 10 CFR 830, U.S. Department of Energy, Washington, 22 D.C. 23
24 DOE G 423.1-1, 2001, Implementation Guide for Use in Developing Technical Safety 25
Requirements, U.S. Department of Energy, Washington, D.C. 26 27 DOE-STD-1186-2004, 2004, Specific Administrative Controls, U.S. Department of Energy, 28
Washington, D.C. 29 30 DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor 31
Nuclear Facility Documented Safety Analyses, Change Notice No. 3, U.S. Department of 32 Energy, Washington, D.C. 33
34 HNF-15279, 242-A Evaporator Technical Safety Requirements, as amended, Washington River 35
Protection Solutions LLC, Richland, Washington. 36 37 HNF-IP-1266, Tank Farms Operations Administrative Controls, as amended, Washington River 38
Protection Solutions LLC, Richland, Washington. 39 40 HNF-SD-WM-OCD-015, Tank Farms Waste Transfer Compatibility Program, as amended, 41
Washington River Protection Solutions LLC, Richland, Washington. 42 43 HNF-SD-WM-TSR-006, Tank Farms Technical Safety Requirements, as amended, Washington 44
River Protection Solutions LLC, Richland, Washington. 45 46
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NFPA 70, National Electrical Code, National Fire Protection Association, Quincy, 1 Massachusetts. 2
3 NFPA 497, Recommended Practice for the Classification of Flammable Liquids, Gases, or 4
Vapors and of Hazardous (Classified) Locations for Electrical Installations in Chemical 5 Process Areas, National Fire Protection Association, Quincy, Massachusetts. 6
7 RPP-5924, 2007, Radiological Source Terms for Tank Farms Safety Analysis, Rev. 5, CH2M 8
HILL Hanford Group, Inc., Richland, Washington. 9 10 RPP-7475, Criticality Safety Evaluation Report for Hanford Tank Farms Facilities, as amended, 11
Washington River Protection Solutions LLC, Richland, Washington. 12 13 RPP-13033, Tank Farms Documented Safety Analyses, as amended, Washington River 14
Protection Solutions LLC, Richland, Washington. 15 16 RPP-30604, Tank Farms Safety Analyses Chemical Source Term Methodology, as amended, 17
Washington River Protection Solutions LLC, Richland, Washington. 18 19 RPP-CALC-29700, 2014, Flammability Analysis and Time to Reach Lower Flammability Limit 20
Calculations for the 242-A Evaporator, Rev. 3, Washington River Protection Solutions 21 LLC, Richland, Washington. 22
Washington River Protection Solutions LLC, Richland, Washington. 25 26 RPP-RPT-58290, NFPA Flammable Vapor and Gas Hazard Classification for the 242-A 27
Evaporator, as amended, Washington River Protection Solutions LLC, Richland, 28 Washington. 29
30 RPP-TE-57362, 2014, Evaluation of Facility Shutdown After a Fire in the 242-A Evaporator, 31
Rev. 0, Washington River Protection Solutions LLC, Richland, Washington. 32 33 TF-ERP-EVAP-006, 242-A Evaporator Fire, as amended, Washington River Protection 34
Washington River Protection Solutions LLC, Richland, Washington. 38 39 TFC-ENG-CHEM-P-13, Tank Waste Compatibility Assessments, as amended, Washington River 40
Protection Solutions LLC, Richland, Washington. 41 42 TFC-ENG-FACSUP-P-17, Flammable Gas Activities Ignition Source Control, as amended, 43
Washington River Protection Solutions LLC, Richland, Washington. 44 45 TFC-ENG-SB-C-03, Unreviewed Safety Questions Process, as amended, Washington River 46
1 TFC-ENG-STD-13, Ignition Source Controls for Potentially Flammable Atmospheres, as 2
amended, Washington River Protection Solutions LLC, Richland, Washington. 3 4 TFC-ENG-STD-45, Design and Installations for Potentially Flammable Atmospheres, as 5
amended, Washington River Protection Solutions LLC, Richland, Washington. 6 7 TFC-PLN-02, Quality Assurance Program Description, as amended, Washington River 8
Protection Solutions LLC, Richland, Washington. 9 10 TO-600-030, Start Up 242-A Evaporator System, as amended, Washington River Protection 11
TSR control # TSR control title Applicable DSA Sections LCO 3.1 C-A-1 Vessel Flammable Gas Control System • Flammable Gas Accidents (3.3.2.4.1) LCO 3.2 C-A-1 Vessel Waste High Level Control System • Flammable Gas Accidents (3.3.2.4.1)
• Waste Leaks and Misroutes (3.3.2.4.3) LCO 3.3 C-A-1 Vessel Seismic Dump System • Natural events (Section 3.3.2.4.5) AC 5.6 Safety Management Programs • Defense-in-Depth (3.3.2.3.2). The features of the SMPs that provide
defense-in-depth are captured in Chapter 17. AC 5.7 Reserved for Future Use • -- AC 5.8.1 Flammable Gas Controls for Waste Feed Transfer Piping,
Waste Slurry Transfer Piping, and C-A-1 Vessel Drain (Dump) Piping
• Flammable Gas Accidents (3.3.2.4.1)
AC 5.8.2 Evaporator and Pump Room Access and Pump Room Cover Block Control
• Waste Leaks and Misroutes (3.3.2.4.3)
AC 5.8.3 Evaporator and Pump Room Transient Combustible Material Controls
• Flammable Gas Accidents (3.3.2.4.1) • Waste Leaks and Misroutes (3.3.2.4.3)
AC 5.9.1 C-A-1 Vessel Time to Lower Flammability Limit • Flammable Gas Accidents (3.3.2.4.1) AC 5.9.2 Ignition Controls • Flammable Gas Accidents (3.3.2.4.1) AC 5.9.3 Reserved for Future Use • -- AC 5.9.4 Waste Characteristics Controls • Initial Condition (3.3.2.4) AC 5.9.5 Nuclear Criticality Safety • Prevention of Inadvertent Criticality (6.0) AC 5.9.6 Emergency Preparedness • Natural events (Section 3.3.2.4.5) AC 5.10.1 Reserved for Future Use • -- AC 5.10.2 Emergency Response Actions Following Facility Fires • Flammable Gas Accidents (3.3.2.4.1)
• Waste Leaks and Misroutes (3.3.2.4.3) DF 6.1 E-A-1 Reboiler • Flammable Gas Accidents (3.3.2.4.1)
• Waste Leaks and Misroutes (3.3.2.4.3 DF 6.2 Backflow Prevention Devices (PSV-RW-3 and BFP-RW-11) • Flammable Gas Accidents (3.3.2.4.1)
• Waste Leaks and Misroutes (3.3.2.4.3) 2
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Table 5.3.1-1. Technical Safety Requirement Controls Cross-Reference with Applicable Accidents. (2 sheets) TSR control # TSR control title Applicable DSA Sections
S2 high waste temperature trip, steam isolation valve, feed pump contactor, recirculation pump contactor; S3 (except feed valve solenoid) Notes: S2 high waste temperature trip closes the steam isolation valve and stops the feed pump and recirculation pump if waste temperature is increasing. S3 stops the feed pump.
Actuate S3 (press an emergency stop button) within 40 min. If vessel has not drained or emptied, shut down air compressors CP-E-1 and CP-E-2 within 12 hours.
AMU/HVAC rooms Neither Feed valve, dump valves, MCS shutdown functions Note: MCS shutdown function (open dump valves) is initiated when S3 is actuated (HS-CA1-1 is pressed)
Actuate S3 (press an emergency stop button) within 40 min. If vessel has not drained or emptied, shut down air compressors CP-E-1 and CP-E-2 within 12 hours.
LIST OF TERMS 1 2 3 ANS American Nuclear Society 4 ANSI American National Standards Institute 5 CSER criticality safety evaluation report 6 CSP Criticality Safety Program 7 DOE U. S. Department of Energy 8 Pu Plutonium 9
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6.0 PREVENTION OF INADVERTENT CRITICALITY 1 2 3 6.1 INTRODUCTION 4 5 This chapter describes the specifics of how the Criticality Safety Program (CSP) is implemented 6 to ensure the criticality safety of the minor fissile inventories processed through the 242-A 7 Evaporator. The CSP is established to ensure the criticality safety of operations at tank farms 8 facilities as required by Department of Energy (DOE) O 420.1C, Facility Safety. The tank farms 9 CSP is documented in TFC-PLN-49, Criticality Safety Program. While this chapter discusses 10 only the details of how criticality safety is addressed at the 242-A Evaporator, Chapter 6.0 of 11 RPP-13033, Tank Farms Documented Safety Analysis, provides a summary description of the 12 overall CSP for the tank farms facilities. 13 14 The criticality safety of the 242-A Evaporator is evaluated in the Criticality Safety Evaluation 15 Report (CSER), RPP-7475, Criticality Safety Evaluation Report for Hanford Tank Farms 16 Facilities, as required by DOE O 420.1C. The CSER concludes that the fissile material 17 operations at the 242-A Evaporator will remain safely sub-critical for all normal and credible 18 upset conditions. 19 20 21 6.2 REQUIREMENTS 22 23 DOE O 420.1C provides the requirements for demonstrating the criticality safety of fissile 24 material operations at DOE facilities. A fundamental criticality safety requirement is that such 25 operations shall be demonstrated to be safely sub-critical for normal and credible upset 26 conditions. DOE O 420.1C directs that the CSP follow numerous standards on criticality safety 27 from DOE and American National Standards Institute (ANSI)/American Nuclear Society (ANS). 28 These standards are described more fully in RPP-13033 (Chapter 6) and TFC-PLN-49. 29 DOE O 420.1C directs that the criticality safety requirements are applicable for fissile material 30 operations that involve, or potentially involve, fissile materials in quantities that exceed certain 31 limits, such as those listed in ANSI/ANS-8.1-2014, Nuclear Criticality Safety in Operations with 32 Fissionable Materials Outside Reactors. Thus, based on the sub-critical limits from 33 ANSI/ANS-8.1-2014, the requirements of DOE O 420.1C apply when fissile material operations 34 involve, for example, more than 450 g of fissile plutonium (Pu). 35 36 37 6.3 CRITICALITY CONCERNS 38 39 The primary criticality safety concern in the 242-A Evaporator arises with the minor inventory of 40 fissile material that arrives in the evaporator feed supernate. However, concern with this fissile 41 material is limited because the maximum Pu concentration in the supernatant of any tank at the 42 tank farms is only about 0.0007 g/L (RPP-7475, Section 5.4). The Pu concentration in the 43 supernate is limited by the alkalinity maintained in the tanks, which ensures a low solubility of 44 Pu in the evaporator feed material (RPP-7475, Section 5.4). 45 46
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If the evaporator feed has the 0.0007 g/L maximum Pu concentration, it entirely fills the 135 kL 1 volume of the evaporator vessel, and significantly exceeds the typical working volume, the 2 vessel would still only hold 94 g of Pu (RPP-7475, Section 6.1.6). This Pu mass is less than a 3 quarter of the 450 g subcritical limit discussed in Section 6.2 at which the requirements of 4 DOE O 420.1C become applicable. 5 6 The CSER provides the criticality evaluation for the 242-A Evaporator. The CSER and 7 Section 6.3 of RPP-13033 discuss the criticality safety concerns for the 242-A Evaporator and 8 the tank farms in more detail. Those analysis documents specifically address criticality safety 9 concerns with the uranium-235 and uranium-233 fissile nuclides that are also present in the 10 evaporator feed. The inventories of these fissile uranium nuclides are lesser concerns than the Pu 11 inventories in the evaporator feed, because of the accompanying presence of uranium-238 12 inventories that provide neutron absorption to ensure safety. The CSER also addresses the Pu 13 concentration increases caused by the evaporation process. The CSER concludes that operations 14 at the 242-A Evaporator will remain safely sub-critical for all normal and credible upset 15 conditions. 16 17 18 6.4 CRITICALITY CONTROLS 19 20 The CSER evaluates the operations at the 242-A Evaporator and identifies the criticality safety 21 controls necessary to ensuring safety. This section discusses the controls from the CSER. 22 23 24 6.4.1 Engineering Controls 25 26 The CSER covering 242-A Evaporator operations does not identify engineered controls to ensure 27 safety. 28 29 30 6.4.2 Administrative Controls 31 32 The CSER for the 242-A Evaporator provides a criticality safety control that limits the Pu 33 concentration in the feed to the 242-A Evaporator. The CSER does not identify the need for 34 criticality safety controls on any fire-fighting activities. 35 36 37 6.4.3 Application of Double-Contingency Principle 38 39 Applicability of the Double Contingency Principle within the CSP for the tank farms is 40 addressed in TFC-PLN-49 and in Section 6.4.3 of RPP-13033. 41 42 43 6.5 CRITICALITY SAFETY PROGRAM 44 45 Section 6.5 of RPP-13033 provides an overview of the CSP for the tank farms, including the 46 242-A Evaporator. Full documentation of the CSP for the tank farms is found in TFC-PLN-49. 47
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1 2 6.6 REFERENCES 3 4 ANSI/ANS-8.1-2014, Nuclear Criticality Safety in Operations with Fissionable Materials 5
Outside Reactors, American Nuclear Society, La Grange Park, Illinois. 6 7 DOE O 420.1C, Chg 1, 2015, Facility Safety, U.S. Department of Energy, Washington, D.C. 8 9 RPP-7475, Criticality Safety Evaluation Report for Hanford Tank Farms Facilities, as amended, 10
Washington River Protection Solutions LLC, Richland, Washington. 11 12 RPP-13033, Tank Farms Documented Safety Analysis, as amended, Washington River Protection 13
Solutions LLC, Richland, Washington. 14 15 TFC-PLN-49, Criticality Safety Program, as amended, Washington River Protection Solutions 16
LIST OF TERMS 1 2 3 DOE U.S. Department of Energy 4 5
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10.0 INITIAL TESTING, IN-SERVICE SURVEILLANCE, 1 AND MAINTENANCE 2
3 4 10.1 INTRODUCTION 5 6 This chapter provides the facility-specific safety-related details of the initial testing, in-service 7 surveillance, and maintenance program for the 242-A Evaporator specified by U.S. Department 8 of Energy (DOE)-STD-3009-94, Preparation Guide for U.S. Department of Energy Nonreactor 9 Nuclear Facility Documented Safety Analyses, Chapter 10.0. A description of the initial testing, 10 in-service surveillance, and maintenance program implemented by the Tank Operations 11 Contractor is provided in RPP-13033, Tank Farms Documented Safety Analysis, Chapter 10.0. 12 13 14 10.2 REQUIREMENTS 15 16 The initial testing program is established under RPP-PLAN-39433, Procurement, Construction, 17 and Acceptance Test Program Plan and RPP-PLAN-39434, Construction and Acceptance Test 18 Program. The Testing Program is implemented through TFC-PLN-26, Test Program Plan. 19 20 The Maintenance Management Program is established under DOE O 433.1B, Maintenance 21 Management Program for DOE Nuclear Facilities. The Maintenance Program implementation 22 is further described in TFC-PLN-29, Nuclear Maintenance Management Program. 23 24 The initial testing, in-service surveillance, and maintenance programs are described in 25 RPP-13033, Sections 10.3 through 10.5. 26 27 28 10.3 REFERENCES 29 30 DOE O 433.1B, 2010, Maintenance Management Program for DOE Nuclear Facilities, 31
U.S. Department of Energy, Washington, D.C. 32 33 DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor 34
Nuclear Facility Documented Safety Analyses, Change Notice No. 3, U.S. Department of 35 Energy, Washington, D.C. 36
37 RPP-13033, Tank Farms Documented Safety Analysis, as amended, Washington River Protection 38
Solutions LLC, Richland, Washington. 39 40 RPP-PLAN-39433, Procurement, Construction, and Acceptance Test Program Plan, 41
as amended, Washington River Protection Solutions LLC, Richland, Washington. 42 43 RPP-PLAN-39434, Construction and Acceptance Test Program, as amended, Washington River 44
11.0 OPERATIONAL SAFETY 1 2 3 11.1 INTRODUCTION 4 5 This chapter provides the facility-specific safety-related details of the operational safety program 6 specified by DOE-STD-3009-94, Preparation Guide for U.S. Department of Energy Nonreactor 7 Nuclear Facility Documented Safety Analyses, Chapter 11.0. A description of the operational 8 safety program implemented by the Tank Operations Contractor is provided in Chapter 11.0 9 RPP-13033, Tank Farms Documented Safety Analysis, Chapter 11.0. This chapter provides 10 242-A Evaporator facility-specific information so that this chapter, in combination with 11 Chapter 11.0 of RPP-13033, meets the requirements of DOE-STD-3009-94. 12 13 14 11.2 REQUIREMENTS 15 16 The requirements for operational safety are described in RPP-13033, Section 11.2. No facility-17 specific or unique aspects beyond the requirements presented in RPP-13033 have been 18 identified. 19 20 21 11.3 CONDUCT OF OPERATIONS 22 23 The conduct of operations is described in RPP-13033, Section 11.3. 24 25 26 11.4 FIRE PROTECTION 27 28 Fire protection is discussed in RPP-13033, Section 11.4 with the following additional 29 information. 30 31 Fire hazards at the 242-A Evaporator are identified in HNF-SD-WM-FHA-024, Fire Hazards 32 Analysis for the Evaporator Facility (242-A). Fire hazards that could result in the uncontrolled 33 release of radioactive and other hazardous materials are identified and evaluated in Chapter 3.0. 34 Fire protection systems are described in Section 2.7.1, and fire protection alarms, lights, and 35 signs are described in Section 2.7.3. 36 37 38
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11.5 REFERENCES 1 2 DOE-STD-3009-94, 2006, Preparation Guide for U.S. Department of Energy Nonreactor 3
Nuclear Facility Documented Safety Analyses, Change Notice No. 3, U.S. Department of 4 Energy, Washington, D.C. 5
6 HNF-SD-WM-FHA-024, 2017, Fire Hazards Analysis for the Evaporator Facility (242-A), 7
Rev. 8C, Washington River Protection Solutions LLC, Richland, Washington. 8 9 RPP-13033, Tank Farms Documented Safety Analysis, as amended, Washington River Protection 10
Solutions LLC, Richland, Washington. 11
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CHAPTER 12.0
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2
3
PROCEDURES AND TRAINING 4 5
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