t REG UNITED STATES NUCLEAR REGULATORY COMMISSION REGION II 101 MARIETTA STREET, N.W., SUITE 2900 ATLANTA, GEORGIA 30323-0199 Report Nos.: 50-390/93-87 and 50-391/93-87 Licensee: Tennessee Valley Authority 6N 38A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Docket Nos.: 50-390 and 50-391 License Nos.: CPPR-91 and CPPR-92 Facility Name: Watts Bar 1 and 2 Inspection Conducted: December 1 through December 31, 1993 Inspectors: Consultants: Approved by: G. A. Walton, 5'iior Resident Inspector 2DI Construction R. M. Compton, Nuclear Power Consultants, Inc. W. S. Marini, Pegasus, Inc. (paragraphs 2.a, b, D. 0. Myers, Beckman and Associates (paragraphs P Fredrickson, Section Chief Division of Reactor Projects ate Signed (paragraph 2.e) c, d) 2.1, g, h, i, ate Signed SUMMARY Scope: This routine resident inspection was conducted by NRC consultants for the review of actions on previous inspection findings. Results: This inspection for the closure of open items found that the licensee had adequately resolved the issues for most of the items reviewed. The quality and detail of the packages provided by the licensee for each item were adequate for inspector follow-up. 944028o0oo3 94o012" 0PDR OCK 0500,0 PDR
Docket Nos.: 50-390 and 50-391 License Nos.: CPPR-91 and CPPR-92
Facility Name: Watts Bar 1 and 2
Inspection Conducted: December 1 through December 31, 1993
Inspectors:
Consultants:
Approved by:
G. A. Walton, 5'iior Resident Inspector 2DIConstruction
R. M. Compton, Nuclear Power Consultants, Inc.W. S. Marini, Pegasus, Inc. (paragraphs 2.a, b,D. 0. Myers, Beckman and Associates (paragraphs
P Fredrickson, Section ChiefDivision of Reactor Projects
ate Signed
(paragraph 2.e)c, d)2.1, g, h, i,
ate Signed
SUMMARY
Scope:
This routine resident inspection was conducted by NRC consultants for thereview of actions on previous inspection findings.
Results:
This inspection for the closure of open items found that the licensee hadadequately resolved the issues for most of the items reviewed. The qualityand detail of the packages provided by the licensee for each item wereadequate for inspector follow-up.
944028o0oo3 94o012"0PDR OCK 0500,0PDR
REPORT DETAILS
1. Persons Contacted
Licensee Employees
M. Alexander, Concerns Resolution StaffK. Boyd, Site Licensing Program AdministratorJ. Christensen, Construction Quality Assurance Manager
*R. Johnson, Acting Engineering Manager*N. Kazanas, Vice President Completion AssuranceD. Koehl, Technical Support ManagerL. Maillet, Site Support Manager
*T. Porter, Manager of Special Projects*J. Scalice, Vice President Site OperationsS. Tanner, Special Projects Manager
Other licensee employees contacted included engineers, technicians,
nuclear power supervisors, and construction supervisors.
NRC Personnel:
*K. Ivey, Resident Inspector, WBN
*Attended exit interview
Acronyms and initialisms used throughout this report are listed in thelast paragraph.
2. Actions on Previous Inspection Findings (92700, 92701, 92702)
a. (Closed) CDR 50-390/83-49, Lugs Welded to Spiral Welded Pipe
This 10 CFR 50.55(e) report involved lugs that were weldeddirectly to spiral welded HVAC ducts and supports. The identifieddeficiency was that during a seismic event, the spiral weldedduct, which has a wall thickness of .134 inches, could become
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overstressed and tear thus failing to maintain its pressureboundary integrity.
As discussed in IR 50-390, 391/91-26, the licensee's actions toresolve this deficiency had previously been reviewed with thefollowing two issues remaining to be addressed.
Although hoop rings had been installed in accordance withECNs 4331 and 4567, the lugs were still welded to both theduct and the supports. It was not clear whether the intentof the revised design was to remove the lug welds or leavethem in place.
Drawing details required the hoop rings to be notched toavoid interference with the spiral weld as it passed thesupport. Instead, the spiral weld had been ground flushwith the pipe wall.
As part of the HVAC Duct and Duct Support CAP, boundingcalculations were performed for typical types of the supports inquestion, assuming attachments to the ducts utilizing the originalwelded lugs only. As shown in calculations WCG-1-1246, Revision1, WCG-1-444, WCG-1-1240, Revision 2, WCG-1-445, 50098.01-C-006,WCG-1-1230, Revision 1, WCG-1-446,.WCG-1-448, and WCG-1-664,Revision 1, local stresses in the ducts were found to be withinthe allowable limits. In addition, it was found that the hooprings, although not essential to qualify the installation, mayremain in place as they will further reduce the local stresses.To address the issue of the ground spiral Welds, calculationWCG-1-1247 was performed which determined that, as only weldreinforcement had been removed, the installations were acceptableas is.
The inspector reviewed the methodology and assumptions utilized inthe above calculations and found that they were adequate toresolve the two remaining issues. In addition, as stated inIR 50-390, 391/91-26, the inspector had previously verified thatthe welds were ground flush with the pipe wall. Therefore, thelicensee's statement that only weld reinforcement was removed wasfound to be accurate. This item is closed.
b. (Closed) BU 50-390/87-01, Erosion/Corrosion Induced Pipe WallThinning
This BU was issued to request licensees to submit informationconcerning their programs for monitoring the thickness of pipewalls in high-energy, single-phase and two-phase carbon steelpiping systems. In August 1989, NUREG/CR-5287 was published toconfirm that no further plant-specific action by licensees inresponse to BU 87-01 was required, and that actions regardingimplementation of erosion/corrosion monitoring programs would becovered by GL 89-08. In accordance with NRR memoranda dated
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July 3, 1989, August 21, 1989, and April 20, 1990, review andclosure of licensee actions associated with GL 89-08 will beaccomplished under NRC TACs 73561 and 73562. Therefore, this itemis closed.
c. (Open) CDR 50-390/91-09, Limitorque SMB-O0 Torque Switch Roll PinFailures
This 10 CFR 50.55(e) report was issued as a result of a 10 CFR 21report from Limitorque Corporation involving potential failures ofroll pins in Type SMB-00 torque switches. Review by the licenseedetermined that there are 70 safety-related MOVs required forUnit 1 operation that could have the potentially defective rollpins installed. These MOVs are listed by system in SCARWBSCA9102.13, Revision 1. In a letter to the NRC (RIMST04921019998) dated October 19, 1992, the licensee committed toinspect the suspect MOVs and replace the affected torque switchesprior to system completion and startup testing.
To determine whether switch replacement was being accomplishedprior to system completion, the inspector selected three systems(62, CVCS; 70, CCS; and 74, RHR) containing 22 MOVs required forUnit I operation. From a review of plant maintenance recordsgenerated in accordance with procedure PMI-1380V, RoutineInspection and Maintenance of Limitorque Motor Actuators,.Revision 9, the inspector determined that required switchreplacements had been accomplished prior to completion of thesesystems. No deficiencies were identified.
This item will remain open pending the completion of switch
replacement for the remaining 48 MOVs.
d. (Closed) IFI 50-390/93-48-01, Pressurizer Heater Cables
This item involved a discrepancy between the FSAR and theapplication of Raychem splices for the pressurizer heater cables.Originally, FSAR Chapter 8.3.1.2.3 classified these cables asClass 1E (safety-related). However, the installed cables are notrated for a LOCA environment, and splices were installed in aconfiguration that was unqualified for conditions present duringand/or subsequent to an accident.
To -resolve the identified discrepancy, the licensee prepared anamendment to the above FSAR chapter to re-classify the pressurizerheater cables as non-IE (nonsafety-related). This amendment iscontained in FSAR Change Package No. 0977, with justificationprovided by Westinghouse position letter WAT-D-5029, datedAugust 4, 1982. This item is closed.
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e. (Closed) IFI 50-390/93-202-03, Component Cooling System Surge TankOverpressure Protection
This item was opened as a result of the 1993 IDI of mechanicalsystem aspects of the ERCW system and CCS. The item related to aconcern regarding the potential for overpressurizatlon of the CCSsurge tank if the vent line was closed during emergency makeupoperations. Previous NRC inspections of the licensee's actionswith regard to this item, including revision of the CCS systemdescription, were documented in IR 50-390, 391/93-65.
During this inspection period, the inspector reviewed Revision 25to procedure SOI-70.01, Component Cooling Water, issued onNovember 24, 1993. The inspector confirmed that positive controlswere included to assure the CCS surge tank vent valves are openprior to use of the tanks for emergency makeup. This item isclosed.
f. (Closed) CDR 50-390, 391/91-40, Inadequate Selective BreakerCoordination
This issue involved the selective tripping function of importantfeeder breakers supplied from the 480V shutdown boards. InIR 50-390, 391/93-36, the inspectors stated that this issue wouldremain open until problems associated with the implementedcorrective actions were adequately addressed.
WBN had learned about the problem through the review of anincident investigation report issued by SQN. Corrective actiondocument SCAR WBNSCA910278 was generated, and a 10 CFR 50.55(e)report was issued on December 12, 1991. The licensee issuedDCN M-18152-A to modify the amptectors to eliminate themiscoordination problem. The DCN was performed after consultingthe vendor.
The inspector reviewed DCN M-18152-A and noted severaldiscrepancies, such as an apparent failure to modify the sparebreakers located in the warehouse and ambiguous documentation ofwork performed. In conjunction with the NRC inspection effortsfor the CDR closure, the licensee had issued SCAR WBNSCA93043 onMarch 31, 1993, which stated that during a drawing review andcomponent walkdown by startup personnel several of the breakers onthe shutdown boards had not had the amptector discriminatorcircuits jumpered as intended by DCN M-18152-A, and alsoidentified problems similar to those independently discovered bythe NRC.
On May 7, 1993, the NRC issued VIO 50-390/93-23-01, InadequateCorrective Action for a Breaker Coordination Problem, to documentthe failure to correct a condition adverse to quality (CDR 50-390,391/91-40). As a result of the failure to implement adequatecorrective actions, the licensee issued CDR 50-390, 391/93-01 on
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June 17, 1993. This CDR was closed in IR 50-390, 391/93-51, bystating that the corrective actions were addressed by the responseto the VIO.
During this inspection period, the inspector reviewed thelicensee's June 7, 1993, response to VIO 50-390/93-23-01 anddetermined that the corrective actions for CDR 50-390, 391/91-40were fully within the scope of the conditions addressed by theVIO. In addition, the inspector determined that the VIO providedthe necessary cross references to ensure that all correctiveactions had been properly addressed. The adequacy of correctiveactions taken for this CDR will be reviewed in conjunction withclosure of VIO 50-390/93-23-01. This item is closed.
g. (Closed) IFI 50-390/86-08-01, Discrepancy Between Most HeavilyLoaded, Worst Condition Shutdown Board 1B-B or 2B-B
This item was identified during a review of test proceduresTVA-73B, Additional Diesel Generator Sequenced Loading, andTVA-73C, Additional Diesel Generator Qualification Test, duringpre-operational testing in 1986. The inspector noted thatprocedure TVA-73B designated the 2B-B DG as the most heavilyloaded, worst condition DG when the FSAR documented the lB-B asthe worst case loading. In the IR, the inspector stated that thelicensee would evaluate the issue and change either the FSAR orthe test procedure.
The licensee had provided a calculation, WBN-EEB-MS-TI03-0012,Diesel Generator Loading Analysis, Revision 13, which indicatedthat DG 2B-B was the most heavily loaded DG; however, inIR 50-390, 391/93-01, the inspector documented that Section 8.3 ofthe FSAR had not been changed to reflect the results of theengineering calculation for the worst case loading on a DG. Theinspector also documented that the IFI would remain open until theFSAR discrepancies on DG loading were properly addressed inChapter 8 of the FSAR.
During this inspection period, the inspector reviewed thelicensee-initiated FSAR change request and found that it correctedSection 8.3 of the FSAR to indicate that DG 2B-B-represented theworst case loading for site DGs. This change made the sectiondescription consistent with calculations and other sections of theFSAR. This item is closed.
h. (Closed) URI 50-390, 391/92-29-05, Applicability of Unit 2 MissingVanes to Unit 1
This issue involved a concern on the resolution of a Unit 2 NCR7029 which identified that turning vanes had not been installed inHVAC duct work as specified by drawing 47W910-1, Note IA. Bothlicensee Engineering and QC had failed to recognize the absence of
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the turning vanes. The NRC expressed concerns about the statusand processing of the NCR as-follows:
accuracy of the determination that the NCR wasnonsignificant;
accuracy of the classification as "non-applicable" toUnit 1; and
deferral of the root cause and extent of applicabilityreviews.
Turning vanes have the purpose of preventing turbulence andconsequent high loss on total pressure where 90 degree turns arenecessary in rectangular ducts by smoothly turning the air.Although large radius turns may be used for the same purpose, morespace would be required. Missing vanes may result in decreasedair flow and changes in loads on axial supports and duct seamsfrom increased internal pressures.
During this inspection period, the inspector reviewed licenseeengineering calculations and corrective action documents to verifythe adequacy of the licensee's actions. The issue of thenon-significance of the NCR was addressed by the licensee usingthe criteria in procedure AI-7.11, Evaluation for Unit 2 HoldStatus. The licensee provided additional evidence in calculationWBNOSG4-136, Steady State DBE Temperatures for the AuxiliaryBuilding, Revision 2, that the flow rates in Unit I duct work metdesign requirements. In addition, analysis of turning vane axialloads had been addressed in the Sargent and Lundy VSR conducted atWBN. One item in finding VSR 004 identified that WBN failed toconsider the effects of dynamic loads imparted by turning vanes inseismic analysis of duct work supports. The issue was documentedon CAQR WBP880543 and was resolved by the issuance of calculationWCG-1-520, HVAC Turning Vane Evaluations, and a revision(Revision 7) to design criteria WB-DC-40-30.8, SeismicallyQualifying Round and Rectangular Duct. This calculationdocumented that duct work was adequately supported in both Unit 1and Unit 2 with or without turning vanes. Based on thecalculations, the inspector considered that the determination ofnon-significance met program requirements.
The remaining two NRC concerns questioned the licensee's effortsto verify that the omission of turning vanes did not causesignificant detrimental effects in Unit 1 ventilation systems.The licensee stated that the results of an additional informalwalkthrough of Unit 1 indicated that rivet patterns on elbowsprovided evidence that the turning vanes were installed. However,no formal inspections were planned. In addition, the ventilationsystem met its design requirements regardless of whether the vaneswere installed or not, as evidenced through testing andcalculations as reported by the licensee.,
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The complete retesting of the safety-related ventilation andcorrection of any deficiencies is part of the pre-operationaltesting program that is required prior to Unit I licensing. Anydefects in system performance will be diagnosed and corrected aspart of that program. This item is closed.
i. (Closed) IFI 50-390, 391/93-59-08, Verify Implementation of RIMSCross Reference Document for Westinghouse Valves
This issue resulted from the NRC records review program andaddressed the documentation for Westinghouse valves that had 24character serial numbers and had been recorded in severaldifferent formats on different plant records during theconstruction years. The different formats caused confusion whentracking records on important valves.
A licensee review indicated that the affected Westinghouse valvesdid have a common type of number (NBN) that had been recordedproperly in all cases. The licensee developed a cross referenceof the valve serial numbers and applicable NBNs (NBNs wereretrievable through the RIMS system) to enhance the retrievabilityof permanent plant records (such as the ASME required NPV-1 andNP-5 Forms). The cross reference listed four identifying numbers:the NBN; the serial number as listed on the NPV-1 form; the serialnumber as listed on the NP-5 form; and the TVA identifier. Thecross reference was transmitted to RIMS where it was designed tobe referenced when either the NP-5 or NPV-1 numbers were calledfor Westinghouse valves.
The inspector reviewed the cross reference and verified that whenRIMS was accessed with a serial number for a valve, the crossreference was displayed and enabled the user to realize otheridentified numbers had been used in the past. This item isclosed.
(Closed) 10 CFR Part 21, 50-390, 391/84-02, Valve Closure Springon Terry Turbine Trip and Throttle Valve Does Not Ensure ClosureUnder Certain Operating Conditions
Terry Corporation notified TVA by letter dated February 3, 1984,that during testing at a power plant, a 4-inch Gimpel trip andthrottle valve did not fully close under certain conditions. Theconditions noted were high inlet pressure and low steam flow.This issue was tracked by the NRC as a potential Part 21 and wasreviewed and left open in two inspection reports: IR 50-390,391/90-17, when a request of the status of the trip and throttlevalve was made and the licensee determined that no evidence ofalterations to the valve could be found; and IR 50-390,:391/93-72,when work was ongoing to replace a closure spring.
The licensee had updated vendor manual WBN-VTM-DR-0240,Dresser-Rand (formerly Ingersoll-Rand) Turbine Driven Auxiliary
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Feedwater Pumps, Revision 4 (RIMS T28 920819 841), to add a letterdescribing the modified closing springs for the Gimpel trip andthrottle valve used in the pump assembly and the proposed retestrequirements.
NRC inspectors witnessed valve modification work and reviewed thework document (WO 93-11375-00). IR 50-390, 391/93-74 documentsproblems associated with the initial WO. The WO was subsequentlyrevised, and the licensee completed the actions to install andthen test the new valve spring on the Gimpel valve (1-FCV-1-51-S).The inspector reviewed the completed work and retest documents andidentified no deficiencies. This item is closed.
k. (Open) VIO 50-390/93-23-01, Inadequate Corrective Action for aBreaker Coordination Problem
This issue involved the licensee's failure to implement correctiveactions for defects associated with the selective trippingfunction of important 480V shutdown board feeder breakers. Thedefective component was initially reported to the NRC as CDR50-390/91-40. In IR 50-390, 391/93-36, inspectors documented thatCDR 50-390/91-40 would remain open until problems associated withthe corrective actions were addressed. CDR 50-390/91-40 wasclosed in paragraph 2.f of this report because the correctiveactions for the condition are fully within the scope of theconditions that were addressed by VIO 50-390/93-23-01.
Selective tripping is the engineering feature that enableselectrical circuit breakers to trip as close as possible to theequipment that is making abnormally high current demands on itsnormal power supply. This attribute enables circuit breakersupstream of the faulted circuit to continue to supply other loadsinstead of tripping when any of the dozens of components itsupplies through other circuits experiences a problem. Selectivetripping is achieved through the use of a solid state trip unit,referred to as an amptector, and is supplied by the vendor for usein each Westinghouse type DS power circuit breaker. The licenseedetermined through testing of trip devices that a defect existedthat would cause an instantaneous rather than a delayed trip ofsome circuit breakers. The corrective actions specified were toperform a modification which would install a jumper that wouldcorrect the condition in all affected breakers.
The licensee responded to the VIO in a letter dated June 7, 1993,and stated that the reason for the VIO was ineffectivecoordination of DCNs and associated WPs which permitted breakersto be transferred at the same time the breakers were beingverified for jumper installation. The corrective actionsconsisted of a field walkdown of affected breakers to assure thatthe required modification had been performed, memoranda wereissued to design engineers and DCN closure engineers to reinforcetheir responsibility to account for ongoing modifications, and the
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importance of checking the impact of predecessor DCNs during theclosure process. In addition, a review of the implementation ofDCNs containing multiple WPs would be performed to determine ifsimilar problems existed in other DCNs.
On October 29, 1993, the licensee initiated SCAR WBNSCA930192 toidentify that the defective condition affecting the circuitbreakers listed in CDR 50-390, 391/91-40 also applied to anothersize of similar circuit breakers. CDR 50-390, 391/91-40 appliedto Westinghouse breaker type DS-206. The same amptector tripdevice was used in Westinghouse type DS-416 breakers which werereported to be used in safety-related applications at WBN. Theeffects of the defective tripping devices had not been evaluatedfor the DS-416 breakers.
The inspector reviewed SCAR WBNSCA930192 and the VIO response anddetermined that actions to prevent recurrence of amptector mis-application may not have been effective. This VIO will remainopen pending verification of the corrective actions and evaluationof the SCAR.
3. Exit Interview
The inspection scope and findings were summarized on December 30, 1993,with those persons indicated in paragraph 1. The inspectors describedthe areas inspected and discussed in detail the inspection results.Dissenting comments were not received from the licensee. Proprietaryinformation is not contained in this report.
Item Number
390/83-49
390/84-02391/84-02
390/86-08-01
390/87-01
Status
Closed
Closed
Closed
Closed
Descriotion and Reference
CDR - Lugs Welded to SpiralWelded Pipe (paragraph 2.a)
P21 - Valve Closure Spring onTerry Turbine Trip andThrottle Valve Does Not EnsureClosure Under CertainOperating Conditions(paragraph 2.j)
Administrative InstructionAmerican Society of Mechanical EngineersBulletinCorrective Action PlanCondition Adverse to Quality ReportComponent Cooling SystemConstruction Deficiency ReportCode of Federal RegulationsChemical and Volume Control SystemDesign Basis EventDesign Change NoticeDiesel GeneratorEngineering Change NoticeEssential Raw Cooling WaterFinal Safety Analysis ReportGeneric LetterHeating, Ventilation, and Air ConditioningIntegrated Design InspectionInspection Follow-up ItemInspection Report
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LOCA Loss of Coolant AccidentMOV Motor Operated ValveNBN National Board NumberNCR. Nonconformance ReportNRC Nuclear Regulatory CommissionNRR Nuclear Reactor RegulationNUREG/CR NUREG Contractor ReportPMI Plant Maintenance InstructionQC Quality ControlRHR Residual Heat RemovalRIMS Records Information Management SystemSCAR Significant Corrective Action ReportSOl System Operating InstructionSQN Sequoyah Nuclear PlantTAC Task Action CommitmentTVA Tennessee Valley AuthorityURI Unresolved ItemVIO ViolationVSR Vertical Slice ReviewWBN Watts Bar Nuclear PlantWO Work OrderWP Workplan
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