Chemistry, Low Level Waste and Radiation Management August 2016 ISSUE STATEMENT Guidelines for water chemistry control and diagnosis spe- cific to advanced light water reactor operation do not cur- rently exist. Further, water chemistry control guidance for the current fleet does not address hot functional testing and initial plant start-up. Advanced plant designs have recently completed or are currently undergoing design certification by the U.S. Nuclear Regulatory Commission, and some designs are being constructed and operated in Europe and Asia. General assumptions were made on typical water chemistry environments during the design phase for the plants. ese assumptions were largely based on industry practices at the time of the plant designs, including previous versions of the applicable EPRI guidelines. EPRI’s technical assessments of the Design Control Documents (DCDs), and Combined Construction and Operating License Applica- tions (COLA) have identified differences between these doc- uments and the EPRI Water Chemistry Guidelines. Many of these differences are due to improvements in industry prac- tices since the time the plants were designed. However, oth- ers are due to fundamental differences in plant design. Rec- onciliation of these differences and closure of associated knowledge gaps is required for the PWR designs prior to June 2015 to support the planned 2017 start-up of the AP1000TM in the U.S., with the BWR designs to follow shortly thereafter. e result of this EPRI effort will be industry-consensus water chemistry control guidance for advanced plant designs that is consistent with the guidance available for the current fleet. is effort specifically addresses the AP1000TM, US-EPRTM, APR1400, US-APWR, ESBWR and ABWR designs. DRIVERS Asset Management New nuclear power plants are designed to operate differently and will be constructed using some different materials than those used in currently operating nuclear power plants. Water chemistry practices and technologies need to be eval- uated to ensure they adequately protect and do not nega- tively impact materials integrity and equipment reliability of the new plants. Hot functional, start-up, and early operations water chemis- try can impact materials and components throughout the life of the plant. In some cases, the new materials may be more resistant to corrosion than currently used materials, and certain water chemistry control and diagnostic relief may be possible. In other cases, the design of the new plant may make monitoring and maintaining the proper water chemistry more challenging. Fuel Performance New nuclear power plants are designed with higher duty cores than the industry typically has experienced. Water chemistry practices and technologies, such as zinc injection, coolant hydrogen controls and noble metal chemical addi- tion, need to be evaluated to ensure that they adequately protect and do not negatively impact fuel cladding integrity and the performance of core designs with these higher duties. Radiation Field Reduction Water chemistry practices and technologies must be evalu- ated to ensure activated corrosion product generation and transport (i.e., source term) is minimized in the new plants. Practices that can decrease the generation of corrosion prod- ucts from startup, such as chemical passivation, need to be considered during lay-up, hot-functional testing, and startup procedure formulation. Consideration of these processes from the beginning can have a lasting effect on reducing radiation fields, improving the industry’s ability to meet ever decreasing individual and total dose regulations and goals. Industry Initiatives Per NEI 97-06 Steam Generator Program Guidelines and NEI 03-08 Guideline for the Management of Materials Issues, U.S. nuclear plants must implement the EPRI Water Chem- istry Guidelines. e Water Chemistry Guidelines provide water chemistry control and diagnostic parameters to assure materials and fuel-cladding integrity, minimize radiation fields affecting personnel dose, optimize major component operation for long term reliability, and ensure environmen- tally sound effluent discharges. e existing guidelines have been optimized for currently operating plants. New nuclear power plants will be expected to operate to the EPRI Water Chemistry Guidelines as modified for their certified design. IN USE: WATER CHEMISTRY GUIDELINES FOR ADVANCED LIGHT WATER REACTORS
Transcript
Chemistry, Low Level Waste and Radiation Management August 2016
ISSUE STATEMENT
Guidelines for water chemistry control and diagnosis spe-cific to advanced light water reactor operation do not cur-rently exist. Further, water chemistry control guidance for the current fleet does not address hot functional testing and initial plant start-up. Advanced plant designs have recently completed or are currently undergoing design certification by the U.S. Nuclear Regulatory Commission, and some designs are being constructed and operated in Europe and Asia. General assumptions were made on typical water chemistry environments during the design phase for the plants. These assumptions were largely based on industry practices at the time of the plant designs, including previous versions of the applicable EPRI guidelines. EPRI’s technical assessments of the Design Control Documents (DCDs), and Combined Construction and Operating License Applica-tions (COLA) have identified differences between these doc-uments and the EPRI Water Chemistry Guidelines. Many of these differences are due to improvements in industry prac-tices since the time the plants were designed. However, oth-ers are due to fundamental differences in plant design. Rec-onciliation of these differences and closure of associated knowledge gaps is required for the PWR designs prior to June 2015 to support the planned 2017 start-up of the AP1000TM in the U.S., with the BWR designs to follow shortly thereafter. The result of this EPRI effort will be industry-consensus water chemistry control guidance for advanced plant designs that is consistent with the guidance available for the current fleet. This effort specifically addresses the AP1000TM, US-EPRTM, APR1400, US-APWR, ESBWR and ABWR designs.
DRIVERS
Asset Management
New nuclear power plants are designed to operate differently and will be constructed using some different materials than those used in currently operating nuclear power plants. Water chemistry practices and technologies need to be eval-uated to ensure they adequately protect and do not nega-tively impact materials integrity and equipment reliability of the new plants.
Hot functional, start-up, and early operations water chemis-try can impact materials and components throughout the life of the plant. In some cases, the new materials may be more resistant to corrosion than currently used materials, and certain water chemistry control and diagnostic relief may be possible. In other cases, the design of the new plant may make monitoring and maintaining the proper water chemistry more challenging.
Fuel PerformanceNew nuclear power plants are designed with higher duty cores than the industry typically has experienced. Water chemistry practices and technologies, such as zinc injection, coolant hydrogen controls and noble metal chemical addi-tion, need to be evaluated to ensure that they adequately protect and do not negatively impact fuel cladding integrity and the performance of core designs with these higher duties.
Radiation Field ReductionWater chemistry practices and technologies must be evalu-ated to ensure activated corrosion product generation and transport (i.e., source term) is minimized in the new plants. Practices that can decrease the generation of corrosion prod-ucts from startup, such as chemical passivation, need to be considered during lay-up, hot-functional testing, and startup procedure formulation. Consideration of these processes from the beginning can have a lasting effect on reducing radiation fields, improving the industry’s ability to meet ever decreasing individual and total dose regulations and goals.
Industry InitiativesPer NEI 97-06 Steam Generator Program Guidelines and NEI 03-08 Guideline for the Management of Materials Issues, U.S. nuclear plants must implement the EPRI Water Chem-istry Guidelines. The Water Chemistry Guidelines provide water chemistry control and diagnostic parameters to assure materials and fuel-cladding integrity, minimize radiation fields affecting personnel dose, optimize major component operation for long term reliability, and ensure environmen-tally sound effluent discharges. The existing guidelines have been optimized for currently operating plants. New nuclear power plants will be expected to operate to the EPRI Water Chemistry Guidelines as modified for their certified design.
IN USE: WATER CHEMISTRY GUIDELINES FOR ADVANCED LIGHT WATER REACTORS
EPRI | Nuclear Sector Roadmaps August 2016
RESULTS IMPLEMENTATION
Utilities will develop and work with EPRI to implement plant-specific Strategic Water Chemistry Plans, based on the guidance provided in the EPRI Water Chemistry Guidelines revised to include applicability to advanced plant designs. This includes hot functional testing and start-up guidance, which is not part of the current EPRI Water Chemistry Guidelines. Utilities will need to train existing and new chemistry managers and technicians to implement Strategic Water Chemistry Programs for the new nuclear power plants. Nuclear steam supply system vendors will use these guidelines to support new plant development.
An important aspect for effective implementation will be to capture lessons learned and data related to hot functional testing, startup, and early operations from lead plants to sup-port industry wide application of these guidelines. This pro-cess will include the following:• Partnering with lead plants and associated vendors to
develop Strategic Water Chemistry Programs per the Water Chemistry Guidelines
• Collection and analysis of data and experiences from the lead plants
• Review and revision of guidelines
PROJECT PLAN
Understand Current Status of ALWR Design Impacts on Water Chemistry• Conduct gap analysis to identify differences between cur-
rent Water Chemistry Guidelines and intended chemistry related operations of the new nuclear power plants.
• Prioritize and categorize gaps and develop research and development plans to address and close gaps.
Adapt Water Chemistry Guidelines for Applicability to ALWRs • Work with new plant designers and fuel vendors to fully
understand the new plant systems and components and establish technical bases for water chemistry control and diagnostics.
• Understand the impacts and benefits of chemistry tech-nologies (i.e., zinc injection, hydrogen water chemistry) on new plant fuels and materials.
• Address gaps and develop guidance for the ALWRs, including guidance for hot functional testing, startup, and early operations.
• Adapt current EPRI Water Chemistry Guidelines for appli-cability to ALWRs.
Include ALWR Designs in the Revision Process for EPRI Water Chemistry Guidelines• Collect and analyze data and experiences from hot func-
tional testing, startup, and early operations with respect to management of dissolved gases, operations of cleanup systems, buildup of oxides, corrosion, establishment of steady state chemistry conditions, generation of radiation source terms, etc. Review and revise Guidelines as neces-sary.
RISKS
External StakeholderData and information required to develop technical bases for water chemistry guidance for ALWRs is not available or provided. To mitigate this risk, EPRI will work closely with the NSSS vendors, independent industry experts and utili-ties to maximize data availability. The technical bases for existing water chemistry control guidance will be evaluated for applicability to the advanced plant designs and will serve as the default basis in the event design-specific information is unavailable.
Technology Implementation ConstraintAvailable timeframe is not sufficient to adequately address technical gaps. Closure of the identified technical gaps has been prioritized to ensure all gaps applicable to multiple plant designs and critical technical gaps for specific plant designs are addressed first. Closure of remaining technical gaps will be completed as soon as practicable. Operation of some advanced plant designs outside of the U.S. will com-mence prior to completion of the Guidelines. Operational experience from these lead plants will be incorporated in the guidance in parallel with Guideline development, and early draft guidance will be provided to these lead plants for com-ment and use, as applicable.
Chemistry, Low Level Waste and Radiation Management August 2016
RECORD OF REVISION
This record of revision will provide a high level summary of the major changes in the document and identify the Road-map Owner.
revision description of change
0 Original Issue: August 2011 Roadmap Owner: Karen Kim
1 Revision Issued: August 2012 Roadmap Owner: Rick Reid
Changes: Revised flowchart to reflect funding for 2012 scope. Revised Issue Statement to better reflect the division of responsibility between EPRI and NSSS vendors for development of water chemistry guidance for advanced plant designs. Revised Risk section to include discussion on mitigative actions for the identified program risks.
2 Revision Issued: August 2013 Roadmap Owner: Rick Reid
Changes: Revised Results Implementation and Project Plan to indicate chemistry guidance for new plant designs will be incorporated into existing EPRI Guidelines rather than as stand-alone documents. Flow chart revised accordingly.
3 Revision Issued: August 2014 Roadmap Owner: Rick Reid
Changes: 1) Revised to clarify applicability to AP1000TM, US-EPR, APR1400, US-APWR, ESBWR and ABWR designs; 2) revised flow chart to reflect current schedule for startup of advanced plant designs.
4 Revision Issued: August 2016 Roadmap Owner: Dan Wells
Changes: Revised flow chart to reflect current schedule for startup of advanced plant designs and project tasks.
