WALKDOWNS OF US NPPS operating US NPPs based on Lessons and - PowerPoint PPT Presentation

SMiRT 22 Special Session THE NTTF 2.3 SEISMIC on Seismic reevaluation of WALKDOWNS OF US NPPS operating US NPPs based on Lessons and Insights NRC Fukushima Task Force Topics 2.1 & 2.3 August 2013

PRESENTATION TOPICS ¡ Background and objective of the walkdowns ¡ Guidance document contents ¡ Key walkdown elements and approaches ¡ Outcomes and insights

NEAR TERM TASK FORCE (NTTF) 3

SEISMIC NTTF ACTIVITIES OVERVIEW Based on the 50.54(f) letter: Walkdowns to assure plants are meeting licensing basis and to look for potential seismic 11/2012 2.3 Walkdowns (+outages) issues. Reports due November 2012. Some equipment delayed until outages. Ongoing 9/2013 Hazard evaluation due in 18 months for NPPs Hazard (CEUS) within the CEUS SSC model area. 3 years for western US NPPs performing SSHAC level 3 evaluation 3/2015 studies. Plant-specific site response. (WUS) Risk results due 3-4 years after hazard. SMAs Risk only allowed for small exceedance levels. SPRAs 3 years 2.1 after hazard allowed for all exceedances, but required for evaluation large exceedances. Near term Regulatory After receiving the information from the SPRA Depends on and SMA analyses, the NRC will determine findings Actions appropriate regulatory actions. 10 year Rulemaking Rulemaking to require a reevaluation every 10 Long term 2.2 timeline years. update 4

NTTF ACTIVITIES ¡ 50.54(f) RFI Letter issued March 12, 2012 ¡ Enclosure 3 Seismic Walkdowns “T “The walkdown will verify current plant conf configur iguration with the ation with the curre current lice nt licensing nsing basis, v basis, verify the rify the ade adequacy of curre quacy of current nt stra st rategies, maintenance plans, and identify degr degraded, ded, nonconf nonconform orming, ing, or una or unana naly lyzed zed conditions.” conditions.” ¡ The R2.3 seismic walkdowns provide a level of confidence in plant capabilities as new seismic hazard and risk assessment is ongoing. 5

NTTF ACTIVITIES ¡ Steps outlined in Enclosure 3 “Seismic Walkdowns” o Gather information per the Staff Requirements Memorandum (SRM) for SECY-11-0124 o Develop methodology and acceptance criteria o Perform walkdowns o Address potential deficiencies o Verify adequate monitoring and procedures 6

EPRI GUIDANCE FOR SEISMIC WALKDOWNS ¡ EPRI Guidance 1025286, “Seismic Walkdown Guidance” ¡ Developed through close cooperation of EPRI and NRC experts ¡ Endorsed 5/31/12 ¡ Shouldn’t be used for any other purpose. Recommendation 2.1 reevaluations use: § EPRI 1025287 (SPRA) § NRC ISG JLD-ISG-2012-04 (SMA) § EPRI/NP-6041-SLR1 (SMA) 7

NTTF ACTIVITIES ¡ As per 50.54(f) letter, report should include o Plant hazard licensing basis Defines R2.3 o Walkdown process Objectives and o IPEEE vulnerabilities and actions taken to eliminate or reduce them o Walkdown results and key findings Reporting o Detailed description of actions taken for (incorporated into potential vulnerabilities o Planned or installed protection features guidance) o Impact of peer review 8

GUIDANCE CONTENTS ¡ Personnel (Ch 2) ¡ Developing the SWEL (Ch 3) ¡ Conducting walkdowns & walk-bys (Ch 4) ¡ Addressing potential issues (Ch 5) § Licensing basis reviews, CAP submittals ¡ IPEEE enhancements (Ch 7) ¡ Peer review (Ch 6) ¡ Reporting (Ch 8) 9

GUIDANCE APPENDICES A: Initializations and Acronyms B: Classes of Equipment C: Checklists D: Seismic Spatial Interaction E: Systems to Support Safety Functions F: Checklist for Peer Review of SSC Selection G: Definition of Terms H: Mapping to Documentation Requirements in 50.54(f) Letter 10

PROGRAM PERSONNEL (CH 2) ¡ All must have relevant experience/knowledge in their areas of participation § Specific attributes are listed in the guidance ¡ 6 Key personnel types § Equipment Selection Personnel § Plant Operations Personnel § General support and asked to sign the SWEL along with the equipment selection personnel § Seismic Walkdown Engineers § Required to attend a (2 day) EPRI or (5 day) SQUG training on the guidance § Licensing Basis Reviewers § IPEEE Reviewers § Peer Reviewers § Minimum of 2 for each element, with one acting as lead reviewer and performing review of all elements as described in guidance 11

DEVELOPING THE SWEL (CH 3) ¡ Seismic walkdown equipment list (SWEL) ¡ SWEL 1 (NPP) + SWEL 2 (SFP) = SWEL ¡ SWEL 1: Smart sampling of NPP equipment that covers the five safety functions § 4 safety functions + containment § New/Replacement equipment and IPEEE enhancements ¡ SWEL 2: Spent fuel pool § Sample from SC1 SPF equipment § ALL SSCs that can cause rapid drain down 12

DEVELOPING THE SWEL (CH 3) Figure 1-1 Limits Limits items to items to Exclusion Exclusion Broad what is Criteria what is Criteria Inclusion sampling important important Criteria Broad of Plant Inclusion sampling Criteria Figure 1-2 of Plant SWEL 1 SWEL 2 13

DEVELOPING THE SWEL (CH 3) Figure 1-1 SWEL 1 SWEL 2 Figure 1-2 SWEL 14

INCLUSION CRITERIA SWEL 1 (CH 3) ¡ Inclusion Criteria for Sampling (screen 4) § Variety of systems (examples in App E) § Major new or replacement equipment § Variety of types of equipment (list in App B) Inclusion § Variety of environments Criteria § Equipment enhanced due to IPEEE program ¡ Sampling a pragmatic approach to limited time to conduct the walkdowns 15

INCLUSION CRITERIA SWEL 2 (CH 3) ¡ Inclusion Criteria for Sampling ¡ Same as SWEL 1 but without IPEEE upgrades SWEL 2 also includes… 16

INCLUSION CRITERIA SWEL 2 (CH 3) ¡ ALL items of the SFP that could cause rapid drain-down, even if such items are not Seismic Category I ¡ Rapid drain down is draining to the top of fuel in 72 hours after accounting for sloshing and boil off. 17

WHAT ARE WALKDOWNS VERSUS WALK-BYS? (CH 4) ¡ Walkdowns are intensive visual inspection of a piece of equipment that is focused specifically on the equipment and its immediate area. ¡ Walkdowns look for anchorage conditions, potential interaction problems, other conditions (e.g., material degradation, heavy items mounted to cabinets, loose attachments) ¡ These are “vulnerability walkdowns”. Some plants may have additional walkdowns as part of R2.1. 18

WHAT ARE WALKDOWNS VERSUS WALK-BYS? (CH 4) ¡ Walk-bys are… § visual examinations of an area that consider the overall condition of the area. § conducted for each of the areas in which the SWEL item is located. § focused on obvious degradation, possible interactions and initiators (fire, flood, etc), and housekeeping. § efficient ways to review a larger plant area as they are conducted when the SWEs are already in the area. 19

ANCHORAGE VERIFICATIONS (CH 4) ¡ 50% of the anchorages (for items that have anchorages) must be checked against the licensing basis. ¡ Several types of information could have been used. § Design drawings § Seismic qualification reports of analyses or shake table tests § IPEEE or USI A-46 program documentation 20

WALKDOWN CHECKLIST (APP C) Checklists are set up so that all the answers indicating “no problems” are “yes” 21

ADDRESSING POTENTIAL ISSUES (CH 5) ¡ Potential issues identified in the Figure 1-3 walkdowns go to licensing basis evaluations ¡ If not easily dispositioned, item is added to the CAP ¡ All open items at time of reporting go into the CAP 22

WHY REVISIT IPEEE VULNERABILITIES? (CH 7) ¡ The IPEEE program did not require licensees to report when the changes identified in the IPEEE program had been completed. ¡ NRC staff needs this information for current activities. It is requested in the 50.54(f) letter ¡ NRC asked to also verify the current status of the changes, if information is readily available. ¡ A range of actions could have been taken, to eliminate or reduce seismic vulnerabilities. So, methods for verifying completion will vary. 23

PEER REVIEW (CH 6) ¡ Peer review should start early and is conducted throughout the project ¡ A minimum of two individuals comprise the Peer Review Team. ¡ One individual acts as the team lead and must be involved in every part of the process ¡ At least two team members are involved in review of each area reviewed ¡ A peer review checklist for the SWEL development is included as Appendix F 24

REPORTING (CH 8) ¡ Each unit must provide its own report ¡ A list of topics to be included in the submittal report is provided in the guidance ¡ A list of data (including specific tables) included in the report 25

INACCESSIBLE ITEMS (CH 8) ¡ Inaccessible items § A list of inaccessible/delayed items on the SWEL must be submitted to the NRC along with a schedule for completion § An updated report is submitted once the walkdowns are completed § The updated report must include an updated table of the status CAP items 26