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

THE NTTF 2.3 SEISMIC WALKDOWNS OF US NPPS Lessons and Insights

SMiRT 22 Special Session

• n Seismic

reevaluation of

• perating US

NPPs based on NRC Fukushima Task Force Topics 2.1 & 2.3 August 2013

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

PRESENTATION TOPICS

NEAR TERM TASK FORCE (NTTF)

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SEISMIC NTTF ACTIVITIES OVERVIEW

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Ongoing Near term Long term 2.3 2.1 2.2 Walkdowns Hazard evaluation Risk evaluation Regulatory Actions 10 year update

Walkdowns to assure plants are meeting licensing basis and to look for potential seismic

• issues. Reports due November 2012. Some

equipment delayed until outages. Hazard evaluation due in 18 months for NPPs within the CEUS SSC model area. 3 years for western US NPPs performing SSHAC level 3

• studies. Plant-specific site response.

Risk results due 3-4 years after hazard. SMAs

• nly allowed for small exceedance levels. SPRAs

allowed for all exceedances, but required for large exceedances. After receiving the information from the SPRA and SMA analyses, the NRC will determine appropriate regulatory actions. Rulemaking to require a reevaluation every 10 years. 11/2012 (+outages) 9/2013 (CEUS) 3/2015 (WUS) 3 years after hazard Depends on findings Rulemaking timeline

Based on the 50.54(f) letter:

NTTF ACTIVITIES

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¡ 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 st stra rategies, maintenance plans, and identify degr degraded, ded, nonconf nonconform

• rming,

ing, or una

• r 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.

¡ Steps outlined in Enclosure 3 “Seismic Walkdowns”

• Gather information per the Staff Requirements

Memorandum (SRM) for SECY-11-0124

• Develop methodology and acceptance criteria
• Perform walkdowns
• Address potential deficiencies
• Verify adequate monitoring and procedures

NTTF ACTIVITIES

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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

• ther purpose.

Recommendation 2.1 reevaluations use:

§ EPRI 1025287 (SPRA) § NRC ISG JLD-ISG-2012-04 (SMA) § EPRI/NP-6041-SLR1 (SMA)

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NTTF ACTIVITIES

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¡ As per 50.54(f) letter, report should include

• Plant hazard licensing basis
• Walkdown process
• IPEEE vulnerabilities and actions taken to

eliminate or reduce them

• Walkdown results and key findings
• Detailed description of actions taken for

potential vulnerabilities

• Planned or installed protection features
• Impact of peer review

Defines R2.3 Objectives and Reporting (incorporated into guidance)

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)

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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

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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

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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

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DEVELOPING THE SWEL (CH 3)

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Exclusion Criteria Inclusion Criteria Exclusion Criteria Inclusion Criteria SWEL 1 SWEL 2

Figure 1-1 Figure 1-2

Limits items to what is important Limits items to what is important Broad sampling

• f Plant

Broad sampling

• f Plant

DEVELOPING THE SWEL (CH 3)

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SWEL

SWEL 1 SWEL 2

Figure 1-1 Figure 1-2

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) § Variety of environments § Equipment enhanced due to IPEEE program

¡ Sampling a pragmatic approach to limited time to conduct the walkdowns

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Inclusion Criteria

INCLUSION CRITERIA SWEL 2 (CH 3)

¡ Inclusion Criteria for Sampling

¡ Same as SWEL 1 but without IPEEE upgrades SWEL 2 also includes…

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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.

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WHAT ARE WALKDOWNS VERSUS WALK-BYS? (CH 4)

¡ Walkdowns are intensive visual inspection of a piece

• f 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.

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WHAT ARE WALKDOWNS VERSUS WALK-BYS? (CH 4)

¡ Walk-bys are…

§ visual examinations of an area that consider the

• verall 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.

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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

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WALKDOWN CHECKLIST (APP C)

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Checklists are set up so that all the answers indicating “no problems” are “yes”

ADDRESSING POTENTIAL ISSUES (CH 5)

¡ Potential issues identified in the walkdowns go to licensing basis evaluations ¡ If not easily dispositioned, item is added to the CAP ¡ All open items at time

• f reporting go into

the CAP

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Figure 1-3

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.

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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

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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

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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

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RESIDENT INSPECTOR TEMPORARY INSTRUCTION

¡ Resident Inspectors carried out a review and

• bservations as described in TI/2515-188

¡ The objective of the TI is to independently verify that the licensee’s seismic walkdown activities were conducted using the endorsed guidance ¡ Limited to SWEL development and the conduct of a small sampling of walkdowns ¡ Value principally in the oversight at the time of the SWEL development and walkdowns. Resident Inspectors were limited by NRC standard processes in terms of reporting findings

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RESIDENT INSPECTOR TEMPORARY INSTRUCTION

¡ Reviewed SWEL for consistency with guidance ¡ Walkdowns and walk-bys performed with the licensee and independently ¡ Walkdown with licensee

• Choose two to four items from the SWEL and observe walkdowns

and associated walk-bys

¡ Independent inspector walkdown

• Choose one to three items from the SWEL
• Either use the licensees completed checklists OR complete the

form independently and check against the licensees checklist. 28

MAJOR OUTCOMES AND INSIGHTS

¡ All Licensees submitted reports November of 2013 ¡ Nearly 1700 items were entered into CAPs; however, no major issues have surfaced. Reviews are ongoing. ¡ Many resident inspectors noted the benefit of training for seismic issues that was conducted for TI/2515-188. ¡ Although there were only 1/3 as many walk-bys as walkdowns, nearly half the CAP items were identified in the walk-bys. ¡ Several types of equipment and specific issues arose (next slides). The NRC will probe this information to better understand the deficiencies and to determine if regulatory changes are needed.

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SEISMIC WALKDOWN INSIGHTS

Me Metric ric

Items submitted to LBR or CAP ~1900 Items submitted to CAP ~1700 Plants reported putting items directly into CAP and not performing LBEs ~70% Items closed out of CAP at time of reporting ~50% CAP items coming from area walk-bys versus equipment walkdowns ~50% Mean number of CAP items 19 Median number if CAP items 15

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CAP SUBMITTALS BY EQUIPMENT

Equipment ¡Classifica1on # ¡Items % ¡of ¡Items # ¡of ¡NPPs ¡(of ¡104)

• 0. ¡Other

32 4% 26

• 1. ¡MCCs ¡and ¡Wall-­‑Mounted ¡Contactors

60 7% ¡ 37

• 2. ¡Low ¡Voltage ¡Switchgear ¡and ¡Breaker ¡Panels

29 4% ¡ 21

• 3. ¡Medium ¡Voltage, ¡Metal-­‑Clad ¡Switchgear

10 1% ¡ 10

• 4. ¡Transformers

24 3% 17

• 5. ¡Horizontal ¡Pumps

54 7% 30

• 6. ¡VerMcal ¡Pumps

24 3% 19

• 7. ¡PneumaMc-­‑Operated ¡Valves

44 5% 26

• 8. ¡Motor-­‑Operated ¡and ¡Solenoid-­‑Operated ¡Valves

53 7% 41

• 9. ¡Fans

24 3% 19

• 10. ¡Air ¡Handlers

24 3% 21

• 11. ¡Chillers

13 2% 10

• 12. ¡Air ¡Compressors

7 1% 5

• 13. ¡ ¡Motor ¡Generators

2 <1% 2

• 14. ¡DistribuMon ¡Panels ¡and ¡AutomaMc ¡Transfer ¡

Switches 43 5% 24

• 15. ¡BaUery ¡Racks

22 3% 15

• 16. ¡BaUery ¡Chargers ¡and ¡Inverters

42 5% 26

• 17. ¡Engine ¡Generators

12 1% 9

• 18. ¡Instrument ¡Racks

57 7% 34 19 ¡Temperature ¡Sensors 5 1% 4

• 20. ¡Instrumenta1on ¡and ¡Control ¡Panels

151 19% 52

• 21. ¡Tanks ¡and ¡Heat ¡Exchangers

71 9% 42

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CAP BY WALK-BY CATEGORY

Issue ¡from ¡Walk-­‑by # ¡Items % ¡of ¡Items # ¡of ¡NPPs ¡(of ¡104) Adverse ¡anchorage ¡condiMons 91 12% 42 Degraded ¡equipment/hardware ¡(examples ¡ are ¡missing ¡parts, ¡corrosion, ¡lighMng ¡fixture ¡ issues, ¡leaks) 158 21% ¡ 52 Seismic ¡interacMon ¡(spaMal, ¡fire, ¡flooding) 206 28% ¡ 57 Other ¡housekeeping ¡issues ¡(temporary ¡ installaMons, ¡portable ¡equipment) 136 18% ¡ 47 Cable/conduit ¡raceways ¡and ¡HVAC ¡ducMng 9 1% 7 Other ¡issues 14 2% 11 Nature ¡of ¡issue ¡idenMfied ¡during ¡the ¡walk-­‑by ¡ could ¡not ¡be ¡determined ¡from ¡report 134 18% ¡

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ADDITIONAL INFORMATION

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ACRONYMS

¡ CAP Corrective action program ¡ EPRI Electric power research institute ¡ IPEEE Individual Plant Examination for External Events ¡ NTTF Near term task force ¡ SFP Spent fuel pool ¡ SSEL Safe shutdown equipment list ¡ SWE Seismic walkdown engineers ¡ SWEL Seismic walkdown equipment list ¡ SQUG Seismic Qualification Utility Group ¡ TI Temporary instruction

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KEY DOCUMENTS

¡ NTTF Report published July 2011 ¡ SECY-11-0124 recommended actions w/o delay - September 2011 ¡ SRM for SECY-11-0124 issued October 2011 ¡ SECY-11-0137 establishes prioritization of activities - issued October 2011 ¡ SRM for SECY-11-0137 issued December 2011 ¡ SECY-12-0025 authorizes 50.54(f) ¡ The 50.54(f) letter

§ Issued March 12, 2012 § To all operating power reactor licensees § Establishes a timeline and actions

¡ EPRI Guidance 1025286 issued May 2012