ML24345A052

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Presentation for Public Meeting to Discuss Revision of Regulatory Guide 1.200 and Updates to Technical Guidance Related to Risk-Informed Activities, December 16, 2024
ML24345A052
Person / Time
Issue date: 12/16/2024
From: Jeffery Wood
NRC/RES/DRA/PRB
To:
References
RG-1.200
Download: ML24345A052 (1)


Text

Public Meeting to Discuss Revision of Regulatory Guide 1.200 and Updates to Technical Guidance Related to Risk-Informed Activities December 16, 2024

Meeting Agenda Topic Presenter Time (EST)

Meeting introduction Jeffery Wood, NRC 1:00 - 1:15 pm Update on NRC PRA Methods Database Chris Hunter, NRC 1:15 - 2:15 pm Update on NRC PRA Standards Database and NRC Staff Positions Website Jeffery Wood, NRC Demonstration of database websites Austin Glover, Sandia National Laboratories Status of Regulatory Guide 1.200 Revision Jeffery Wood, NRC 2:15 - 3:00 pm Updates to NRC Technical Guidance and Reference Documents (NUREG-1855, NUREG-2122)

Jeffery Wood, NRC Open discussion 3:00 - 3:30 pm 2

Presentation on PRA Methods Database Chris Hunter, NRC 3

NRC PRA Methods Database Chris Hunter Sr. Reliability and Risk Engineer Performance and Reliability Branch Division of Risk Analysis Office of Nuclear Regulatory Research 1

2 Key Messages

  • The U.S. Nuclear Regulatory Commission (NRC) probabilistic risk assessment (PRA) methods database has been developed as knowledge management tool for NRC staff.

- The database is publicly available on the Sandia National Laboratories (SNL) website at https://prastandards.sandia.gov/pra-methods-report/.

- A demonstration will be provided after the NRC presentations.

  • The database is not a regulatory decision-making tool.

- It is knowledge management tool that was designed to aid newer reviewers to efficiently determine the background of a particular PRA method.

3 Database Maintenance

  • The database has a feature that allows users to provide feedback.

- No recommendations on changes, corrections, and/or additions have been provided to date.

  • Existing contract with Pacific Northwest National Laboratory (PNNL) has limited funds available to perform revisions.

- A plan for long-term maintenance still needs to be developed.

- Need to work with industry stakeholders on a plan to ensure NRC database and the Electric Power Research Institute (EPRI) Wiki are synchronized to the extent possible.

4 Possible Future Work

  • The NRC database has very limited information on methods specifically used for high winds, external flooding, and other hazards.

- NRC and PNNL do not have access to documentation in these areas.

  • Is there an opportunity for collaboration with industry who may have more experience and access to the necessary documentation in these areas?

Questions?

5

NRC Staff Positions Database Site

  • Website and database contents prepared by Sandia National Labs
  • Provides access to NRC staff positions on PRA standards from:
  • This tool provides ability to:
  • Search key words
  • Sort and filter
  • Export contents to table or document 4

Demonstration of PRA Methods and PRA Standards Staff Positions Websites Austin Glover, Sandia National Laboratories 5

Regulatory Guide 1.200 Discussion Agenda

  • Projected schedule for RG 1.200 revision
  • Update of PRA and risk-related reference documents 6

Regulatory Guide 1.200 Background

  • Establish NRC staff positions on PRA for LWRs
  • Endorse consensus PRA standards, with staff exceptions and clarifications
  • Endorse related PRA guidance
  • Obviate need for in-depth review of PRA
  • Support other application-specific RGs 7

RG 1.200

Purpose:

one approach acceptable to NRC staff for determining whether a base PRA is sufficient to provide confidence in the results, such that the PRA can be used in regulatory decisionmaking for light-water reactors (LWRs).

Scope of RG 1.200 Revision

  • NRC is expecting to review and endorse:
1. Latest revision of Level 1 / LERF PRA Standard, ASME/ANS RA-S-1.1-2024
  • Published March 2024
  • Previous revision RA-S-1.1-2022 has also been reviewed by NRC staff
2. Level 2 PRA Standard, ASME/ANS RA-S-1.2-2024
  • Published June 2024
3. Advanced LWR PRA mandatory appendix to ASME/ANS RA-S-1.1-2024
  • Under development
4. Low Power and Shutdown PRA Standard
  • Under development

Outside of Scope of RG 1.200 Revision

  • The following PRA standards for LWRs are not currently planned for endorsement in RG 1.200:
  • Level 3 PRA Standard
  • Multi-Unit PRA Standard 9

RG 1.200 Revision Approach

  • Review PRA standards with focus on consistency with previous staff positions
  • Key inputs to remain consistent with previous positions:
  • Some differences in positions expected due to, e.g., different scope, technology, pre-operational requirements
  • Past NRC comments on PRA standards ballots 10

Revision of RG 1.200 Status Endorsement of PRA standards to support:

  • New and advanced LWRs
  • All hazards and all operating modes
  • Design-stage PRA 11 RIDM Established staff positions in existing Regulatory Guides Review 2024 Level 1 / LERF PRA Standard Review Level 2 PRA Standard Review Advanced LWR PRA Standard mandatory appendix (anticipated in 2026)

Review Low Power and Shutdown PRA Standard (anticipated in 2026)

New and adv. LWR applications complete on-going

Projected Schedules for RG 1.200 Revisions RG 1.200, Rev. 4, Level 1/LERF and Level 2 PRA Standards endorsed 2024 2025 2026 L1/LERF Review Complete Draft Guide Mid-2025 RG 1.200, Rev. 4 Early 2026 RG 1.200, Rev. 5, LPSD Standard and Adv. LWR appendix endorsed 2026 2027 2028 RG 1.200, Rev. 5 Early 2028 Adv. LWR Review Early 2027 LPSD Review Mid-2026 Level 2 Review Feb. 2025 Draft Guide Mid-2027

Potential Impacts of Rulemaking Activities

  • Proposed rule title: Alignment of Licensing Processes and Lessons Learned from New Reactor Licensing
  • DG-1395 (ADAMS ML22041A234) was prepared in April 2022 to revise RG 1.200 with changes consistent with the proposed rule
  • Commission has issued direction on proposed rule on Nov. 20, 2024
  • NRC staff will evaluate need for changes in the next Draft Guide of RG 1.200 to support the final rule
  • Not expected to impact NRC draft staff positions on PRA standards requirements 13

Summary RG 1.200 Revision

  • NRC staff are preparing RG 1.200 revision for endorsement of:
  • 2024 Level 1 / LERF PRA Standard - Staffs review is complete
  • 2024 Level 2 PRA Standard - Staffs review is ongoing
  • Endorsements of PRA standards for Advanced LWRs and Low Power /

Shutdown are anticipated in a future revision after completion of those standards

  • Next steps:
  • NRC staff will continue review of Level 2 PRA Standard
  • Follow-up public meeting and update on RG 1.200 revision by mid-2025 14

NUREG-1855 Update

  • Guidance on Treatment of Uncertainties Associated with PRAs in Risk-Informed Decision Making, Rev. 1, March 2017
  • Guidance aligns with PRA uncertainty requirements in 2009 Level 1/LERF PRA standard
  • Update status
  • Updating to incorporate 2024 Level 1 / LERF PRA standard and Level 2 PRA standard with support from Pacific Northwest National Laboratory
  • Addressing areas of emerging needs for advanced LWR PRA uncertainties, if identified
  • No significant changes to the overall framework are anticipated
  • Planning to coordinate public comment period and publication of NUREG-1855, Rev. 2 with RG 1.200 revision schedule.

15

NUREG-2122 Update

  • Glossary of Risk-Related Terms in Support of Risk-Informed Decisionmaking, November 2013
  • Update status
  • Identified approximately 200 new or revised terms and definitions
  • Sandia National Laboratories is assisting in preparing the NUREG revision
  • Not anticipating a need for public comment on the update
  • Targeting publication by September 2025 16

Questions / Discussion 17