ML24019A084

NRC Public Meeting Presentation on Risk Insights and Severe Accident Vulnerability Staff White Paper Guidance for LWR CP Applications

ML24019A084
Person / Time
Issue date:	01/31/2024
From:	James Shea NRC/NRR/DNRL/NLIB
To:
References
Download: ML24019A084 (1)

Text

Development of Guidelines for Risk Assessment and Severe Accident Information in a Light-Water Reactor Construction Permit Application 1

January 31, 2024

Purpose

• Provide overview of completed, publicly available, draft white paper, Guidelines for Risk Assessment and Severe Accident Information in a Light Water Reactor Construction Permit Application (ML23326A185)

• Provide an opportunity to external stakeholders to ask questions or comment on the white paper

• Communicate the staffs next steps 2

Participants

• Stacey Rosenberg (co-lead)

• Alissa Neuhausen (co-lead)

• Malcolm Patterson

• Marie Pohida

• Keith Tetter

• Anders Gilbertson

• Marty Stutzke

• Hanh Phan

• Jim Shea (project manager) 3

Agenda

• Background and Objectives

• Internal and External Outreach

• Content Overview

• Next Steps 4

Need for the Effort

• Planned use of 10 CFR Part 50 from near-term applicants

• Staff identified a gap in available regulatory guidance for risk insights and severe accident information in LWR CP applications

• No construction permit applications for nearly 40 years

• Past construction permit applications pre-dated agencys key PRA-related actions

• Three Mile Island Action Plan

• Generic Letter 88-20

• Commissions Policy Statements on Severe Accidents and PRA

• Use of PRA at design-stage 5

Objectives of Guidelines in White Paper

• Scope of information for risk insights and severe accident information in a LWR CPA commensurate with:

- Design readiness at time of CPA submission

- Use of risk insights and information in CPA (e.g., identifying licensing basis events)

• Increase consistency in content for LWR CPAs and predictability of staff review

• Overcome misconception that construction permit applicants must meet endorsed PRA standards 6

Development Approach 7

Information sources such as:

Regulatory Guide 1.70 Regulatory Guide 1.200 Standard Review Plan for Chapter 19 DC/COL-ISG-028 DNRL-ISG-22-001 Internal deliberations

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Collaboration with non-LWR efforts Determine scope of information to support staff review and findings Guidance document Staff initiated public meetings Design-specific pre-application meetings

Internal Collaboration and External Outreach

• Conducted three public meetings (March 2023, July 2023, January 2024)

- About 40 people attended each meeting, including new LWR designers.

- External stakeholders supported our effort at March 2023 meeting.

- We addressed feedback on topics for the white paper

• Advanced reactor staff and new reactor licensing staff contributed to the development of white paper

- Open communication and sharing of similarities or differences in efforts

- Leveraged work on DG 1404, Rev. 1*

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• DG-1404, Revision 1 (proposed new RG 1.253), Guidance for a Technology-Inclusive Content-of-Application Methodology to Inform the Licensing Basis and Content of Applications for Licenses, Certifications, and Approvals for Non-Light-Water Reactors.

Feedback Received from External Stakeholders

• Provide clarity on PSAR content compared to information available in audit

• Consider Advanced Reactor's parallel efforts

• Provide guidance for information in PSAR on different approaches to address external hazards

• Provide guidance on content related to data analysis

• Clarify need for self-assessment compared to peer-review

• Provide guidance on information in PSAR on configuration control program 9

Guidance Content - Minimum Scope Minimally Acceptable* Elements for Internal Events PRA Minimally Acceptable Non-PRA Evaluations Additional Elements Initiating event analysis Plant operating state analysis Internal flood PRA Accident sequence analysis Internal flood assessment Internal fire PRA Success criteria development Internal fire assessment Seismic PRA Systems analysis PRA-based seismic margins High winds PRA Human reliability analysis Non-seismic hazard assessment (includes hazard screening)

External flooding PRA Data analysis Low power and shutdown evaluation Other hazards PRA Level 2 analysis Low power and shutdown PRA Quantification Source term analysis Uncertainty analysis Radiological consequence analysis 10 Capability Category I is acceptable.

Applicant can choose and is encouraged to perform an additional element instead of a non-PRA evaluation

Guidance Content - Non-Seismic Hazards 11 Conservative Estimate of Risk Screen hazard from assessment Can hazard be screened on site-specific basis*?

PRA YES NO OR

• Re-evaluate at OL stage to account for design changes during construction.

White Paper Content - PSAR Information

• Scope of guidance is focused on PSAR content and not technical acceptability of CP-stage PRA

• Scope of information is scaled down compared to DC or COL applications

- Considers design description requirements in 10 CFR 50.34

• Guidelines are presented as bulleted list for each topic

- To assist PSAR preparation, it can be used as a checklist

• Information identified for inclusion in PSAR is primarily

- descriptions, including justifications

- identification of assumptions and limitations

- summary of results and risk insights

• Configuration control program information provides confidence in the applicants ability to track assumptions and changes

• Level of detail is not prescribed to accommodate variation in design maturity 12

Next Steps

• Pursue formalizing guidelines as an appendix to DNRL-ISG-2022-001

- Content is consistent with purpose of ISG

- ISG will provide regulatory stability for staff and applicants

- Public comments will be requested on appendix only because other content remains unchanged

• Staff continues to encourage design-specific pre-application engagements 13

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List of Abbreviations 15 ADAMS Agencywide Documents Access and Management System CFR Code of Federal Regulations COL combined license CP construction permit CPA construction permit application DC design certification DG draft guidance DNRL Division of New and Renewed Licenses ISG interim staff guidance LWR light-water reactor OL operating license PSAR preliminary safety analysis report SSC structure, system, and component

List of References SRM-SECY-2015-0002 Proposed Updates of Licensing. Policies, Rules and Guidance for Future New. Reactor Applications, ADAMS ML15266A023 NUREG-0660, NRC Action Plan Developed as a Result of the TMI-2 Accident, May 1980.

Individual Plant Examination for Severe Accident Vulnerabilities - 10 CFR 50.54(f) (Generic Letter No. 88-20), November 23, 1988 Severe Reactor Accidents Regarding Future Designs and Existing Plants; 50 FR 32138, August 8, 1985 Safety Goals for the Operations of Nuclear Power Plants; 51 FR 28044, August 4, 1986 Use of Probabilistic Risk Assessment Methods in Nuclear Regulatory Activities; 60 FR 42622, August 16, 1995 Regulatory Guide 1.70, Standard Format and Content of. Safety Analysis Reports for Nuclear Power Plants, Revision 3, November, 1978 Regulatory Guide 1.200, Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities, Revision 3, December, 2020 NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants:

LWR Edition - Severe Accidents.

DC/COL-ISG-028, Assessing the Technical Adequacy of the Advanced Light-Water Reactor Probabilistic Risk Assessment for the Design Certification Application and Combined License Application, December 2016 DNRL-ISG-22-001, Safety Review of Light-Water Power Reactor Construction Permit Applications, Interim Staff Guidance, October 2022, ML22189A099 16