ML23137A435
| ML23137A435 | |
| Person / Time | |
|---|---|
| Issue date: | 05/19/2023 |
| From: | Jeffery Wood NRC/RES/DRA/PRB |
| To: | Reisi-Fard M NRC/RES/DRA/PRB |
| References | |
| RG-1.200 | |
| Download: ML23137A435 (4) | |
Text
May 19, 2023 MEMORANDUM TO: Mehdi Reisi Fard, Chief Performance and Reliability Branch Division of Risk Analysis Office of Nuclear Regulatory Research Signed by Wood, Jeffery FROM: Jeffery J. Wood, Senior Risk Analyst on 05/19/23 Performance and Reliability Branch Division of Risk Analysis Office of Nuclear Regulatory Research
SUBJECT:
SUMMARY
OF MAY 2, 2023, PUBLIC MEETING TO DISCUSS REVISION OF REGULATORY GUIDE 1.200 AND UPDATES TO TECHNICAL GUIDANCE RELATED TO RISK INFORMED ACTIVITIES On May 2, 2023, the U.S. Nuclear Regulatory Commission (NRC) held a public meeting with stakeholders. The announcement for this public meeting is available at the [(Agencywide Documents and Access and Management System) (ADAMS) Accession number ML23110A002]. The subjects of this meeting were the staffs revision of Regulatory Guide (RG) 1.200, Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities, and updates to technical guidance documents related to risk-informed activities. The enclosure to this document lists the meeting attendees. The staffs presentation slides are available in ADAMS at ML23121A255.
The purpose of this meeting was to discuss the plans for revisions to RG 1.200 including endorsement, with the staffs exceptions and clarifications, of national consensus standards for probabilistic risk assessment (PRA). The staff also discussed plans for updates to technical guidance in NUREG-1855, Guidance on the Treatment of Uncertainties Associated with PRAs in Risk-Informed Decision Making, and NUREG-2122, Glossary of Risk-Related Terms in Support of Risk-Informed Decisionmaking. Attendees, which included representatives of the nuclear industry and other stakeholders, had an opportunity to provided comments on the planned revisions and updates.
Enclosure:
List of Attendees for May 2, 2023, Public Meeting to Discuss Revision of Regulatory Guide 1.200 and Updates to Technical Guidance Related to Risk-Informed Activities CONTACT: Jeffery Wood, RES/DRA (301) 415-0953
M. Reisi Fard In its remarks, the NRC staff provided background on the purpose and past revisions of RG 1.200. The staff presented the plans for revising RG 1.200 including reviewing and endorsing four consensus PRA standards. The plans include review and endorsement of the following PRA standards:
ASME/ANS RA-S-1.1-2022, Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment for Nuclear Power Plant Applications, ASME/ANS RA-S-1.2, Severe Accident Progression and Radiological Release (Level 2)
PRA Standard for Nuclear Power Plant Applications for Light Water Reactors (LWRs),
(expected to be published in 2023),
ASME/ANS RA-S-1.5, Requirements for Advanced Light Water Reactor Probabilistic Risk Assessment, (expected to be published in 2024), and ASME/ANS RA-S-1.6, Requirements for Low Power and Shutdown Probabilistic Risk Assessment, (expected to be published in 2024).
The staff presented a proposed schedule for reviewing the PRA standards and holding future public meetings to discuss draft staff positions on the standards.
The staff also described their work on tools and guidance to improve staff efficiency in their reviews related to risk-informed applications and PRA methods. The staff described the development of a PRA standards database and a catalog of PRA methods. The staff described the plans for updating PRA technical guidance documents NUREG-1855 and NUREG-2122.
After the staff presentation, the meeting attendees were given the opportunity to ask questions and provide comments. Comments were provided by representatives from the Nuclear Energy Institute and Southern Nuclear Company (SNC) about the PRA standards that are planned for endorsement in RG 1.200. During the discussion, commenters noted that there are no anticipated applications that would use some of the PRA standards planned for endorsement, with the low power and shutdown PRA standard (i.e., ASME/ANS RA-S-1.6) mentioned specifically.
NRC staff members noted that applicants are required to develop a Level 1 and a Level 2 PRA covering all modes and all initiating events for which NRC-endorsed consensus standards on PRA exist under NRC Regulations Title 10, Code of Federal Regulations, Part 52 (i.e., 10 CFR Part 52). The lack of endorsed standards for Level 2 and low power and shutdown PRA has resulted in a gap in the guidance on an acceptable approach to develop PRAs with this scope.
NRC staff members also noted that the expectations for developing a low power and shutdown PRA standard and endorsement in an NRC regulatory guide have been a part of the staffs plan for implementing the phased approach to PRA quality, as described in Commission paper SECY-04-0118 (ADAMS Accession number ML041470505).
As the meeting continued, a representative from SNC asked about how the endorsement of new PRA standards would impact current license holders under 10 CFR Part 52 and if there could be any potential regulatory backfit issues. NRC staff are evaluating the impacts of the RG 1.200 revision on current licensees and future applicants, but RG 1.200 and its revisions do not introduce or change the existing regulatory requirements. The NRC staff will continue to engage with stakeholders on the potential impacts of the RG 1.200 revision throughout the revision process.
M. Reisi Fard A representative from Holtec requested additional guidance regarding how the PRA standards should be used with new and advanced designs. The discussion highlighted that the advanced light water reactor PRA standard could be used for developing a PRA during stages of the reactor design, but at some point, the PRA development and maintenance should transition to using the PRA standards that were developed for use with operating reactors. NRC staff are considering ways to clarify the applicability of the PRA standards for licensing applications at different design and operational stages. These topics will be discussed in future public meetings.
The meeting was concluded when no further comments or questions were identified from the participants. The NRC staff will consider the comments as their work on revising RG 1.200 proceeds. As discussed during the meeting, NRC staff will schedule future public meetings to discuss the progress on the RG 1.200 revision and gather additional feedback.
ML23137A435; ML23137A435 OFFICE RES/DRA/PRAB RES/DRA RES/DRA/PRAB NAME JWood JW MReisi-Fard MR JWood JW DATE May 19, 2023 May 19, 2023 May 19, 2023