Document: NRC Regulatory Guide
Document ID: 2459a562-8984-421c-8058-d096dbb9617c
Document Type: regulatory_guide
Title: Guidelines for Categorizing Structures, Systems, and Components in Nuclear Power Plants According to Their Safety Significance
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0314/ML031430373.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.201
CFR Part: 
CFR Title: 

Content:
lity assumed in the risk sensitivity study of Section 8 of NEI 00-04 and the reliability of safety-significant SSCs is maintained in accordance with their reliability assumed in the analysis) and must encompass more than just the PRA, but also must address the deterministic, traditional engineering (e.g., defense-in-depth), non-PRA type analyses (e.g., seismic margins), and operating modes considerations (e.g., shutdown) of the SSC categorizations under 10 CFR 50.69. 14 23. Section 11.2 NEI 00-04 states that licensees will commit to updating their PRA based on the ASME PRA Standard. As stated in (draft) 10 CFR 50.69, in a timely manner but no longer than every 36 months, the licensee must review changes to the plant, operational practices, applicable industry operational experience, and as appropriate, update their PRA and SSC categorization. NEI 00-04 states that changes to NRC commitments associated with any RISC SSC category should be controlled through NEI 99-04, Revision 1. Since this revision has not been reviewed by the NRC, the statements in NEI 00-04 are not to be taken to be an endorsement of this document by NRC. A licensee must, as part of its submittal requesting to implement 10 CFR 50.69, identify under what conditions they would notify the NRC of changes in RISC categorizations for SSCs and/or resulting treatment. 24. Section 11.4 The NRC concludes that the categorization process implemented via NEI 00-04 must include a provision that provides assurance that future changes in the SSC categorization caused by PRA model changes or other new information will continue to meet the risk acceptance guidelines in RG 1.174 based on a comparison between the new proposed risk-informed program and the original, deterministic special treatment requirements. Thus, the model used in the risk sensitivity study of Chapter 8 must be verified to be representative of the as-built, as- operated plant and the results of this study verified to be acceptable when compared to