Document: NRC Regulatory Guide
Document ID: 22ccfd5e-c5d8-4615-a02c-32369aa9f533
Document Type: regulatory_guide
Title: Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1930/ML19308B636.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.200
CFR Part: 
CFR Title: 

Content:
5-2.2-5 Introductory text -------------------- No objection -------------------- SFR-D1, SFR-D2 -------------------- No objection -------------------- SFR-D3 For CC I: In general, the walkdown AND the fragility evaluation provide the assurance. This requirement supports that assurance but may not always ensure. Also, “vulnerability” needs to be defined. Clarification IDENTIFY seismic vulnerabilities low seismic capacities and to ensure ENSURE that assumptions and the use of generic seismic fragilities are conservative. SFR-D3 For CC II: The current language implies realistic and plant specific fragilities for all vulnerabilities, which is inconsistent with SFR-E3 and established practice. Clarification IDENTIFY seismic vulnerabilities to ensure and ENSURE that the seismic fragility calculations can be realistic and plant-specific as needed. DG-1362, Appendix B, Page B-15 Table B-1. Staff Position on ASME/ANS RA-S Case 1, “Case for ASME/ANS RA-Sb-2013 Standard for Level 1/Large Early Release Frequency Probabilistic Risk Assessment of Nuclear Power Plant Applications,” Technical and Peer Review Requirements of a Level 1, Seismic PRA for the At-Power Operating Mode Index No Issue Position Resolution SFR-D4 The walkdown should also focus on operator pathways and potential unavailability of those pathways. SFR-D7 seems to refer to consequences of failure of one SSC on the performance of another SSC including inoperability of the SSC by and operator action. However, the words added here refer to pathways for ex-control room actions. Clarification FOCUS on potential functional and structural failure modes, equipment anchorage, and support load paths, and pathways necessary for performing required ex-control room actions. SFR-D5 -------------------- No objection -------------------- SFR-D6 In 2009 (SFR-E3) indicates that if component screened out during or following the walkdowns, document anchorage calculation and provide the basis. However, this statement is