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:
for excluding the plant-systems analyst from the walkdown. The second part of the SR starting with “EVALUATE the consequences…” is expected to capture the “risk-importance” of the identified interactions. Table 5-2.2-6 Introductory text -------------------- No objection -------------------- SFR-E1 -------------------- No objection -------------------- SFR-E2 For CC I: The intent of the requirements should be to identify relevant failure mechanisms. In CCI conservative assumptions and data may be used. Qualification For SSCs identified in SPR-C4 SPR-C6 that significantly contribute to seismic core damage frequency and/or seismic large early release frequency, conservatively IDENTIFY relevant failure modes mechanisms of structures, equipment, and soil. ENSURE that the assumptions and data used in the identification are conservative. SFR-E2 For CC II: The examples listed in the requirement confuse the differences between CCI and CCII. The only real difference is that CCI says ‘conservatively IDENTIFY relevant’ while CCII says ‘IDENTIFY relevant and realistic’. This SR references SPR-C4 but should reference SPR-C6. Clarification For those SSCs identified in SPR-C4 SPR-C6 that significantly contribute to seismic core damage frequency and/or seismic large early release frequency, IDENTIFY relevant and realistic failure mechanisms modes of structures, equipment, and soil. SFR-E3 For CC I: seismic fragility Qualification ESTIMATE conservative seismic DG-1362, Appendix B, Page B-17 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 estimates should be conservative. Ensuring the fragility estimate is conservative may require the development of a more realistic estimate to