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:
the probability of failure to repair the SSC in time to prevent core damage as a function of the accident sequence in which the SSC failure appears. DA-E1 thru DA-E3 -------------------- No objection -------------------- DG-1362, Appendix A, Page A-15 Table A-2. Staff Position on ASME/ANS RA-Sa-2009 Part 2, Technical and Peer Review Requirements for At-Power Internal Events Index No Issue Position Resolution 2-2.7 - QU 2-2.7.1 SRs for LERF quantification reference the SRs in 2-2.8, and therefore, need to be acknowledged in 2-2.8. Clarification The objectives of the quantification element are to provide an estimate of CDF (and support the quantification of LERF) based upon the plant-specific… (b) significant contributors to CDF (and LERF) are identified such as initiating events… Table 2-2.7-1 HLR-QU-A, HLR-QU-B, HLR-QU-C, HLR-QU-E, HLR-QU-F -------------------- No objection -------------------- Table 2-2.7-1 HLR-QU-D SRs for LERF quantification reference the SRs in 2-2.8 and, therefore, need to be acknowledged in 2-2.8. Clarification …significant contributors to CDF (and LERF), such as initiating events, accident sequences… Tables 2-2.7-2(a) thru 2-2.7-7(f) QU-A1, QU- A4, QU-A5 -------------------- No objection -------------------- QU-A2 Need to acknowledge LERF quantification Clarification …consistent with the estimation of total CDF (and LERF) to identify significant accident… QU-A3 The state-of-knowledge correlation should be accounted for all event probabilities. Left to the analyst to determine the extent of the events to be correlated. Need to also acknowledge LERF quantification Clarification Cat I: ESTIMATE the point estimate CDF (and LERF) Cat II: ESTIMATE the mean CDF (and LERF), accounting for the “state-of-knowledge” correlation between event probabilities when significant (see NOTE 1). Cat III: CALCULATE the mean CDF (and LERF) by … DG-1362, Appendix A, Page A-16 Table A-2. Staff Position on ASME/ANS RA-Sa-2009 Part 2, Technical and