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:
No Issue Position Resolution 1-A.3, Example 18 Changing the definition of core damage without changing the thermal- hydraulic methodology may result in changed success criteria which could change the accident progression delineated by the accident sequences. It is not a foregone conclusion that this is a simple change to the PRA model. It needs to be reviewed to ensure that the resulting changes are appropriate. Further, what would be a significant change is open to interpretation, and “would be prudent” is not as strong as “should.” Clarification Discussion and/or Alternative Recommendation: While this change may not be a “new methodology,” it could result in changing the success criteria with implications for the development of accident sequences, and potentially on the HRA (through timing), data, and quantification. If this change leads to a significant change in risk insights, a focused peer review should be performed 1-A.3, Example 21 This assumes that the “important” human actions are of the same nature as the new ones being added and utilize the ASEP method in the exact same manner. This cannot be assumed. Clarification Rationale: If it can be shown that the previous “important” human actions fully utilized the ASEP method, and that any deficiencies by the analyst were corrected, then, if there is no significant impact on risk insights, this change falls into ....... 1-A.4 References Clarification See global comment on references at start of Table A-1. DG-1362, Appendix A, Page A-8 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 Section 2-1 2-1.1 thru 2-1.3 -------------------- No objection -------------------- Section 2-2 2-2.1 -------------------- No objection -------------------- 2-2.1 – IE 2-2.1.1 -------------------- No objection -------------------- Table 2-2.1-1 -------------------- No objection --------------------