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:
aff has no objection to the requirement. • No objection with clarification. The staff has no objection to the requirement. However, certain requirements, as written, are either unclear or ambiguous, and therefore the staff has provided its understanding of these requirements. • No objection subject to the following qualification. The staff has a technical concern with the requirement and has provided a qualification to resolve the concern. Table B-1 provides the staff’s position on each requirement. A discussion of the staff’s concern (issue) and the staff proposed resolution is provided. In the proposed staff resolution, the staff clarification or qualification to the requirement is indicated in either bolded text (i.e., bold) or strikeout text (i.e., strikeout); that is, the necessary additions or deletions to the requirement (as written in ASME/ANS RA-S Case 1) for the staff to have no objection are provided. DG-1362, Appendix B, Page B-2 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 Section 5-1 5-1.1 to 5-1.2 -------------------- No objection -------------------- 5-1.3 The last paragraph of the section states that the internal events PRA model is the starting point “…to which must be added a number of structures, systems, and components (SSCs) not included in the model but that could fail due to the external hazard.” Failure modes caused by the external hazard for SSCs existing in the internal events PRA should also be included. Clarification The approach to any external hazard PRA typically uses as its starting point the internal-events PRA model to which must be added a number of structures, systems, and components (SSCs) not included in the model but that could