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:
ds and Industry PRA Programs One acceptable approach to demonstrate conformance with regulatory position C.1 is to use a national consensus PRA standard or standards, as endorsed by the NRC staff with exceptions and clarifications, that address the scope of the base PRA. ASME and ANS have issued the ASME/ANS Level 1/LERF PRA standard, ASME/ANS RA-Sa-2009, which provides process and technical requirements for an at-power, Level 1 and limited Level 2 LWR PRA for internal hazards (i.e., internal events, internal floods, and internal fire), and external hazards (i.e., seismic, high wind, external flood and other external events). ASME and ANS have also issued ASME/ANS RA-S Case 1, which provides a proposed alternative set of requirements related to the requirements for seismic PRA in Part 5 of the ASME/ANS Level 1/LERF PRA standard. These national consensus PRA standards establish requirements for what an acceptable base PRA should include, including acceptable process requirements; however, these PRA standards do not address how to meet the requirements for an acceptable PRA. Because ASME and ANS joint national consensus PRA standards as well as PWROG- 19027-NP, Revision 1, use the term “requirement,” “require,” and other similar mandatory language, the staff’s endorsement, including staff exceptions and clarifications, mirrors this language. The use of this language in this RG is not intended to convey that that compliance with this RG is mandatory, provides the only way to meet the statutory and regulatory requirements, or that these requirements would be applied to licensees absent their adoption and consistent with the requirements of 10 CFR 50.109. Regulatory position C.2.1 of this RG provides the staff position on the use of a national consensus PRA standard to meet regulatory position C.1. To demonstrate acceptability of the PRA, a peer review is needed to determine if the intent of the requirements in the national consensus PRA standard is met, as