Document: NRC Regulatory Guide
Document ID: cde52d5a-adf9-49be-9d1f-59449dfca895
Document Type: regulatory_guide
Title: TRIAL - Acceptability of Probabilistic Risk Assessment Results for Non-Light Water Reactor Risk-Informed Activities
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2123/ML21235A008.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.247
CFR Part: 
CFR Title: 

Content:
Section 9 of NEI 20-09, Revision 1. A follow-on peer review is performed after the initial peer review of the PRA has already been conducted and at least the F&Os classified as “findings” from the previous peer review have been identified and addressed. A follow-on peer review should be conducted after a PRA has been upgraded. A follow-on peer review’s scope can be as narrow as a single individual SR within a PRA element, or as expansive as a peer review of the entire PRA for a given hazard. When an NDM is used in a PRA, the method should be peer reviewed to determine its acceptability. The peer review of an NDM assesses whether the method meets a particular set of technical requirements and, consequently, can be used to support the PRA. After an NDM has been successfully peer reviewed, its implementation in a PRA is considered to be an upgrade and should therefore be subject to an implementation peer review. An acceptable approach to performing a peer review for an NDM is described in NEI 20-09, Revision 1. In particular, NEI 20-09, Revision 1, states, in part, that, if an NDM is deemed not technically acceptable in the NDM peer review report, or if at least one finding-level F&O on the NDM remains open, a licensee or applicant may not use the method in a PRA supporting risk-informed licensing applications. Because the peer review and F&O finding-level are adequate to determine the acceptability of an NDM, the NRC staff has determined that this provision establishes adequate control over the use of an NDM. If open F&Os from an NDM peer review cannot be successfully closed through an NRC-endorsed closure process, the NDM could be submitted to the NRC to determine its acceptability. The staff recognizes that for certain types of NDMs (e.g., fundamentally novel methods or technologies), some direct review by the NRC staff may be warranted. Submitted applications that use NDMs with open F&Os are subject to review by the NRC to determine the acceptability of the