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:
egulatory position C.2.2 of Section C of this RG), it should be determined whether the change to the PRA is PRA maintenance or a PRA upgrade, which includes the use of an NDM. Since PRA maintenance is defined as a change to the PRA that does not meet the definition of a PRA upgrade, the classification process is focused on determining whether a change to the PRA is a PRA upgrade, which includes use of NDMs. The definitions of the terms PRA upgrade, state-of-practice, PRA method, consensus method, and NDM are provided in the Glossary of this RG. Consistent with these definitions, a change to the PRA is considered a PRA upgrade when the change results in the: 1. application of a PRA method previously used in the peer reviewed plant PRA that a. causes one or more supporting requirements in a national consensus PRA standard to be applicable that were not applicable in the previous peer review (i.e., including changes in capability category; or b. is being applied in a different context 2. application of a method not previously used in the peer reviewed plant PRA that a. is a consensus method or an NDM that has been subjected to an NDM peer review or, b. has been developed separately from a state-of-practice method or involves a fundamental change to a state-of-practice method (i.e., an NDM) Changes related to list item 2.b require an NDM peer review, consistent with regulatory position C.2.2.2.2 in Section C of this RG. Consistent with the above criteria for classifying a change to the PRA as PRA maintenance or a PRA upgrade and the definitions in the Glossary of this RG, the NRC staff endorses, with the following exception, the guidance provided in Section 3 of PWROG-19027-NP, Revision 1, “Newly Developed Method Requirements and Peer Review” (Ref. 24), as one acceptable DG-1362, Appendix C, Page C-2 approach for determining whether a change to a PRA model is classified as PRA maintenance or a PRA upgrade. The description of Step 2 of the process in Section 3 of