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:
udes the use of an NDM in a PRA. Appendix C provides the guidance for determining whether a change to the base PRA is a PRA upgrade or a PRA maintenance and, if it is a PRA upgrade, whether the change involves the use of an NDM. The incorporation of an NDM results in a PRA upgrade because it involves the application of a method not previously used in the peer reviewed plant PRA. The staff position for the peer review of a PRA upgrade is discussed in regulatory position C.2.2.2.1. The peer review of an NDM is performed to assess whether the NDM can be used to support a PRA. The peer review of an NDM focuses on the NDM itself rather than the implementation of the NDM in a PRA. The staff position for the peer review of an NDM is discussed in regulatory position C.2.2.2.2. 2.2.2.1 Peer Review of a PRA Upgrade The peer review of a PRA upgrade is a focused-scope peer review in that it only involves reviewing the changes to the PRA model as a result of the upgrade to the PRA model. The Glossary in this RG provides a definition for PRA upgrade. A PRA upgrade can include: • Application of a method not previously used in the peer-reviewed plant PRA • Implementing a method in a different context • Implementing changes that support any supporting requirements previously not reviewed or previously not applicable The guidance for the peer review for a PRA upgrade in NEI 17-07, Revision 2, is endorsed by the NRC in this RG. 2.2.2.2 Peer Review of a Newly-Developed Method The peer review of an NDM assesses whether the NDM meets a set of technical requirements and consequently can be used to support the PRA. Section 5.1 of the Pressurized Water Reactor Owners DG-1362, Page 44 Group (PWROG) report PWROG-19027-NP, Revision 1, “Newly Developed Method Requirements and Peer Review,” provides a set of technical requirements for Section 1-6 of the ASME/ANS Level 1/LERF PRA standard. NRC endorsement of this document is provided in regulatory position C.2.2.3 and C.2.2.4 of this