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:
lopment and Use of an Acceptable Probabilistic Risk Assessment The staff positions in Regulatory Positions C.1 through C.1.4 represent the minimum capability the staff has determined that a PRA should possess to support risk-informed regulatory activities. When this RG is used to determine the acceptability of a PRA, all staff positions in this RG should be met for a more efficient review by the staff and for a PRA to be considered acceptable. One acceptable approach for demonstrating conformance with regulatory positions in this RG and thereby reducing the need for an in-depth staff review of the PRA is to use an NRC-endorsed national consensus standard during the development of the PRA and to have the PRA peer reviewed through an NRC-endorsed process. The ASME/ANS NLWR PRA standard provides the technical requirements for this purpose. If the ASME/ANS NLWR PRA standard is used, as endorsed by the NRC in Appendix A to this RG, Regulatory Positions C.1 through C.2 are considered to be met. Deviations from a staff endorsement of a PRA technical requirement or a staff position are evaluated for acceptability on a case-by-case basis. When the exceptions raised by the staff are taken into account, the national consensus standard or PRA peer review process in question is considered to be acceptable for its intended purpose. If the PRA is demonstrated to have met the requirements of these documents, with attention paid to the NRC’s exceptions, it can be assumed that the analysis is technically correct. Thus, the staff should be able to focus more on the assumptions and approximations associated with the application. In that way, the need for a detailed review by NRC staff of the PRA should be reduced. When deviations from these documents exist, the applicant should demonstrate either that its approach is equivalent or that the influence on the results used in the application is such that no changes occur in the risk contributors. As discussed in Regulatory Position C.2.2