Document: NRC Regulatory Guide
Document ID: 82659041-98b0-4721-b25d-c4fb2ea394d0
Document Type: regulatory_guide
Title: An Approach for Using Probabilistic Risk Assessment in Risk-Informed Decisions on Plant-Specific Changes to the Licensing Basis (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1635/ML16358A153.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.174
CFR Part: 
CFR Title: 

Content:
42 risk-significant SSCs that are not subject to any requirements or the requirements are not commensurate with the SSC’s risk significance. The licensee should also identify: • Key assumptions in the PRA that impact the application (e.g., voluntary licensee actions), elements of the monitoring program, and commitments made to support the application. As defined in the ASME/ANS standard endorsed in RG 1.200, an assumption is labeled “key” when it may influence (i.e., have the potential to change) the decision being made. • SSCs for which requirements should be increased. • Information to be provided as part of the plant’s licensing basis (e.g., FSAR, technical specifications, licensing condition). • Whether provisions of Appendix B to 10 CFR Part 50 apply to the PRA. The latter item comes into play if the PRA forms part of the basis used to enhance or modify safety-related functions of SSCs subject to those provisions. Thus, the licensee would be expected to control PRA activity in a manner commensurate with its impact on the facility’s design and licensing basis and in accordance with all applicable regulations and its quality assurance program description. An independent peer review (as described in RG 1.200) is important in ensuring PRA acceptability. The licensee’s submittal should discuss measures used to ensure the PRA is acceptable for the application PRA, such as a report of a peer review augmented by a discussion of the appropriateness of the PRA model for supporting a risk assessment of the licensing basis change under consideration. The submittal should address any analysis limitations that are expected to impact the conclusion regarding acceptability of the proposed change. The licensee’s resolution of the findings of the peer review should also be submitted. For example, this response could indicate whether the PRA was modified following the peer review or could justify why no change was necessary to support decisionmaking for the