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:
hould 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 licensing basis change under consideration. As discussed in Section C.2.2 of this guide, the staff’s decision on the proposed license amendment is based on its independent judgment and review. 6.3.1 Risk Assessment Methods To have confidence in the risk assessment used support the proposed change, a summary of the risk assessment methods used should be submitted. Consistent with current practice, information submitted to the NRC for its consideration in making risk-informed regulatory decisions will be made publicly available, unless such information is properly identified as proprietary in accordance with the regulations. The following information should be submitted and is intended to illustrate that the engineering analyses conducted to justify the proposed licensing basis change are appropriate to the nature and scope of the change: • A description of risk assessment methods used. • Documentation showing that the base PRA is acceptable. • A description of the licensee’s process to ensure PRA acceptability and a discussion as to why the PRA is acceptable to support the current application. DG-1285, Page 43 • The key modeling assumptions that are necessary to support the analysis or that impact the application. A modeling assumption is one that is related to a model uncertainty and is made with the knowledge that a different reasonable alternative assumption exists. A reasonable alternative assumption is one that has broad acceptance within the technical community and for which the technical basis for consideration is at least as sound as that of the assumption being made. An assumption is considered “key” when it may influence (i.e., have the potential to change) the decision being made. NUREG-1855 provides useful insights related to this