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:
d and Performance-Based Plan, which is abbreviated as RPP. These activities cover a wide range of PRA applications and involve the use of a variety of PRA methods (with variety including both types of models used and the detail of modeling needed). For example, one application involves the use of PRA in the assessment of operational events in reactors. The characteristics of these assessments rely on model changes or simplifying assumptions to change the PRA models so that they reflect the conditions experienced during an operational event. In contrast, other applications require the use of detailed performance and design information to provide a more realistic model of the plant. The activities described on the agency’s public Internet site1 relate to a number of agency interactions with the regulated industry. With respect to reactor regulation, activities include, for example, developing guidance for NRC inspectors on focusing inspection resources on risk-important equipment and reassessing plants with relatively high CDFs for possible backfit. The principal focus of this RG is on the use of PRA findings and risk insights in decisions on proposed changes to a plant’s licensing basis. One significant activity undertaken in response to the policy statement is the use of PRA to support decisions to modify an individual plant’s licensing basis. Such modifications are related to changes to a plant’s design, operation, or other activities that require NRC approval and could include, for example, exemption requests under 10 CFR 50.12, “Specific exemptions” (Ref. 12) and license amendments under 10 CFR 50.90. This RG does not address licensee initiated changes to the licensing basis that do NOT require NRC review and approval (e.g., changes to the facility as described in the final safety analysis report (FSAR), the subject of 10 CFR 50.59, “Changes, tests and experiments” (Ref. 13)). This RG also makes use of the Commission’s Safety Goal Policy