Document: NUREG-0800
Document ID: e32f0820-4e33-476e-aa36-4ca8c2c64af0
Document Type: srp
Title: Use of Probabilistic Risk Assessment in Plant-Specific, Risk-Informed Decisionmaking:
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0119/ML011940192.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.0
CFR Part: 
CFR Title: 

Content:
ti~tjte for a proposed relaxation in current requirements. The compensatory measures should also become part of the plant's licensing basis. Technical information basis for applications involving risk quantification or risk categorization The staff expects that tl e information base supplied to the integrated decisionmaking panel will be capable of supporting the findings that should be made in the context of the specific risk-informed application. For example, in risk quantification and risk categorization applications, the following guidelines should be applicable. At least the Level 1 portion of the internal events PRA should be formulated in such a way as to support quantification of a change in risk (ACDF and ýLERF) and importance measures, and should provide qualitative information (e.g., minimal cutsets) adequate 1:o support defense-in-depth findings. SRP 19-B2 There should be an inventory of plant response capability for probabilistically significant operating modes and initiating event categories (internal, external, flood, fire, seismic, etc.). Given a full-scope Level 2 PRA, this requirement could be satisfied by an inventory of event tree success paths, with an indication of the mission success criteria, systems, and SSCs involved in each path. Lacking a full-scope Level 2 PRA, surrogate information should be developed for unanalyzed areas, along the lines described in Section 111.2.2.2 of this SRP chapter. This requirement is necessary in order to show the safety functions performed by SSCs (or other plant elements) affected by the application. Causal models (determination of cause-and-effect relationships) should be developed to support an evaluation (qualitative or quantitative) of the change in risk as a function of the application. This is necessary in order to relate the application to actual risk indices. Documentation of inputs to the decisionmaking panel should be part of the process. Reviewers should verify the scope and depth of the