Document: NUREG-0800
Document ID: 4f0d611c-d3fb-43e5-ab91-e7f7b4de3511
Document Type: srp
Title: Determining the Technical Adequacy of Probabilistic Risk
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0406/ML040630300.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.1
CFR Part: 
CFR Title: 

Content:
ance to the NRC staff on how to determine that the PRA results being used in a decision are supported by the underlying analysis. It must be clear that the elements of the model used to generate those results are of sufficient technical quality and that the assumptions and uncertainties that have the potential to affect the results have been evaluated as being appropriate. III.1 Scope of Review In order to perform the review for quality, the reviewer should first understand the context in which the PRA is being used. III.1.1 Use of the PRA in the Application The reviewer should become familiar with the way the PRA is used in the application. This includes: • identification of the SSCs, operator actions, and plant operational characteristics affected by the application • a description of the cause-effect relationships between the change and the above SSCs, operator actions, and plant operational characteristics • mapping of the cause-effect relationships onto PRA model elements 5 • definition of the acceptance criteria or guidelines, including identification of the PRA results that will be used to compare against the acceptance criteria or guidelines and how the comparison is to be made. III.1.2 Scope of Risk Contributors Addressed in the PRA Model Based on the definition of the application, the scope of risk contributors (internal and external initiating events, modes of plant operation) of the PRA can be identified. For example, if the application is designed around using the acceptance guidelines of Regulatory Guide 1.174, the evaluations of core damage frequency (CDF), CDF, large early release frequency (LERF), and LERF should be performed with a full-scope PRA, including external initiating events and all modes of operation. However, since most PRAs do not address this full scope, the decision makers must make allowances for these omissions. Examples of allowances include the introduction of compensatory measures, restriction of the implementation of the