Document: NUREG-0800
Document ID: 7916b088-fb90-4163-84fe-027bd315bcc5
Document Type: srp
Title: REVIEW OF RISK INFORMATION USED TO SUPPORT PERMANENT PLANT-
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0717/ML071700658.pdf
Revision Date: 2023-06
Chapter: 19
Section ID: 19.2
CFR Part: 
CFR Title: 

Content:
priate in beyond-single-failure scenarios. Traditionally, development of mission success analyses in PRAs has ranged from the use of faster running models that might not have the same level of quality assurance as the conventional SAR tools to the extrapolation of results from analyses performed on similar plants. In order to satisfy the Commission’s guideline, then, reviewers should find that the licensee has not distorted the PRA insights by using a systematically conservative bias in mission success criteria and that mission success criteria used to justify changes to the plant’s design or operations have a sound technical basis. b. Review Guidance and Procedures When it is determined that the results and conclusions of a risk-informed application are especially sensitive to the choice of mission success criteria, or if the modeling is particularly controversial, reviewers should evaluate the relevant success criteria and the basis for each. If the basis is analytical, it may be appropriate to evaluate the code and the input data used. When it is determined that the computer codes used have not received adequate licensee or other industry review, closer examination of the models should also be considered. 19.2-50 June 2007 The models, codes, and inputs used to determine mission success criteria should meet QA standards that are consistent with generally accepted methods. Standards should include configuration control of the analysis inputs and results. The standards do not have to be the same as the standards applicable to SAR analysis, but they should be explicit (i.e., engineering calculations and codes should be verified and quality assured) and they should be formalized as part of the licensee’s QA program. In cases where the basis for the success criteria is lacking, reviewers should either request additional licensee justification or seek independent analysis. Licensee justification could include the use of alternative plausible models to justify the