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:
cific element. Reviewers should ensure that the success criteria are not so optimistic that they underestimate the required number of components (i.e., overestimate the size of the minimal cutset). c. Evaluation Findings In cases where conclusions are sensitive to the mission success criteria, the staff's safety evaluation report should contain findings equivalent to the following: A technical basis has been established for the mission success criteria used in the analysis. Analytical elements of the technical basis have received an appropriate level of configuration control and quality assurance. Where comparison with analogous criteria from other plants is possible, this comparison has been justified. A.6 Use of Appropriate Data a. Areas of Review In risk-informed applications, it is important that the licensee use appropriate SSC failure data. While plant-specific data is preferred, for plants with little operating history, the only choice might be the use of generic data. Furthermore, when the impact of the change is being modeled as a modification of parameter values, sufficient plant-specific data may not exist to support the modification. The data- related issues are summarized as follows: a) if the impact of the application is to be modeled as a change in parameter values associated with basic events representing modes of unavailability of certain SSCs, these changes should be reasonable and should be supported by technical arguments including plant-specific and generic operational information (when available); and b) the impact of the SRP 19-Al1 change should neither be exaggerated nor obscured by the parameter values used for those SSCs unaffected by the change. b. Review Guidance and Procedures It is to be expected that, for a PRA that has undergone a technical review, parameter values will have been judged to be appropriate, whether they have been evaluated using generic or plant-specific data. However, since the review was focused on the PRA as a base