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:
s used the results of the traditional engineering analyses and the risk assessment to ensure that the submittal fulfills the principles listed in Section II of this SRP chapter. Since the roles played by the traditional analyses and the risk analyses in the decisionmaking process determine the scope, quality, and robustness required of those analyses, examination of the appropriate inputs and assumptions in the analyses may be necessary for reviewers to conclude with reasonable assurance that the proposal fulfills the stated principles. When appropriate, the integrated decisionmaking process should include implementation and monitoring strategies that are used to provide confidence that the results of the underlying engineering analyses remain valid. In addition, licensees can take compensatory measures which reduce risk to offset incompleteness or uncertainties in the analysis. Compensatory measures can also be used to offset a quantifiable increase in risk with non-quantifiable but expected improvements in safety. In addition, the reviewer should ensure that the scope of the proposed changes is commensurate with, and fully supported by, the results of the analyses. That is, the scope of the change should be dependent on the degree of completeness of, level of detail of, and confidence in, the analyses. As an example, if the application concerned changing the treatment of SSCs according to their safety significance, a more detailed PRA model would allow a more detailed categorization into high or low significance than would a less detailed PRA model. Consequently, it would be expected that more SSCs could be characterized as low safety significant in the former case than the latter. It should be noted that both PRAs in this example may be stated to have sufficient quality for supporting the results as they were used in the decision. In this sense, quality can be thought of as a measure of the confidence in the results. To ensure that the important assumptions used