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:
entially similar, it is arguably necessary to consider common cause failure. Thus, a program that addresses common cause failure potential by monitoring component performance may provide the necessary protection against loss of the function, while still allowing a decrease in some level of commitment on the individual members of the group. Verification of low safety significance: In evaluating the qualitative risk-informed categorization, reviewers should consider the integrated decisionmaking process and criteria used by the licensee. In reviews of the licensee's determination of low safety significance for SSCs or operator actions, reviewers should verify that the licensee appropriately applied risk importance measures and accounted for the results of sensitivity studies. Reviewers should also verify that the licensee considered and compensated for factors such as potential inadequate scope and level of detail of the PRA (see Sections 111.2.2.2 and 111.2.2.3 of this SRP chapter). Finally, reviewers should verify that, in categorizing an SSC or operator action as low safety significance, the licensee considered the defense-in-depth philosophy and available safety margins. Section 111.2.1 of this SRP chapter presents review guidance on these topics. For SSCs not modeled in the PRA, reviewers should verify that the licensee's process determined that the followving conditions apply for each SSC that has been proposed as a candidate for relaxation o' removal of current requirements: The SSC does not perform a safety function, or does not perform a support function to a safety functioi, or does not complement a safety function. The SSC does not support operator actions credited in PRAs for either procedural or recovery actions. The failure of the SSC will not result in the eventual occurrence of a PRA initiating event. SRP 19-C6 The SSC is not a part of a system that acts as a barrier to fission product release during severe accidents. The failure of the SSC will not