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:
gnificance 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 Subsections III.2.2.2 and III.2.2.3 of this SRP section). 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. Subsection III.2.1 of this SRP section presents review guidance on these topics. 19.2-79 June 2007 For SSCs not modeled in the PRA, reviewers should verify that the licensee’s process determined that the following conditions apply for each SSC that has been proposed as a candidate for relaxation or removal of current requirements: • The SSC does not perform a safety function, or does not perform a support function to a safety function, 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. • 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 result in unintentional releases of radioactive material even in the absence of severe accident conditions. If any of the above conditions apply, or if SSC performance is difficult to quantify, the licensee should have used a qualitative evaluation process to determine the impact of relaxing requirements on equipment reliability and performance. This evaluation should include identifying those failure modes for which the failure rate may increase, and those for which detection could become more difficult. Reviewers should then verify that the licensee provided