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:
by the application. This monitoring should be performed as the proposed application is phased in. For very reliable SSCs, it may be necessary for the licensee to review available operating experience at other plants for applicability to the licensee's plant to expand the operating experience database. Reviewers should ascertain that the monitoring program is capable of demonstrating that the performance of the components or systems is in accordance with what has been assumed. c. Evaluation Findings Reviewers should verify that information provided and review activities conducted support the following conclusions: The failure rates and probabilities used, especially those that directly affect the proposed application, appropriately consider both plant-specific and generic data that are consistent with generally accepted values from PRAs of similar plants, and deviations (if any) have been justified on the basis of plant-specific factors. The licensee has systematically considered the possibility that individual components could be performing more poorly than the average associated with their class, and has avoided relaxation for those components to the point where the unavailability of SRP 19-A13 the poor performers would be appreciably worse than that assumed in the risk analysis. The changes to the parameter values impacted by the application are both justified and reasonable. Data used to sup:)ort changes to the plant's design or operations are supported by an appropriate performance monitoring program. A.7 Modeling of Common Cause Failures a. Areas of Review Common cause failures (CCFs) represent the failures of components that are caused by common influences such as design, manufacturing, installation, calibration, or operational deficiencies. Since CCFs can fail more than one component at the same time and can occur with greater probability than would be predicted by the product of the individual component failure probabilities, they can significantly