Common Cause Fault Rates for Instrumentation and Control Assemblies: Estimates Based on Licensee Event Reports at U.S. Commercial Nuclear Power Plants, 1976-1978.

摘要

This report presents estimates of common cause fault rates and related quantities, based on Licensee Event Reports of instrumentation and control assemblies in nuclear reactors. The Licensee Event Report data base is briefly described, and imperfections in the data are discussed. The components are grouped into assemblies, for which rates are estimated. For estimating rates, the binomial failure rate model is used, extended to allow for the substantial observed plant-to-plant variability, and for shocks that by their nature cause all the assemblies in a system to fail. Every quantity is estimated by both a point estimate and a 90 percent interval. All rates are expressed per calendar hour.