Advanced digital instrumentation and control (DI&C) systems offer important benefits for nuclear power plants, including enhanced reliability, monitoring, and control capabilities. At the same time, they introduce challenges for risk assessment, particularly in identifying digital failure modes, estimating component reliability, and addressing common-cause failures in probabilistic risk assessment. Idaho National Laboratory, under sponsorship from the U.S. Nuclear Regulatory Commission (NRC), conducted a DI&C reliability study using nuclear industry operating experience data from the Institute of Nuclear Power Operations’ Industry Reporting and Information System and the NRC’s Licensee Event Report databases.
This paper summarizes the key findings of the study, provides an overview of DI&C systems and their application in nuclear power plants, reviews prior DI&C reliability research, and presents insights from analyses of these databases. In addition, the paper discusses approaches for integrating DI&C failure events into existing reliability databases and for supporting DI&C reliability estimation and common-cause failure modeling.