Quantitative evaluation of common cause failures in high safety-significant safety-related digital instrumentation and control systems in nuclear power plants

• A comprehensive quantitative evaluation of common cause failures is performed for safety-critical digital control systems; Both hardware and software are tracked identified; Failure probabilities systems estimated via a multiscale reliability analysis approach. The impact to plant safety evaluated. Digital instrumentation (DI&C) at nuclear power plants (NPPs) have many advantages over analog systems. They proven be more reliable, cheaper, easier maintain given obsolescence components. However, they also pose new engineering technical challenges, such as possibility (CCFs) unique This paper proposes Platform Risk Assessment DI&C (PRADIC) that developed by Idaho National Laboratory (INL). methodology CCFs in high safety-significant safety-related NPPs was part the framework. framework integrates three stages typical risk assessment—qualitative hazard consequence analyses. quantified risks compared with respective acceptance criteria provide valuable insights system architecture alternatives allowing design optimization terms reduction cost savings. case study demonstrate framework's capabilities documented this paper. Results show PRADIC powerful tool capable identify potential digital-based CCFs, estimate their probabilities, evaluate impacts on safety.