An integrated framework for analysing operational events in China nuclear power plants

Operational events of nuclear power plants (NPPs) are safety-relevant incidents, which may impair the plant functionality and lead to undesired consequences. Thus, their analysis is important for the safety assessment of NPPs. Although several studies have been conducted on NPPs operational events, there is a lack of an integrated framework that effectively combines qualitative and quantitative analyses of operational events. In this study, a framework for the identification and quantification of root causes of operational events is proposed. The framework includes the root causes identification procedures and an online quantification tool based on Bayesian Network modeling. Thirty-seven unplanned reactor trip (URT) events occurred in Chinese NPPs have been used for the case study and the outcome indicates that this framework can be quite useful: on the one hand, it can support inspection and control of the measures of prevention of operational events and reduction of their occurrences from the perspective of regulatory authorities; on the other hand, it can be embedded within the national nuclear safety administration (NNSA) experience feedback (EF) system as an online support tool for living safety assessment.