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Initiating Events Analysis in Operating Phase for Pressurized Water Reactor Nuclear Power Plant


 Probabilistic Safety Assessment (PSA) is an important tool for risk-informed integrated decision making application. Initiating events are caused by equipment failure or/and personnel error which causes disturbance to the nuclear power plant (NPP) and may lead to core damage. As the start of PSA, the quality of initiating events analysis has an important influence on safety assessment and PSA application for NPPs, and the application of operating experience of domestic and aboard are of great importance in initiating events analysis. Based on analysis experience of PSA model in design phase and operation phase for different NPPs, this paper developed a set of method for initiating events analysis of operation phase PSA model development. Combined with the referenced initiating events list, engineering evaluation, operating experience analysis and main logic diagram, a relatively complete initiating events list have been determined. According to the characteristics of the initiating events and analysis requirements for PSA applications, this paper adopted statistical analysis method or specific analysis method to determine the frequency of initiating events which could reflect the design of specific NPPs and operation level of domestic NPPs. The development and application of these initiating events analysis method, which could reflect design and operating characteristics more realistically, improved the development level of PSA model in operation phase effectively, and laid a solid foundation for PSA applications.