The Research on the Risk Monitor With Specific Plant Configuration at Shutdown Mode for VVER Nuclear Reactor

The research and application of Risk Monitor is one of the most influential analysis tool in the field of probabilistic safety analysis (PSA) of nuclear power plants. Risk Monitor is often used in nuclear power plant operation risk management, scheduled maintenance risk management or other plant activities, aims to help the formulation of power plant integrated decision-making from the risk-informed perspective. The VVER nuclear reactors have four redundant trains to achieve relatively higher safety level, compared to other nuclear power plants design. Because of its four redundant systems design, the configurations of certain system, particularly for the shutdown mode are various. This paper takes the VVER residual heat removal system (JNA) as an example and discusses the method of developing the average PSA model into a risk monitor PSA model for VVER JNA at shutdown mode. Meanwhile, this paper establishes the cases of different JNA setting configurations, aims to support the plant configuration risk management analysis from the perspective of risk level.