System Safety Analysis Method Based on Real-Time Online Risk Monitoring Technology

In the continuous operation process of Nuclear Power Plant (NPP), its configuration is full of variety over time because of the system’s dynamic characteristics. There is a great need to update the risk/safety analysis models when it becomes necessary to reflect those dynamic characteristics of the system/component. Most of the current methods for risk/safety analysis belong to the scope of safety pre-analyzing, which analyzes the system risk/safety before system being in service. The main purpose of these safety pre-analyzing is to guide system design and optimization, but the real-time operational risk/safety analysis of NPPs is considered little. In order to know well the real-time risk/safety for system, a System Safety Analysis Method based on Real-time Online Risk Monitoring Technology is proposed. The safety risk model is established based on the modular fault tree that is used to represent logic structure of system. The real-time risk/safety is monitored according to the correspondence monitoring signal or data of component/system. Simultaneously the method can account for the change of risks based on the established mapping relationship between the state transition rules and corresponding risk/safety model updating rules. Finally, a case monitoring the safety for the system of two redundant pumps was used to demonstrate the effectiveness of the method.