A Post-accident Operating State Monitoring and Tracing System for Primary Circuit in Nuclear Power Plants

To fulfill the requirements of tracing and controlling the unit state for post-accident conditions in Nuclear Power Plants (NPPs), a post-accident primary circuit operating state monitoring and tracing system is designed based on the characteristics of the unit operation under Incident and Accident Conditions (IAC). The system, which will be integrated into the plants' Digital Control System (DCS), can automatically trace and display primary circuit state (pressure and temperature) to assist the operators to trace the state evolution process and trend of the primary circuit clearly and intuitively. In addition, the system zones the unit state under IAC into several operating ranges according to various limit conditions for post-accident operation, which can provide support for the operators while implementing Emergency Operating Procedure (EOP) as each operating range is assigned to a specific operation strategy. The system will be beneficial to improve the efficiency of EOP implementation, to effectively reduce the operator human errors under IAC, as well as to optimize the human-machine interface (HMI) design of EOP.