Development of reliability monitor by GO-FLOW methodology for the safety related sub-systems in PWR

Abstract

In this study, how to define the dynamic reliability of nuclear power plant is first discussed and then development of reliability monitor for safety related subsystem in PWR is conducted by considering the redundancy of safety system in new concept of risk monitor system. New concept of risk monitor system of Nuclear Power Plant (NPP) is based on the idea of plant Defence-in-Depth (DiD) risk monitor and reliability monitor to monitor what degree of safety functions incorporated in plant’s system is maintained by multiple barriers of DiD. The reliability monitor has been developed by implementing the Plant DiD risk monitor’s conditions. The example analysis is conducted by using GO-FLOW program, a computer code to evaluate dynamic reliability of system, to obtain the dynamic reliability curve of the containment spray system in PWR. It is shown by GO-FLOW analysis that the redundant system configuration increases the reliability of the system.