A T-H Model for Residual Heat Removal System Reliability Analysis

Passive system is widely used in new generation nuclear power plant (NPP) such as AP1000 and high-temperature gas-cooled reactor in order to improve the safety of NPP. Since system operation relies on natural force, and both the driven force and resistance are influenced by many uncertain factors, physical process failure becomes one of the significant contributors to the system operation failure, which need to be considered in system reliability. For system physical process failure analysis, the thermal-hydraulic (T-H) model should be established to describe the system performance, namely the system can operate successfully or not. And the T-H model should be fast enough to be used in the system reliability analysis,In this paper, the T-H model of passive residual heat removal system (PRHR) in the AP1000 for analysing the system reliability is described. The accuracy and the validity of the model have been proved by comparing the results with the requirements of AP1000 design. Finally, the connection between residual power and flow rate in AP1000 PRHRS is analysed.