Verification on loss of main feed water flow accident of advanced PWR

AP1000 is a PWR power reactor with 1,154 MW of electrical power that is designed based on the proven performance of the other Westinghouse PWR designs. To prepare the role of Center for Reactor Technology and Nuclear Safety as a Technical Support Organization (TSO) in terms of reactor safety verification, the verification activities have been carried out for the AP1000 that begins with failure of secondary coolant accident verification. The activity started with the technical safety features modeling such as passive core cooling system consisting of a Passive Residual Heat Removal system (PRHR), Core Makeup Tank (CMT), and In-containment Refueling Water Storage Tank(IRWST). The failure of secondary coolant accident selected is the loss of main feed water flow to one of the steam generator simulated using the calculation program RELAP5/SCDAP/Mod3.4. The objective of analysis is to obtain sequences of changes in the thermalhydraulic parameters in the reactor due to the selected event. Analysis results obtained are validated and compared with the analysis results using the calculation program LOFTRAN in the AP1000 safety design document.The verification results show that the loss of feed-water supply has no impact on core damage, the reactor coolant system, as well as secondary systems. The ability of heat exchanger PRHR has been verified to dissipate decay heat of the core after reactor trip. Validation with the AP1000 safety design document shows compliance on most thermal hydraulic parameters. In general, the advanced PWR model equipped with passive core cooling system that has been developed remains safe in the event of loss of secondary coolant flow accident. (author)