Numerical Research on Performance of AP1000 Passive Containment Cooling System Without Falling Film

Passive Containment Cooling System (PCS) is one of the most important passive safety features in AP1000 nuclear power plant. Numerical Simulation of PCS without falling film was conducted using CFD method in this paper to investigate heat transfer performance of PCS. The results indicate that: at the time of 72 hours after break accident, there is no water in passive containment cooling water storage tank (PCCWST), PCS cannot completely remove reactor core decay heat to environment just with the effect of natural convection and thermal radiation; mass flow rate of natural convection and PCS heat removal power increase with the increase of the outside surface temperature of steel containment, but the increasing amplitude of the former is smaller than the latter significantly, and the fraction of thermal radiation in the PCS heat removal power is the smallest when the outside surface temperature of steel containment is 80 °C; mass flow rate of natural convection and PCS heat removal power decrease with the increase of environmental temperature, while the fraction of thermal radiation in the whole heat removal power becomes bigger with the increase of environmental temperature.