Research of aerosol removal by passive containment cooling system

Abstract

Passive containment cooling system (PCCS) can effectively remove the heat from the containment and maintain the pressure and temperature in case of accident, thus ensuring the containment integrity. PCCS introduces thermophoresis and diffusiophoresis aerosol deposition and changes the distribution of fission products in the containment, thus affecting containment dose evaluation and off-site source term assessment. In this paper, a Generation III PWR nuclear power plant model with PCCS is established by using ASTEC (Accident Source Term Evaluation Code), and the removal effect of PCCS on fission product aerosol is studied under the large break loss of coolant accident. The results show that one train of PCCS can increase the aerosol removal factor for approximately 0.05/h. Taking five trains of PCCS in this study as an example, aerosol deposition effect introduced by PCCS reduces suspended aerosol in containment by 10 %–20 %, and the effect is more significant in the PCCS-locating compartment. Meanwhile, the gas flow among compartments changes the aerosol mass in the adjacency of the PCCS-locating compartment. This phenomenon weakens the removal effect in the PCCS-locating compartment and make the aerosol concentration in adjacent compartments tend to be consistent.