Development of a PAS module in the ATHROC for simulation of passive containment air cooling system

In advanced pressurized water reactors (PWR) employing the passive containment air cooling system (PAS), heat can be removed from the containment to the atmosphere. This paper established a comprehensive mathematical and physical model to simulate PAS and developed a modular PAS module based on the ATHROC to analyze its thermal–hydraulic characteristics. The accuracy of the code was validated by comparing the calculated temperatures and pressures with data obtained from GOTHIC. The results showed that differences were less than 5%, confirming the reliability of the PAS module. Then the thermo-hydraulic analysis of AP1000 containment system with PAS during a loss-of-coolant accident (LOCA) was performed using ATHROC. The findings indicated that when LOCA ocurs, the internal temperature and pressure of the containment can be maintained below the design limits. This study confirms that the PAS module possesses the capability of the thermal–hydraulic analysis of the passive containment air cooling system.