Thermal-hydraulic and stress analysis of AP1000 reactor containment during LOCA in dry cooling mode

Abstract

Some kinds of break in the reactor coolant system may cause the coolant to exit rapidly from the failure site, which leads to the loss of coolant accident (LOCA). In this paper, a stress analysis of an AP1000 reactor containment is performed in an LOCA, with the passive containment cooling system (PCCS) being available and not available for cooling the wall’s containment. The variations in the mechanical properties of the wall’s containment, including elastic modulus, strength, and stress, are analyzed using the ABAQUS code. A general two-phase model is applied for modeling thermal-hydraulic behavior inside the containment. Obtained pressure and temperature from thermal-hydraulic models are considered as boundary conditions of the ABAQUS code to obtain distributions of temperature and stress across steel shell of the containment in the accident. The results indicate that if the PCCS fails, the peak pressure inside the containment exceeds the design value. However, the stress would still be lower than the yield stress value, and no risk would threaten the integrity of the containment.