Numerical Analysis of In-Vessel Retention using MARS-Ga for APR1400 under the Ga-based External Reactor Vessel Cooling

To stabilize and terminate the severe accident through enhancing the coolability of the degraded core, this paper introduces an approach to avoid heat removal limit by replacing flooding material from the borated water to the liquid metal, gallium. The attractive properties such as the low melting point, high boiling point, and no reaction with water ensure that gallium can play an important role in nuclear safety as an alternative coolant in the gap between the vessel and the vessel insulation. The properties of liquid gallium compared to other materials are indicated. For the investigation on the effect of gallium for IVR-ERVCS, numerical simulation for severe accident in APR 1400 using MARS-LMR was performed. In this study, the numerical analysis of gallium-based IVR-ERVCS using MARS-LMR was performed. The range of temperature distribution in this system was considered as an important factor and then the possibility of ERVC using liquid gallium was confirmed. In addition, It will perform the sensitivity studies for the heat transfer area between liquid gallium and borated water to design the optimum ERVC using liquid gallium