Effect of metal layer height on heat transfer inside molten pool

Abstract

Abstract In a serious accident, after the core of a nuclear reactor melts and collapses, In-Vessel Retention in the External Reactor Vessel Cooling (IVR-ERVC) is an effective technology to maintain the integrity of lower head by reducing heat load on it. The various factors affecting the melting of the lower head have been widely studied. The mass of the molten metal layer may affect the consequences of the accident, since it is where the focusing effect occurs. However, the related research is still absent. In this paper, we systematically calculated the heat transfer behavior and melting process under different metal layer heights conditions. The temperature distribution, the velocity distribution, the heat flux of the outer wall of the Reactor Pressure Vessel (RPV), and the change of the thickness of the RPV were obtained through Large Eddy Simulation (LES). Interestingly, the heat flux increases with the metal layer height at first and achieve the maximum in the middle height. These results increase the understanding towards the serious accidents.