Simulation of molten metal penetration and freezing behavior in a seven-pin bundle experiment

Analysis of a hypothetical core disruptive accident is important in the safe design of the future generation of reactors such as liquid-metal-cooled reactors. This study determines the fundamental mechanisms underlying the penetration and freezing behavior of molten metal flowing through a seven- pin channel. We conducted a series of simulant experiments that focused on the fuel-pin-bundle geometry under various thermal conditions of the molten metal and pins, and produced data for the fundamental verification of the safety analysis code SIMMER-III. The liquid penetration length and the solidified frozen metal in the flow channel were investigated in the experiments. Visual information was obtained using a digital video camera. A numerical simulation using the SIMMER-III code was carried out to validate its model and method in terms of the bulk freezing behavior of molten metal. The simulation showed that the code reasonably represents the melt penetration and freezing behavior observed in the experiments.