Development of numerical simulation method for relocation behavior of melting fuel in nuclear reactors, 2; Prediction of relocation behavior for molten debris with heating

Yamashita, Susumu   ; Takase, Kazuyuki; Yoshida, Hiroyuki  

In the Fukushima accidents, fuel assemblies which were installed in the reactors were reached a high temperature by stop of the core cooling system with a power station black-out. As a result, it is considered that the core degradation has been introduced because the melting of the fuel rods occurred and the melting behavior was expanded. In order to elucidate a progress of the melting phenomena in the reactor core, a numerical simulation code which can be precisely evaluated the melting phenomena is required. Then, the melting behavior of the fuel assemblies in the reactor core was analyzed numerically using the three-dimensional multi-phase thermal-hydraulic simulation code. In the presentation, the numerical results on the melting behavior of molten debris including heating source and not have it which suppose Uranium fuel and reactor core internals.