[1E01-07] Severe Accident 1

[1E05] Estimation of the In-Depth Debris Status of FukushimaUnit-2 and Unit-3 with Multi-Physics Modeling

(15)Local Debris Status Indicated by the MPS Analyses of VULCANO VF-U1 Experiment

*Takanari Fukuda¹, Akifumi Yamaji¹, Xin Li¹ (1. Waseda Univ.)

Keywords:MCCI, decommissioning of Fukushima Daiichi reactors, fuel debris, MPS method, VULVANO VF-U1 experiment

The MPS method has been developed and applied to the numerical analysis of VULCANO VF-U1 experiment to investigate possible mechanisms, which characterized the post-test metallic phase distributions along the concrete sidewall. The results indicated key parameters, such as the differences in densities and solidification temperatures of the metallic and the oxidic phases. Consideration of the local upward flow near the concrete sidewall affected and induced by melting of the concrete and gas from concrete thermal decomposition was necessary. Since the highlighted mechanism is scale-independent, similar distributions of the metallic phases may be expected in the 1F Unit-3 pedestal, if the local temperature reached such high temperature as simulated in the experiment.