Abstract
Spontaneous vapor explosion can occur when a layer of the high temperature molten material lies on the water pool or on the moisture floor. This is so-called base-triggered vapor explosion. The base-triggered vapor explosion is supposed to occur in the case of a severe accident in various facilities. It is very important to clarify the base-triggered vapor explosion from the viewpoints of the prediction and the prevention of the vapor explosion. In order to evaluate the behavior of the base-triggered vapor explosion, the experimental apparatus is designed and constructed. The experiments using U-Alloy95 as a simulating substance are conducted. Consequently, the behavior of the molten material can be observed in detail with this experimental apparatus. The digital auto-correlation method and PIV are also applied to the visual observation data obtained on the experiments in order to evaluate the velocity distribution of the molten material. Based on the velocity, the pressure at the vapor explosion is also evaluated.
