Suppression Features of a Vapor Explosion with Prototypic Reactor Materials

Abstract

The suppression of a vapor explosion is reviewed from a void fraction point of view from previous research results and the results of an experiment and analysis for TROI using a prototypic reactor material. In a tin-water system, a high fraction of air which played the role of steam reduced the peak pressure of a steam explosion. According to the sensitivity analysis that was carried out with an increase in vapor volume fraction, an energetic vapor explosion hardly took place in a mixture with a high void fraction. Under higher vapor fraction conditions ( v > 0:3), the vapor explosion was very weak. The prototypic corium showed a relatively high void fraction compared to ZrO 2 , which is known as an explosive material, because this corium system generates many smaller particles compared to the ZrO 2 system. Also this corium system showed a relatively low explosivity compared to the ZrO 2 system because the high void fraction of the corium system prevents contact between water and hot melt drops in the triggering stage. When considering the experimental results for the role of air instead of steam, an air supply system to provide a high volume fraction during a premixing process can radically prevent and/or mitigate a steam explosion.