Study on water jet penetration behavior in molten LBE during SGTR accident with simulant experiments

Abstract

During Steam Generator Tube Rupture (SGTR) accidents of Lead-bismuth cooled Fast Reactor (LFR), the coolant water in the secondary loop will directly contact with the high temperature molten lead–bismuth eutectic (LBE) in the primary loop around the rupture point resulting in the strong interaction, which may lead to vapor explosion, and eventually damage the structural components of the reactors and cause the possible leakage of radioactive material. In order to further investigate the penetration behavior of water jets in molten LBE, an experimental platform for visualizing the two-phase flow of liquid jets is designed and built, and a series of simulant experiments are conducted by injecting water or ethanol jets into fluorinert FC-40 under different experimental conditions. By analyzing the penetration process of ethanol jet in FC-40, the flow pattern evolution and penetration law of ethanol jet under boiling and non-boiling conditions are obtained. The boiling effect is considered to be the key factor affecting the penetration depth of jet in the range of current experimental conditions. By comparing the injection behaviors of ethanol and water, the consistent flow pattern shows that the injection behavior can be described with the same relation. The results of dimensional analysis method for jet penetration process show that the Froude number theory can reasonably predict the maximum dimensionless penetration depth under different jet conditions.