Experimental study on fragmentation behaviors of molten LBE and water contact interface

Based on the design of CLEAR (China LEAd-based Reactor), it is important to study the molten LBE (Lead-Bismuth Eutectic)/water interaction following an incidental steam generator tube rupture (SGTR) accident. Experiments were carried out to investigate the fragmentation behavior of the molten LBE/water contacting interface, with a high-speed video camera to record the fragmentation behavior of 300–600 ℃ LBE at 20 ℃ and 80 ℃ of water temperature. Violent explosion phenomenon occurred at water temperature of 20 ℃, while no explosion occurred at 80 ℃. Shapes of the LBE debris became round at 80 ℃ of water temperature, whereas the debris was of the needle-like shape at 20 ℃. For all the molten LBE and water temperatures in the present study, the debris sized at 2.8–5.0 mm had the largest mass fraction. The results indicate that the dominant physical mechanism of the molten LBE fragmentation was the Kelvin-Helmholtz instability between LBE/water direct contact interface.