Fundamental study on heavy metal freezing behavior for stop of water leakage from LWR containment vessel

•Freezing behavior of gallium and Wood's metal were investigated experimentally.•Experiments were made on 2 different plates for observing the behavior of freezing.•Freezing feature is better in case of the structure of higher thermal conductivity.•One-dimensional heat conduction model for static freezing was verified with data.

For the application of heavy metal technology to the stop of water leakage from LWR containment vessel, the freezing behavior of molten heavy metal on a metal plate in water and air environments was investigated. Wood's metal (Pb–Bi–Sn–Cd alloy) and gallium were used as a candidate sealing metal and simulant one, respectively, while brass and stainless steel plates were used as a water-leaking structure. The freezing feature is better in cases of the heavy metal discharged to a water-cooled metal plate with higher thermal conductivity at lower heavy metal temperature in a water atmosphere rather than an air atmosphere. An one-dimensional unsteady heat conduction and freezing model could predict the freezing temperature well, which suggested the capability of simulation of practical freezing phenomena of liquid metal for stop of water leakage with the extention of this model. The present result is useful to develop an equipment for stopping the water leakage in a water environment using heavy metal freezing.