Numerical Investigation on molten Lead–Bismuth Eutectic solidification characteristics outside vertical tube bundles

•This is the first paper to study the LBE solidification process outside vertical tube bundles.•The transient temperature, solidification fraction and the first blockage location were studied.•The effects of subcooling temperature, Reynolds number and mushy zone parameters were analyzed. The molten Lead–Bismuth Eutectic (LBE) solidification is a critical safety issue in the operation of lead-cooled fast reactors. Under overcooling conditions, the LBE located in the heat exchanger is prone to solidification. However, there are currently no studies on the LBE solidification outside the vertical tube bundles. In this paper, a three-dimensional CFD model of LBE solidification outside the vertical heat exchange tube bundles will be established by using ANSYS FLUENT software. The transient solidification process was analyzed by examining the key parameters including the transient temperature field, solidification fraction and the first blockage location. The effects of the subcooling temperature, Reynolds number and mushy zone parameters on the solidification process were revealed. The findings play an important role in strengthening the understanding of complex solidification behavior in lead-cooled fast reactor.