The research on the heat transfer of a solid-core nuclear reactor cooled by heat pipe through a numerical simulation, considering the assembly gaps

Abstract The solid-core nuclear reactor cooled by the heat pipe has received extensive attention in recent years. It is mainly applied in the space reactor power system which can supply ample energy for the demand of the surface power on extraterrestrial planets. Based on this technology, a number of reactor designs have been proposed since 1990 s. Unlike liquid-cooled reactors, the heat transfer in a solid-core reactor has to go through the assembly gaps which could cause the considerable thermal contact resistance. The thermal contact resistance might limit the heat transfer and change with the expansion of the fuel pin in the core during the startup process. A numerical simulation was conducted to calculate the unsteady startup process of the core and analyze the influence of the thermal contact resistance caused by the assembly gaps. The results showed that the size of the initial assembly gaps might change the way of the heat transfer in the core and determine the temperature difference between the core and the heat pipe.