Stiffness analysis of new spacer grid model for metal 3D additive manufacturing

Currently, the Republic of Korea operates a total of 28 nuclear power plants, including those under construction. Although every part of a nuclear power plant is important for safe operation, most attention is paid to the nuclear fuel assembly. The assembly is divided into fuel rods containing fuel assembly fuel and spacer grids. The spacer grid is an important component for core cooling by keeping the fuel rods protected and spaced apart. The spacer grid is produced from a strap bar, which is the base plate, and by spot welding eight edges of the strap bar. However, the spot welding machine has a large capacity and power supply such that the welding quality varies depending on the weld metal and surface conditions. As a result, the welding point may be defective. Therefore, this study aims to analytically verify the performance of a newly designed spacer grid for metal 3D AM as well as present analytical criteria for product development.