Dry storage systems are one of the storage methods for spent nuclear fuel used in many countries that operate nuclear power plants. To ensure the safe storage of spent nuclear fuel, dry storage systems are designed to maintain radiation shielding, thermal management, and subcritical and mechanical integrity. In addition, these systems must be able to withstand earthquakes, tornadoes, floods, extreme temperatures, and other operating and design-based accident conditions. In order to develop a model with safety and economic feasibility by analyzing various dry storage systems, a vertically dry storage module was proposed, and evaluations were performed on safety evaluation along with design requirements. As a result of the evaluation, all of the safety design requirements were met. This evaluation’s results can be used as basic data for the detailed design of the dry storage module to proceed with further research, including the preparation of a safety analysis report and experimental verification for licensing applications.

This study investigated how welding affects the thermal deformation of square cells produced for casks, which are dry storage containers for spent nuclear fuel. We aimed to minimize structural deformation by utilizing STS316L as the material for the square cells. We explored a method of subdividing the square cells and joining them through butt welding. Keeping the upper plate thickness constant, GTA butt welding was conducted while varying the column’s wall thickness, followed by measurement with a laser vision sensor. The heat conduction and thermal strain were then calculated using a finite element analysis (FEM). Both experimental and analytical results confirmed that there was significant thermal deformation in the cases of thick-walled columns due to variations in heat conduction distribution, with the resulting deformation patterns depending on thickness.

The welding of end plugs to cladding tubes is a critical process in the manufacture of pressurized water reactor (PWR) nuclear fuel rods. The resistance butt welding method is commonly used for this purpose in production. In this paper, we present an analysis of the flow of foreign substances within the weld joint during the tube-cap welding process of PWR nuclear fuel rods, using SORPAS 2D software. The welding process generates foreign substances such as oxide scales, welding fumes, and spatters, which can negatively impact the quality of the weld. Additionally, carbide-based ceramic materials with higher melting temperatures than the base metal have been found within the weld joint in some cases, which can also affect the quality of the weld. To simulate the intrusion of foreign substances with higher melting temperatures than the base material (zirconium alloy) during welding, we conducted a simulation and analyzed the flow of foreign substances. Based on this study, we expected to enhance the reliability and stability of the tube-cap welding process of PWR nuclear fuel rods.