While establishment of appropriate policies and securing key technologies on spent nuclear fuels are state-of-the-arts in the world due to saturation of fuel pools and/or temporary facilities, the details of transportation, storage and repository are different depending on the situation in each country. Thereby, accurate integrity assessment of specific transportation casks and contained fuel assemblies as well as their breakdown effects on the public and environment are becoming more important.
The purpose of this study is to carry out parametric stress analyses of spent nuclear fuel assembly in a prototypal dual purpose cask under development. As the representative postulated accident conditions, four scenarios were selected such as vertical, horizontal, corner and oblique drop from 9 m height on the ground. Then, taking into account computational cost, a simple model that considers only the equivalent mass of the fuel assembly was made for preliminary finite element analyses to determine the most dangerous drop condition and critical location. Subsequently, a detailed model that considers the acceleration of fuel assembly was made based on the preliminary analysis results and finite element analyses were carried out to calculate engineering parameters. Resulting membrane and bending stress intensities were compared with allowable design limits, of which findings will be used as technical background for development of transportation cask and management of the spent nuclear fuel integrity.