A Study on the Modeling Technique for Cask in Free Drop Impact Condition

The package used to transport radioactive materials, which is called by cask, must be safe under normal and hypothetical accident conditions. These requirements for the cask design are verified through test or finite element analysis. Since the cost for FE analysis is less than one for test, the verification by FE analysis is mainly used. But FE analysis may show different results for the same problem due to several assumptions of modeler to simplify real states and modeling technique. Materials of the components make elastic plastic or elastic perfectly plastic behavior under the considered conditions due to the large deformation, impact and contact mechanism. This behavior is simulated with difficulty and may have different results as FE codes. In this paper, finite element analysis is carried out for the 9 meters free drop and the puncture condition of the hypothetical accident conditions using LS-DYNA3D and ABAQUS/Explicit. Energy and effective stress on each component are presented and compared between two FE codes where, the effective stress is designated the maximum von Mises stress on inner and outer shell. While the similar results are obtained from energy plot, results on stress are shown some differences between the two codes.