Consideration of Impact Behaviour of Radioactive Packages onto Real Targets

According to the IAEA Regulations for the Safe Transport of Radioactive Materials, a 9 m drop test is required for a type B packages as a test condition which simulates accidents in transport, e.g., fall, crash of the packages lAEA, 1985). The target provided for this drop test is an unyielding object surface; therefore, all kinetic energy of the dropping packages just before the impact is absorbed by the deformation of the packages. On the other hand, in the occurrence of real accidents, the object hardness needs to be considered. Since the packages can strike object surfaces such as concrete abutments, roadbeds, hard soil, and water, a part of the kinetic energy of the dropping packages just before the impact is absorbed by the deformation of the object surface. Consequently, it is expected that the hardness of the objects affects the impact response of the packages greatly. For example, the same impact force on the packages can be generated by a low-velocity impact on a hard object or a high- velocity impact on a soft object. In this study, drop tests onto various object surfaces were performed using a 48Y -cylinder in order to clarify the relation between the object surface hardness and the associated impact response of the packages. Moreover, the Distinct Element Method (DEM) was applied to simulate the dynamic fracture impact behaviours of the real targets, and the effectivness of this method was investigated.