Drop Analysis of Waste Transfer Flask

The present paper describes the drop analyses performed on a waste transfer flask using LS-DYNA® finite element software. Radioactive waste generated during retubing of CANDU®6 reactors are placed in waste containers. Waste transfer flasks are used to transfer waste containers from the reactor building to storage structures. The waste transfer flask is a complex mechanical assembly made of double wall steel shells filled with lead. At the storage area, the waste transfer flask is lifted by a crane to transfer the waste container to the storage structure. During lifting of the waste transfer flask, it is necessary to know the consequence of an unlikely drop event. Analyses have been performed to assess the structural response of the waste transfer flask subjected to impact loads due to various drop events resulting from lifting of the waste transfer flask at the storage area. The waste transfer flask is dropped by considering various orientations viz., dropping on edges, corners and base. Based on the drop analysis the mode of failure and plastic deformation of various components of the waste transfer flask and the waste container is predicted. Also, an assessment is made regarding the structural integrity of the waste container and its retrievability after various drop events.