Simulation of Spent Fuel Assembly Transport Vertical Drop Based on LS-DYNA

Abstract

The finite element technology is used to carry out the drop simulation and safety assessment of the spent fuel assembly and its transport cask. In view of the problem of how to reasonably simplify the finite element model, a more reasonable and accurate multistage simplified model is proposed for the spent fuel assemblies packed densely in the transport cask, which needs to be analyzed synchronously when dropping. First, the “key” spent fuel assembly is retained, and the “unimportant” assembly is simplified as a cylindrical entity. Based on this, the structure will continue to be simplified and a 1/4 near-earth model containing all characteristics will be established. Then, the LS-DYNA software is used for explicit dynamic analysis of vertical drop conditions. It is concluded that the failure risk of the spacers is the greatest. Therefore, the purpose of this paper is to propose a multistage simplified method for spent fuel assembly and its transport cask, which can provide a reference for the structural integrity analysis of the spent fuel assembly transport drop conditions.