Impact Simulation Analysis of Spent Fuel Assembly Drop Accident

Abstract:
This paper takes spent fuel assemblies of nuclear power plants as the research object. Based on the software HyperMesh and LS-DYNA, the three-dimensional finite element model of the assemblies with bilinear elasto-plastic intrinsic relationships of the material is built up to simulate the assemblies fall process by the explicit dynamics analysis approach. The impact simulation result shows that the maximum stress occurs at the joint between the guide tube and the lower tube holders, which exceeds the material yield strength. Therefore, the structural integrity of the assembly is assessed using strain failure and deformation failure methods and the results show that it meets the safety requirements. The method and conclusions can be a reference for the safety evaluation of the spent fuel assembly transfer process.