Dynamic impact characteristics of KN-18 SNF transport cask - Part 1: An advanced numerical simulation and validation technique

Domestic and international regulations for the transportation of radioactive materials strictly prescribe the design requirements for spent nuclear fuel (SNF) transport casks. According to the applicable codes, a transport cask must withstand a free-drop impact of 9 m onto an unyielding surface and a free-drop impact of 1 m onto a mild steel bar. However, the structural performance of a transport cask is not easy to evaluate precisely because the dynamic impact characteristics of the cask, which includes impact limiters to absorb the impact energy, are so complex. In this study, a more advanced and applicable numerical simulation method using the finite element (FE) method via the commercial FE code LS-DYNA is proposed and verified against the experimental results for a 1/3-scale model of the KN-18 SNF transport cask, recently developed in Korea. In addition, the detailed dynamic impact characteristics of the transport cask under free-drop conditions are investigated via the proposed numerical simulation method and actual drop tests to improve the accuracy and optimization of the SNF transport cask design.