Study on the Impact Limiter Design for the Spent Fuel Transport Casks

A shipping cask transporting the spent nuclear fuels of nuclear power plants should secure the safety from the risk of public exposure to a radioactive material. According to the applicable codes and standards, the cask should maintain the structural integrity not only in normal condition but in hypothetical accident condition so that the inner material may not leak. The case of 9-m drop is significantly considered as the worst scenario among the accident conditions in structural design viewpoint. In general design, impact limiters are attached near the top and the bottom of a cask body to release the impact force by cask drop as a shock absorber. The steel casing of impact limiters are filled with light and plastic or combined materials like Polyurethane foam and Balsa wood, which transfers a reduced impact load to the cask body by absorbing the kinetic energy of a cask assembly by plastic deformation of the limiters