Development of transportation and storage cask holder with high seismic resistant

The needs for interim storage of spent fuels have been growing rapidly in Japan because of closing full of spent fuel storage pods in nuclear power plants. Due to limited space in nuclear power plants in Japan, most feasible option may be dry storage system by using transportation and storage casks installed in interim storage facilities. Mitsubishi Heavy Industries, Ltd., developed a cask holder which holds the bottom of casks with satisfaction of seismic resistant of the cask without any modification of the cask against further increase of required seismic force from current regulation during the long storage period. The cask is placed on the cask holder without any fixing connection. The cask holder strains horizontal displacement and inclination of the cask during a strong earthquake. This paper shows the design and function of the storage cask holder. It also shows a seismic evaluation method established on the basis of the shaking test results with scale model of the cask and the holder.