MUTUAL IMPACT ASSESSMENT ON TRANSPORT AND STORAGE OF DUAL PURPOSE METAL CASK

Spent fuel was assumed to be stored at away from reactor by dual purpose metal casks. These casks will be transported from nuclear power plants to a storage facility. After several tens of years these casks will be transported to a reprocessing plant. Under this scenario, mutual impact assessment of transport and storage of the cask were carried out. From nuclear power station to storage facility, casks with metal gaskets in the lids will receive mechanical vibration in transport. Influence of the mechanical vibration in transport on the metal gasket was experimentally investigated on the containment performance in storage. As the results, we found that required containment performance in storage was secured. During a long-term storage, the metal gasket will be subjected to a high temperature due to decay heat of spent fuel. This will cause creep deformation and corresponding relaxation of the gasket. The containment performance of the metal gasket was analyzed by a finite element method code (ABAQUS). As the results, we found that the required containment performance of the gaskets in transport was secured. For post-storage transportation, the integrity of the spent fuel in the metal casks should have been confirmed firstly at the time of installation into the metal casks. The spent fuel should have been properly installed in the metal casks and transported from the power plants to the storage facility. In the storage facility, there should have been no abnormality for the pressure between the cask lids, for the cask surface temperature, and no external force acted on the casks. Based on these conditions, we could evaluate that the metal casks can be safely transported after storage without opening the cask lids for visual inspection.