LOW WEIGHT CASTOR® CASK WITH HIGH CAPACITY FOR TRANSPORT AND STORAGE OF SPENT NUCLEAR FUEL

The development of storage casks is directed to accommodate a maximum number of fuel assemblies which is possible in accordance with max. cask weight. Some of the elder NPP world-wide have a limited crane capacity of approx. 70 to 80 metric tons. GNB has developed the CASTORÒ V/12 S casks for direct dry cask storage, which fulfil both the type B(U)F transport requirements and the criteria for cask storage under normal operation and accident conditions for this special weight definitions. The CASTORÒ V/12 S is designed for 12 PWR fuel assemblies of the type W. H. 14 x 14, 16 x 16 and 17 x 17 with 5 w/o U 235 enrichment, 40 to 60 GWd/MTU and a minimum cooling time of 3 to 7 years. The cylindrical cask is made of forged carbon steel. Polyethylene rods for neutron shielding are arranged in bore holes of the cask body wall. The lid system is designed as a double barrier system for storage. The two referring lids are metal sealed and bolted (version 1). In version 2 the primary lid is bolted and the secondary lid is welded. For transport, only the primary lid is necessary. In the transport configuration, wooden-made impact limiters are attached at the lid side and at the bottom side. The CASTORÒ V/12 S cask complies with the requirements of the IAEA and of the 10CFR Part 71 for type B(U)F packages, and meets the requirements of the 10CFR72 for storage casks.