Spent fuel shipping and storage system for Atucha Nuclear Power Station

Argentina's Atucha Nuclear Power Station is on the HWR type with pressure vessel. Its natural UO2-zircaloy fuel assemblies are bundles of 36 fuel rods, 620 cm in length and 11 cm in diameter. The fuel elements are irradiated up to 7000 MWD/MTU and stored in a conventional decaying pool adjacent to the reactor building. A project was developed to design and build a shipping cask and a dry storage place for interim storage of spent Atucha's fuel. This paper describes the cask and storage design, as well as the special container (basket) for the fuel elements. The operation of the whole system is described, with emphasis on safety aspects, and a brief reference is made to heat transfer, corrosion and costs. Safety analysis shows that even in accident conditions the radiation dose on workers in the area will be under the maximum allowed levels. Cask and storage design allows for refrigeration by air convection without surpassing a temperature of 2500C in the hottest fuel rod. Estimate unit costs for the storage system are under 0.1 mills/kWh