Air-cooled krypton-85 storage facility with natural convection

In the Federal Republic of Germany's 'Entsorgungskonzept' krypton has to be separated from the dissolver off-gas in the reprocessing plant and stored to await decay of the krypton-85. It is planned to fill krypton-85 in stainless-steel pressure cylinders. In an air-cooled storage facility the decay heat from the steel cylinders will be carried off by natural convection. Five cylinders are stacked in vertical shafts arranged in a storage rack. Ambient air enters the building through air inlet channels. It then flows through the annular space between the pressure cylinders and the storage shaft, and the heated air leaves the building via air outlet channels. The pressure cylinders in the storage rack are protected by the building against earthquakes and an aircraft crash. The dimensions of the building are 23 x 23 x 27 m, with a capacity of 800 krypton cylinders. The results of the conceptual design study of the air-cooled krypton-85 storage facility with natural convection will be presented with regard to thermal aspects, radiation exposure and barrier system, and accident conditions. Although some safety aspects need more detailed investigation, the present results show that the facility can principally be built in such a way as to meet the basic requirements for the licensing procedure. (author)