Patent Number: 050645757
Section: summary

The invention concerns a double container for the storage of radioactive material having an improved, seal. From Swiss LP 650,354, a container combination is known for the transport and storage of fuel elements which consists of a removable inner container and an outer container, in which each of the containers has its own cover. The loading of the inner container takes place, as is known, in a hot cell. But the final sealing with the cover must also take place in the hot cell, which can only be accomplished with a considerable outlay, since the cover must be welded to the container. Even if the welding of the cover and container already offers good security, there is a need for a further increase in the security of the containment of the radioactive material. The object of the present invention is to provide a seal of the type which can be easily effected and make the containment of the radioactive materials even more secure. The object is achieved by sealing the radioactive material in a container within the hot cell and subsequently welding an outer cover on the container outside the hot cell. Advantages and practical further developments of these solutions for sealing a double container system are described in detail in this specification. In accordance with the present invention, an additional outer cover in the form of a sealing plug is provided for the inner container of the double container system. The welding of this outer cover after the inner cover has been screwed into the loaded inner container in a shielded region (hot cell), or, in the case of the double container system, locked within the cell aperture of the hot cell, takes place outside of this shielded region since the screw-type cover takes care of the required shielding of the radioactivity. Screwing the inner cover into the container inside the hot cell, or in the case of the double container system which is locked in the hot cell, requires only a comparatively low outlay. Welding outside of the shielded region (outside of a hot cell) reduces the outlay for the welding process and for the devices required considerably. By means of the additional outer cover, the containment of the radioactive materials is more secure. When we refer to radioactive material, it is understood that in the condition considered here it is enclosed in its own sheath (box, metal mould) and thus is loaded into the inner container with its sheath. All processes for loading and sealing take place on the inner container which is inserted in the shielding container. It is particularly advantageous that the welding of the outer cover to the inner container be carried out with the inner container already inserted in the shielding container.