Patent Number: 039705170
Section: description

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT The drawing is a schematic representation of a container-arrangement as applied to the process in accordance with this invention. The container arrangement comprises a first container 1, containing a granulated or pulverous radio-active material 2, which has been pre-compacted, in a so-called hot-cell (a space protected against radio-activity, whereby the radio-active material can be handled from outside). At the same time the entire container arrangement and the charge thereof are exposed to mechanical vibrations for a given period of time, thereby already effecting a filling density of 50 - 60 per cent of the pulverous or granulated radio-active material. Such density can most certainly be obtained where the radio-active mass consists essentially of chemical compounds in the form of spherical granules. In this protected space of the hot-cell the container 1 made of a thin metal or plastic such as P.V.C., is closed within a porous cover 3, which then is welded according to the process described in said co-pending applications, preferably applying an electron-beam-welding apparatus comprising a vacuum chamber, wherein the welding of the porous cover 3 to the container-wall 4 can be effected. During this process a uniform welding bead 5 is formed between the cover 3 and the wall 4 in a short time while evacuating the container. Finally a pressure of 10.sup..sup.-1 torr or less is established in the container. The construction of the container 1 differs from the container disclosed in said co-pending application in that filling, pre-compacting, welding and simultaneous evacuation of the container of the present application are carried out in a space, protected against radio-activity, i.e. a hot cell. Thus, by closing the container 1, a body is produced filled with radio-active material within a hot-cell, a fact which is important for reasons of safety, etc. Next the container 1 is placed, within the aforementioned hot-cell into a second container 6, which is made of a compressible material as well, and filled with a pressure-transmitting medium, e.g. a liquid metal 7. In space the container 6 will be closed by a cover 8 under the same conditions as the container 1, closing being effected by at 9 the cover 8 to the container wall 6, by means of an electron-beam-welding apparatus. To center the container 1 in container 6, easily deformable supporting means 10 and 11 are applied. The container-arrangement 1,6, schematically represented in the drawing, is then compacted in a hydraulic press, the containers being exposed simultaneously to a high pressure and high temperature (hot-compacting process) for a given period of time. During compacting the second container functions as a safety-buffer-element, thereby preventing the leakage of radio-active material in the course of the hot-compacting process. Should there be leakage, for example, in container 6, i.e., leakage through the container 6 wall, compacting could take place only to a limited extend or not at all, since even a slight pressure-increase is followed by a pressure equalization between the container 6 and the pressure-room of the machine. Upon leakage of the container 1 that contains the radio-active material, liquid metal will seep through the leak into the container 1 during compacting. In this case the final product (the container arrangement or assembly 1,6) will not be compacted, because the pressure-transmitting medium, e.g. liquid metal 7, penetrated the container 1, thereby equalizing pressure. After-compacting, the compacted radio-active material can be used as an isotopic heat-source by removing the container 1 from the container 6, whereafter the compacted container 1 can easily be handled as an isotopic heat-bar.