Patent Number: 050645757
Section: claims

1. In a double container system loaded with radioactive material disposed in a sheath comprising an inner container and an outer shielding container, the improvement in which said inner container has a cylindrical wall, an inner cover in the form of a plug screwed into said wall and an outer cover welded to said wall, said weld comprising a welding gap between said outer cover and said wall, said gap being of increasing width from bottom to top,  the bottom of said gap being formed by a pair of opposed peripheral flanges, one projecting from said outer cover and one projecting from said wall,  each said flange being canted to provide said gap with a bottom of V-shaped configuration,  said root layer being formed by a tungsten electrode, gas shielded arc welding process and  said added layer being formed by a submerged arc welding process. 2. The double container system of claims 1 in which said shielding container has a step-shaped annular mouth extending above said weld to provide sufficient free space between said shielding container and said inner container to accommodate a weld testing device. 3. The double container system of claim 1 in which the bottom of said outer cover has an annular recess beneath said weld and said cylindrical wall has a groove which joins said recess to provide an annular chamber beneath said weld. 4. The double container system of claim 1 in which each of said flanges is canted on the upper and lower surfaces thereof at an angle of about 45.degree..