Abstract: There are needed for containers for the transportation and/or for the storage of spent fuel elements inner linings which guarantee a good heat contact to the outer container and have little operating expense. This is attained by placing in the outer container a bottom and a flange, then positioning therebetween and welding thereto a jacket provided with an axial slot and thereby a flexible diameter. The slot is then subsequently likewise covered and welded.

Abstract: An improved container for transportation or storage of radioactive substances, especially spent nuclear fuel elements, has a cylindrical open-top thick-wall metallic body for shielding gamma radiation. A liner for the container has a top peripheral flange engaged with the bottom of a counterbore in the container open top. A thick gamma-ray shielding cover for the lining is disposed in the counterbore and screw means detachably secure both the lining flange and the cover to the body independently. The body has exterior generally parallel spaced cooling fins transversely intersected by flanges of lesser height to minimize fin cracks extending into the body. Neutron shielding is disposed in the exterior spaces between the fins and the flanges.