Abstract: A casting containing toxic waste is made by centrifugally casting toxic waste in a pre-formed cage having heat conducting means therein. The casting is formed with suitable shielding materials selected as a function of the waste being cast. The finished casting contains passageways through which heat is removed. These passageways are oriented such that when two or more castings are stacked in abutment, the passageways of adjacent castings interconnect.

Abstract: A casting containing toxic waste is made by centrifugally casting toxic waste in a pre-formed cage having heat conducting means therein. The casting is formed with suitable shielding materials selected as a function of the waste being cast. The finished casting may contain passageways through which heat is removed. These passageways are oriented such that when two or more castings are stacked in abutment, the passageways of adjacent castings interconnect. Also disclosed is a method and apparatus for forming castings of polygonal exterior cross section having a contaminant barrier wall of substantially uniform thickness so that the waste storage volume of the castings is maximized and so that the castings may be stacked and stored in honeycomb fashion in a respository to minimize dead storage space.