Abstract: Radioactively contaminated material is cleaned by contacting the material with a decontaminating liquid comprising an aqueous solution of nitric acid containing an NOx generating agent. The NOx generating agent may be a nitrite, for example, sodium nitrite, or a ferrous metal. The material to be cleaned may comprise a plastics material contaminated with uranium or other actinides. Cleaning is effected by placing the material in a rotatable, apertured vessel in which the material is subjected to a leaching cycle by contact with the decontaminating liquid and then a washing cycle in which the material is contacted with a washing liquid.

Abstract: Radioactively contaminated material is cleaned by placing the material in a permeable container, such as a bag, and inserting the container into an apertured, rotatable vessel. The material is then subjected within the rotating vessel to a leaching cycle, using nitric acid, and a washing cycle, using fresh water. Preferably, at least one further washing cycle is employed. After discharging the washing liquid, the material is subjected to a spin-drying operation. The material undergoing cleaning is a filter medium which includes a glass component.

Abstract: Thorium is removed from raffinate effluent by pre-washing with odorless kerosene to remove organic contaminants, followed by solvent extraction counter-currently with tri-n-octylphosphine oxide in odorless kerosene. The loaded solvent from the solvent extraction is back-washed with K.sub.2 CO.sub.3 solution at about 60.degree. C., and subsequent lime addition precipitates Th(OH).sub.4.