Process for the conversion into usable condition of actinide ions contained in the solid residue of a sulfate reprocessing process for organic, actinide-containing radioactive solid waste

摘要

A process for the conversion into a usable condition of actinide ions contained in the solid residue of a sulfate reprocessing process for organic actinide-containing radioactive solid waste, which are present in the form of water soluble sulfato complexes. The residue is absorbed with water of 1 to 2 molar nitric acid so that the residue or the largest amount of residue goes in the solution. The resulting solution is separated from the insoluble constituents of the residue in case of any insoluble residue, and heated to a temperature in the range of 40 DEG C. below the boiling point of the solution to form a hot solution. To the hot solution is added an aqueous barium nitrate solution having an amount of barium nitrate which corresponds to a small excess of barium ions over the amount required stoichiometrically for complete precipitation of the sulfate ions. The resulting reaction solution is held at a selected temperature in the same range as above for a period in the range of 0.5 to 2 hours. The reaction solution is subsequently cooled to room temperature and then is separated from the barium sulfate precipitate to form a sulfate free actinide-nitrate solution. The sulfate free actinide-nitrate solution obtained after the separation is fed to an extractive reprocessing process of exposed nuclear fuel-and/or fertile materials, the aqueous phases of which are nitric acidic.