DEVELOPMENT OF SOLVENT EXTRACTION PROCESSES FOR THE H.T.G.C.R. FUEL CYCLE. PART 3. CHEMICAL DATA FOR THE EXTRACTION OF ACTINIDES AND FISSION PRODUCTS FROM AQUEOUS BERYLLIUM SULPHATE SOLUTIONS USING AMINES.

Chemical data are presented for the actinides (uranium, plutonium and thorium), the fission products (cerium, zirconium, niobium and ruthenium) and beryllium in the extraction of these from beryllium sulphate solutions by amines, in particular Primene-JMT and Alamine-336. The data so obtained define the major chemical parameters requiring control in a solvent extraction process to decontaminate beryllium sulphate, and indicate that the use of the solvent Primene-JMT/Solvesso-100 will adequately remove the uranium, thorium, plutonium, cerium, zirconium and niobium without extracting significant quantities of beryllium. Ruthenium is not highly extractable and strontium and caesium are extractable only in trace quantity. Although this process will be adequate for primary decontamination of the beryllium sulphate, a further step to remove residual ruthenium, strontium and caesium may be required. The actinides with the extracted fission products are readily stripped from the amine phase with nitric acid, thus permitting recovery of the actinides by a conventional tributyl phosphate process. The amine phase is readily converted back to the free-base form using sodium carbonate. This is necessary to prevent recycling of the nitrate which would inhibit the extraction of thorium, plutonium and the fission products.