A process for the recovery of cs 137 - salts of irradiated nuclear fuel

摘要

1,037,952. Processing nuclear fuel. GELLESCHAFT FUER KERNFORSCHUNG. May 15, 1964 [May 15, 1963; July 6, 1963], No. 20474/64. Heading G6R. A nuclear fuel is reprocessed and/or separated by a method which comprises reacting the fuel with an alkaline fused salt system containing an oxidizing agent. The fused salt may consist of an alkali metal nitrate with or without an alkali metal carbonate or hydroxide. Molybdenum may be separated from uranium, UO2, or a mixture of UO2 and PnO2 by melting with sodium nitrate or a mixture of sodium nitrate and sodium bicarbonate, cooling, and extracting the product with water or dilute caustic soda to remove molybdenum. Caesium fission product may be removed in the same way, and, if both molybdenum and caesium are present, they are separated by adding phosphoric acid and nitric acid to precipitate caesium phosphomolybdate and then separating caesium by ion exchange. Ce, Ru, Nb, and Zr fission products are removed from irradiated UO2 by melting with sodium nitrate, leaching the melt with water, and dissolving the uranium in dilute acid, leaving the fission products as a residue. Mixtures of UO2 with PnO2 or ThO2 are melted with NaNO3 and the melt washed with water and dissolved in dilute HNO3; the uranium dissolves leaving a residue containing the Pn or Th. NaNO2 may be used in place of NaNO3 to form the melt with the UO2-PnO2 mixture. As the oxidizing agent, reference is made also to peroxides, chlorates, and perchlorates.