Improvements made to the decontamination processes of media containing fission products contaminated in particular with ruthenium and to the methods of the ruthenium of seperation

摘要

1,174,477. Removal of fission products. COMMISSARIAT A L'ENERGIE ATOMIQUE. 30 Oct., 1967 [3 Nov., 1966], No. 49152/67. Heading G6R. [Also in Division C1] Fission products, in particular ruthenium, are removed from solution by oxidation to the heptavalent state, followed by liquid-liquid extraction with an organic solution of a quaternary ammonium salt in an inert solvent. Irradiated plutonium-aluminium alloy is treated with sodium hydroxide solution, sodium hypochlorite added as oxidizing agent, and the solution contacted with a solution of trilaurylmethyl-ammonium chloride in xylene or carbon tetrachloride. Ruthenium is recovered from the organic solution by treatment with a basic solution containing ethanol. Graphs are given showing the effect on the ruthenium partition coefficient of variations in the concentration in the aqueous phase of NaOH, NaClO, and chloride, nitrate, aluminate, and nitrite ions. Another quaternary ammonium salt which may be used is tricaprylmethylammonium chloride, and a nitrate may be used in place of a chloride; other suitable oxidizing agents are potassium periodate and sodium hypobromite. In Example I, an effluent is decontaminated by the removal of ruthenium and technetium, and in Example II pure Ru 106 is separated from a fission product solution containing also technetium. Reference is also made to the processing of plutonium targets clad with aluminium in the preparation of transuranic elements.