Patent ID: 7731870

Claim:
A method for reprocessing a spent nuclear fuel, which successively comprises: a) separating uranium, plutonium and other actinides from fission products present in an aqueous nitric solution obtained by dissolving the fuel in nitric acid, said separation comprising co-extracting uranium(VI), plutonium(IV) and other actinides(IV) or (VI) from said aqueous solution by using a water-immiscible solvent phase comprising at least one extractant in an organic diluent, and then scrubbing the solvent phase with an aqueous nitric solution; b) back-extracting plutonium in the oxidation state (III) from the solvent phase resulting from step a) by using an aqueous nitric solution which contains a reducing agent capable of reducing plutonium(IV) into plutonium(III); c) back-extracting uranium(VI) from the solvent phase resulting from step b) by using an aqueous nitric solution; d) concentrating the aqueous nitric solution resulting from step c) with respect to uranium(VI); and in which a part of the uranium(VI)-concentrated aqueous solution resulting from step d) is used for further back-extracting during step b) at least one actinide(IV) selected from neptunium(IV) and thorium(IV) from the solvent phase resulting from step a).