WASTE NUCLEAR FUEL PROCESSING METHOD Russian patent published in 2015 - IPC G21F9/28 

FIELD: power industry.

SUBSTANCE: in the offered method the tablets of oxidic spent nuclear fuel destroyed at cutting of fuel elements are dissolved with heating in water solution of iron nitrate (III) at the molar ration of iron to uranium in the fuel 1.5-2.0:1, the formed deposit of the hydroxy iron salt with undissolved nuclear fuel fission products are separated by filtering, and from the obtained subacidic solution the uranyl peroxide is precipitated by consecutive adding to the solution with mixing of disodium salt of ethylene diamine tetraacetic acid. Then the obtained heterogeneous system is held at least 30 minutes and after separation washing with acid and water the uranyl peroxide deposit of peroxide is subjected to solid-phase recovery at heating by processing by its alkaline solution of a hydrazine hydrate in water at double-triple molar excess of hydrazine with reference to uranium, with subsequent separation of obtained hydrated uranium dioxide UO₂·2H₂O, its washing by HNO₃ solution with the concentration 0,1 mol/l, water and drying. While the deposit of the hydroxy iron salts with fission products, mother solution of the stage of sedimentation of peroxides from residue of fission products, waste of alkaline and washing solutions are supplied to the waste collector for their subsequent processing.

EFFECT: improvement of environmental safety and decrease of waste amount.

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