HANDLING METHOD OF DEPOSITS BASED ON MOLYBDENUM AT PROCESSING OF SPENT NUCLEAR FUEL OF NPP Russian patent published in 2012 - IPC G21F9/28 

FIELD: power industry.

SUBSTANCE: invention refers to processing technology of spent nuclear fuel of nuclear power plants (NPP SNF). Handling method of deposits based on molybdenum at processing of NPP SNF provides for liberation of molybdenum in the form of nonstoichiometric zirconium molybdate at heating of initial nitrogen acid solution, differs by the fact that the deposit which has been precipitated or settled at heating of temperature of 95-130°C of initial solution containing 100-900 g/l U and 1.0-3.5 mol/l HNO₃, is separated from it and treated with solution of decomposable complexing agent, which is then adecomposed; after that, molybdenum is deposited for the second time at increased temperature and controlled acidity of solution by introducing salt-nonforming oxidation-reduction reagent, and mother solution is returned to the process. As complexing agents of molybdenum there used are ligands capable of self-decomposition without any residue nitrogen acid solutions, and namely hydric dioxide or carbonates of monovalent cations. As reducing agent there used is hydrazine nitrate or U (IV) in presence of hydrazine, and as oxidiser there used are nitrogen oxides or small quantities of Mn (VII) or Cr (VI).

EFFECT: invention allows avoiding losses of plutonium with deposits of zirconium molybdate.

7 cl, 4 ex