Study of some saltless reducers of plutonium and neptunium

The problem of applying some saltless Pu and Np reducers in the radioactive liquid wastes is discussed. The problem is of interest for nuclear fuel reprocessing technology. Namely, peculiarities of Pu(6), Pu(4), Np(6) and Np(5) reduction by hydroxylamine, hydrazine and ascorbic acid are considered. The chemical reaction kinetics in nitric acid and oxychloride media are studied. Depending on different conditions of concentration and the type of reducer, temperature, solution acidity and presence of catalyst, rates and duration of individual reactions can differ significantly, which allows to solve different technical tasks. Orders of constant rate and thermodynamical activation parameters for all the above reactions of Pu and Np are determined. Mechanisms of the reactions are discussed. On the basis of the obtained data, a number of methods is suggested for stabilization of different ion pairs Np and Pu(Np(5)-Pu(3), Np(5)-Pu(4), Np(4)-Pu(3) and others) aimed at their separation, or joint recovering at extraction, reextraction and sorption