Redox reactions of neptunium and plutonium in alkaline aqueous solutions upon gamma radiolysis

The paper is a brief review of data obtained by the authors from the study on redox reactions of neptunium and plutonium ions upon gamma-radiolysis of their aerated alkaline aqueous solutions. It includes the information on r adiolytic reduction of Np(V), Np(VI), and Pu(VI) ions under Various experim ental conditions. It was found that the values of Np(VI) and Pu(VI) reducti on yields do not depend on alkali concentration. The values considerably in crease in the presence of some organic compounds (EDTA and formate were inv estigated). The formation of the Np(V) peroxo complex was observed in the g amma-radiolysis of alkaline aqueous solutions of Np(VI) and Np(V) in the pr esence of nitrate. The mechanism of radiolytic redox reactions of the ions is discussed in some detail. (C) 1999 Elsevier Science Ltd. All rights rese rved.