Radiolytic oxidation of americium(III) to americium(V) and plutonium(IV) to plutonium(VI) in saline solution

Abstract

The redox behaviour of americium and plutonium in concentrated NaCl solutions (more than 1 M NaCl) under the influence of their own alpha radiation is investigated. The α radiation (greater than 0.5 Ci l −1) induces the oxidation of the Cl − ion and hence creates a strongly oxidizing medium in which americium(III) and plutonium(IV) present initially become oxidized to americium(V) and plutonium(VI) respectively. The oxidation kinetics depend on the α-radiation dose, NaCl concentration and pH of the solution. Americium(V) remains stable at pH > 8 and plutonium(VI) in a wide range of pH.