Radiation-chemical oxidation of neptunium(6) ions in alkaline aqueous solutions in the presence of peroxidisulfate-, periodate- and hypobromite-ions

In an aerated NaOH solution containing acceptors of hydrated electrons, S2O82-, H3IO62- or BrO-, neptunium(6), when affected by γ-radiation, transfers to the septavalent state. At a dose of 2x1016 eV/mlxs in case of S2O82- the Np(7) output increases from 2 to 4.5 ions/100 eV as NaOH concentration grows from 0.1 to 2M. In presence of BrO- neptunium(7) output varies from 5.3 to 7.0 ions/100 eV as the NaOH solution changes from 1 to 3 M. In H3IO62--containing solutions the greatest Np(7) output of 4 ions/100 eV is achieved in 0.5 M NaOH solution. The mechanism of radiation-assissted oxidation of neptunium(6) ions in presence of S2O82-, H3IO62- or BrO- has been discussed