PULSE-RADIOLYSIS STUDY OF THE REACTION-KINETICS OF H-ATOMS WITH ACTINIDES IN ACIDIC AQUEOUS-SOLUTIONS

Rate constants k for reactions of H atoms with Pu(VI), Pu(IV), Pu(III), Np(IV), Np(III), U(VI), and U(IV) in HClO4 and H2SO4 are studied using the competing reaction of H atoms with benzoic acid, methylene blue, or IrCl6(2-). A dependence is found in the series U(VI), Np(VI), and Pu(VI) between k and E0(VI)/(V). The rate constants are an order of magnitude smaller in HClO4.