Radiolytic oxidation and reduction of plutonium

It has been shown on several occasions that all other things being equal, the rate of migration of plutonium through an aquifer is greatly influenced by its oxidation state. It is a reasonable expectation that other actinides exhibiting multiple oxidation states will behave similarly. By and large, the more highly charged ions in solution move through rock strata more slowly than those of lesser charge. Thus for comparative experiments on the relative migration rates of Pu(IV) and Am(III) we would expect Pu(III) to move about 10 times faster than Pu(IV) and it has been shown PuO22+ moves about 250 times more rapidly than Pu(IV). Since one of the more important paramters of safety assessment is radionuclide migration rate it can be seen that it becomes important to know the oxidation states of radionuclides (actinides for the purpose of this report) existing in possible leachates from the material originally emplaced in a repository. It was with this in mind that a study of the intrinsic stability of plutonium oxidation states in ground water solutions was undertaken