DETERMINATION OF OXYGEN-TO-URANIUM RATIOS IN HYPO- AND HYPERSTOICHIOMETRIC URANIUM DIOXIDE AND TUNGSTEN-URANIUM DIOXIDE

Several methods for the determination of oxygen-touranium ratios in hypo-and hyperstoichiometric UO2 have been developed and/or evaluated, using NBS 950a (U3O8) and uranium metal as standards. These methods include (a) oxidation to [formula omitted] a nitric acid dissolution procedure, followed by oxidation to [formula omitted] an oxidation-reduction procedure, whereby the sample is first oxidized (in case the material is hypostoichiometric), then reduced to [formula omitted] (d) direct reduction with hydrogen (of hyperstoichiometric [formula omitted] and (e) hydriding, whereby the free uranium metal in hypostoichiometric UO2 is first converted to UHg and the hydrogen subsequently determined. In addition, moisture has been determined on a number of samples in order to evaluate its effect on the oxygen-to-uranium ratios obtained using the above methods. In general, the accuracies obtained are within the expected accuracies of the procedures used. Where applicable, the above methods have been applied to [formula omitted] samples, using UO2 control specimens to evaluate the accuracy of the results obtained. © 1969, American Chemical Society. All rights reserved.