Validation of gravimetry for high-accuracy analysis of uranium

Gravimetry after calcination is an assay method for determining the quantity of a given element from the mass measurement. This method, adapted for high concentration and purity uranium solution, has the advantage of not being related to a chemical standard and of having an extremely high trueness and precision. Besides, the method is simple, robust and cost-effective. The results of the analytical method validation are shown. Expanded uncertainties, assessed thanks to a reference uranium nitrate solution, are lower than 0.2%. The technique can thus be used in addition to the well-known isotopic dilution thermal-ionisation mass-spectrometry.