The Conversion of Uranium Hexafluoride to Uranium Dioxide

Four different methods for the conversion of UF₆ to ceramic grade UO₂ powder have been developed to an industrial scale. Two of them, the ADU and AUC processes, are based upon precipitation of uranium compounds from aqueous solutions. The other two follow a dry route in which UF₆ is decomposed and reduced by steam and hydrogen in either fluidized beds or rotating kilns. The quality requirements for the conversion products, UO₂ powder, are closely related to the quality of the sintered pellets. An important requirement is the influence of the conversion process and its process parameters on sintered density. The aqueous AUC process is attractive, particularly if UNH is also to be processed. The dry processes are, however, expected to become of increasing importance. Rotating kilns have some favorable features as compared to fluidized beds.