Experiments conducted in a 2 1/2-inch diameter reactor have demonstrated that the continuous fluorination of uranium tetrafluoride to hexafluoride with elemental fluorine in a fluidized bed is possible. Practicable fluorine efficiencies and conversion rates were attained with good temperature control in experiments with refined uranium tetrafluoride. Runs made with crude uranium tetrafluoride, derived from the reduction and hydro-fluorination of ore concentrates produced by the acid-leach process, indicated that these also can be processed at satisfactory rates and efficiencies. Uranium tetrafluoride derived from carbonate-leached ore concentrate gave a lower production rate and was more difficult to process because of sintering tendencies.

A one-step, continuous, fluid-bed process for the conversion of uranium hexafluoride to uranium dioxide was successfully carried out in preliminary experiments in a 1 1/2-inch-diameter Monel reactor. Hydrogen and steam were used for simultaneous reduction and pyrohydrolysis reactions carried out at 600 deg C, resulting in the formation of a dense coating of dioxide on the starting bed of uranium dioxide. The effects of uranium hexafluoride feed rate and reactant excesses on conversion were investigated. Results of fluid-bed steam pyrohydrolysis runs on uranium tetrafluoride are also presented.

A new, dry process for the production of uranium dioxide powder from uranium hexafluoride by fluidization and particle-coating techniques was developed. The process involves direct conversion of uranium hexafluoride to a solid, UO2F2, by hydrolysis with steam and the reduction of the UO2F2 to the dioxide by reaction with was carried out in 3-in.-diameter Monel reactors.

A one-step, continuous, fluid-bed process for the conversion of uranium hexafluoride to uranium dioxide was successfully carried out in preliminary experiments in a 1 1/2-inch-diameter Monel reactor. Hydrogen and steam were used for simultaneous reduction and pyrohydrolysis reactions carried out at 600 deg C, resulting in the formation of a dense coating of dioxide on the starting bed of uranium dioxide. The effects of uranium hexafluoride feed rate and reactant excesses on conversion were investigated. Results of fluid-bed steam pyrohydrolysis runs on uranium tetrafluoride are also presented. (auth).

A fluid-bed process for the preparation of dense, spheroidal uranium dioxide particles directly from uranium hexafluoride for dispersion and compacted fuel element applications has been developed. In the process, a uranium hexafluoride is reacted with mixtures of steam and hydrogen in a bed of uranium dioxide fluidized by the reactant gases and maintained at 650 to 700 degrees C. The solid reaction products deposit as a dense layer on the surface of the bed particles. The operating procedure involves alternating periods of uranium hexafluoride feed periods of fluoride cleanup when only steam and hydrogen are fed. Product is withdrawn at the end of each cleanup period.