Process for producing uranium oxide rich compositions from uranium hexafluoride

A method of converting uranium hexafluoride to a uranium dioxide rich powder in the form of dendritic particles by a continuous flame reaction comprising the steps of:

• (a) introducing an oxygen-containing gas into a reaction zone initially heated to a temperature of at least about 100.degree. C and maintained under a vacuum of about 1 to about 25 inches of mercury,
• (b) operating an ignition means in said reaction zone,
• (c) introducing a shielding gas into the reaction zone,
• (d) introducing a reducing carrier gas so that it is surrounded by the shielding gas upon entering the reaction zone,
• (e) introducing a flow of uranium hexafluoride so that it is mixed with the reducing gas, said mixture being maintained at a temperature of less than about 550.degree. C prior to introduction into the reaction zone in order to avoid any reaction between the uranium hexafluoride and the reducing gas prior to introduction of said mixture to the reaction zone, and said mixture being surrounded by the shielding gas upon entering the reaction zone giving a reaction flame maintained out of contact with any solid structural surface defining said reaction zone, and
• (f) collecting the uranium dioxide rich powder produced in the reaction zone.

A method of converting uranium hexafluoride to a uranium dioxide rich powder in the form of dendritic particles by a continuous flame reaction comprising the steps of:

• (a) introducing a reducing carrier gas into a reaction zone initially heated to a temperature of at least about 100.degree. C and maintained under a vacuum of about 1 to about 25 inches of mercury,
• (b) operating an ignition means in said reaction zone,
• (c) introducing a shielding gas into the reaction zone so that the shielding gas surrounds the reducing gas upon entering the reaction zone,
• (d) introducing an oxygen-containing gas into the reaction zone,
• (e) introducing a flow of uranium hexafluoride so that it is mixed with the reducing gas, said mixture being maintained at a temperature of less than about 550.degree. C prior to introduction into the reaction zone in order to avoid any reaction between the uranium hexafluoride and the reducing gas prior to introduction of said mixture of the reaction zone and said mixture being surrounded by the shielding gas upon entering the reaction zone giving a reaction flame removed from contact with any solid structural surface defining said reaction zone, and
• (f) collecting the uranium dioxide rich powder produced in the reaction zone.

A method of preparing a uranium oxide rich composition in the form of dendritic particles from uranium hexafluoride in a reaction zone in the presence of an active flame having the steps of:

• (a) introducing a first gaseous reactant comprising a mixture of uranium hexafluoride and a reducing carrier gas into the reaction zone, said reactant being maintained at a temperature of less than about 550.degree. C prior to introduction into the reaction zone in order to avoid any reaction between the uranium hexafluoride and the reducing gas prior to introduction of said first reactant to the reaction zone,
• (b) separately introducing a second gaseous reactant comprising an oxygen-containing gas into the reaction zone,
• (c) separately introducing a shielding gas into the reaction zone between said first gaseous reactant and said second gaseous reactant which temporarily prevents substantial mixing and reaction between said first and second gaseous reactants to produce a uranium dioxide rich composition until sufficient cross diffusion of said reactants and the shielding gas occurs as said reactants and the shielding gas pass through the reaction zone resulting in conversion of the uranium hexafluoride to a particulate uranium dioxide rich composition in the presence of residual reducing gas and gaseous reaction products, and
• (d) introducing a third gaseous reactant comprising an oxygen-containing gas into contact with the particulate uranium dioxide rich composition, the residual reducing gas and the gaseous reaction products thereby converting the residual reducing gas in the reaction zone to an oxidized form and oxidizing the uranium dioxide rich composition to a higher oxide of uranium.