UF6 conversion of uranyl nitrate from spent fuel reprocessing

The new COMURHEX process at Pierrelatte for the conversion of uranyl nitrate to UF6 from the slightly enriched uranium in the spent fuel from light water reactors is described. The uranium is precipitated as ammonium diuranate which is calcined and reduced to UO2 in a special rotary kiln. UO2 is hydrofluorinated in a moving bed reactor, and the UF4 converted to UF6 by direct reaction with fluorine gas in a flame reactor. Purification is by a series of complimentary operations based on the differing volatilities and chemical properties of the contaminant fluorides. Nonvolatile contaminant fluorides are removed by filtration which eliminates β and γ contaminants, the α being removed by means of a sorption tower. The facility is preparing to operate at the rate of output required for 1976. (U.K.)