Rate Controlling Factors in the Carbothermic Synthesis of Advanced Fuels

Considerable effort has been expended to synthesize the carbides, nitrides, and carbonitrides, of uranium, Plutonium, and their solid solutions by the carbothermic reduction of oxide-carbon mixtures. Experimental results reported in the literature for the U-C-O-N system indicate that one of two limiting mechanisms controls the rate of the conversion reaction: These mechanisms are solid-state diffusion within the individual reactantproduct particles, and removal of CO from the entire reacting system. This reported information is used to analyze the use of a fluidized bed for carbothermic conversion in the vicinity of 1500°C in the U-C-O-N system and to approximate the rate of conversion in the U-Pu-C-O-N system.