Properties, blending and homogenization of (U,Th)O2-UO2 powder

(U,Th)O2 mixed-oxide powder was prepared by coprecipitation from mixed-nitrate solutions using NH4OH, and the physical properties of material calcined at different temperatures obtained. Properties measured included particle morphology and size distribution, surface area, O/M ratio and bulk and tap density. Blending of calcined powder at a 6 wt% level with UO2 was studied for different time periods and the distribution of Th particles in the powder and in sintered pellets evaluated statistically; little increase in homogeneity was observed after about 1 hour. The sintered-pellet densities were not influenced by the mixed-oxide addition, which appeared to act as an inert diluent. (Auth.)