Controlled PuO sub 2 Particle Size from Pu(III) Oxalate Precipitation

摘要

PuO sub 2 with reproducible particle size and morphology can be produced by controlling precipitation variables affecting the initial supersaturation and final solubility of plutonium oxalate. Such feed powders with constant characteristics are essential for reproducible fabrication response and controlled microstructures in the manufacture of exp 238 PuO sub 2 heat sources. Calcination does not change the morphology or shape of the size distribution of the PuO sub 2 particles from that of the precipitated Pu(III) hydrated oxalate. For a given precipitation method, the size and morphology of the Pu(III) oxalate are determined by precipitation temperature, nitric acid concentration, plutonium concentration, and oxalate ion concentration. Functional relationships of these variables were developed to control and predetermine the size, extent of agglomeration, and dimensions of the PuO sub 2 particles over the range of these variables for PuO sub 2 production. This report describes statistically designed factorial experiments and characterization of PuO sub 2 by Coulter counter and scanning electron microscopy (SEM). These control factors were applied successfully in full-scale production. (ERA citation 10:007138)