Combustion synthesis of urania-thoria solid solutions

The feasibility of the combustion synthesis using citric acid as the fuel was studied in order to prepare a homogeneous mixture of uranium dioxide-thorium dioxide feed powder that could be cold compacted without binder or lubricant and sintered to a high density (greater than or equal to 95% theoretical density) at relatively low temperatures (greater than or equal to 1573 K). Systematic studies were carried out to optimize various process parameters such as fuel-to-oxidant mole ratio, method of heating and sintering temperature. The powders were characterized for their carbon content, specific surface area, particle size distribution and bulk density. The crystallite size of the powders was determined by the X-ray line-broadening technique. The microstructure and surface morphology of the powders were studied using scanning electron microscopy. The reactivity of the calcined powders was determined by measuring the density of the sintered compacts prepared from them. The performance of citric acid as a combustion fuel was compared with that of poly vinyl alcohol. (C) 2000 Elsevier Science B.V. All rights reserved.