Fabrication of Monolithic UAl<sub>2</sub> Pellet for High-Density Nuclear Fuel

Abstract

Uranium powder, which can be obtained by the atomization process, was used to fabricate UAl2 by using powder metallurgy technology. Uranium powder and Al powder were blended, extruded, and annealed into a UAl2 rod in a mold. Sound UAl2 rods were fabricated by the powder metallurgical process. The relative density of the UAl2 pellet formed by an annealing was at about 94%. The density increased with higher constraints on the mold and a smaller particle size of the uranium powder. A coarse uranium powder of about 80 μm in average diameter represented the remaining un-reacted uranium phase. On the other hand, a fine uranium powder of about 50 μm in average diameter could achieve a pure UAl2 phase without a uranium phase. The analysis by an X-ray diffraction pattern confirmed that the annealed specimens had interacted to form a UAl2 phase. Conclusively, the sintered UAl2 pellet is expected to be useful in developing advanced fuels.