Preparation of UN microspheres by external gelation

Abstract

Uranium mono-nitride (UN) microspheres are expected to play an important role in various miniaturization module reactors. The combination of UN core and tri-structural-isotropic (TRISO) coatings will bring improved efficiency and safety. Carbon-containing gel microspheres were prepared by external gelation, followed by carbothermal reduction and nitridation to synthesize UN. The effects of C/U molar ratios and heat-treatment schemes on the composition and microstructures of UN microspheres were studied. The results indicated that the external gelation could be used to prepare UN microspheres, with the highest UN content of 93 wt%.