Sol-gel microsphere pelletization: A powder-free advanced process for fabrication of ceramic nuclear fuel pellets

Abstract

Hydrated gel-microspheres of U, Pu, Th oxide or oxide plus carbon mixture of diameter 400-800 μ were prepared by ammonia gelation processes. They were dried and subjected to suitable treatment for obtaining free-flowing oxide, carbide or nitride micro-spheres of diameter 200-400 μ suitable for direct pelletization and sintering. The oxide, carbide and nitride pellets were, in general, sintered at high temperature in Ar+8% H2. However, for UO2 and (U, Pu)O2 pellets low temperature (1200 °C), short duration (1 h) oxidative (CO2 or N2+air) sintering (LTS) was also successful, thereby reducing electrical energy and gas consumption during sintering. Thus, the combined SGMP-LTS process simultaneously minimized "radiotoxic dust hazard" and fuel fabrication cost in case of UO2 and (U, Pu) O2 pellets. © 1993 Indian Academy of Sciences.