EXTERNAL GELATION OF THORIUM PROCESS FOR PREPARATION OF THO2 AND (TH,U)O2 FUEL KERNELS

For refabrication of high-temperature reactor fuel elements, a process for producing dense ThO//2 and (Th,U)O//2 microspheres has been developed. The process is an external gelation process and takes full advantage of the gelation features of thorium hydroxide for formation of particles. Unlike other external gelation methods, neither viscosity increase by adding other substances (e. g. , organic polymers) to the broth nor drop formation in organic liquids is employed. The method uses few process steps and only simple process equipment. A pilot plant has been constructed so that operation with one nozzle can produce 1 kg/h of (Th,U)O//2 microspheres 500 mu m in diameter.