Preparation of（Th,U）O₂ Microspheres by Sol-gel Process

(Th,U)O₂ microspheres were prepared by sol-gel process through hexamethylenetetramine（HMTA）-urea system.Gelling temperature,washing and calcination route were studied under different Th/（Th+U）.Microspheres were sintered at different temperature and the microstructure were studied by met-alloscope（MS） and scanning electron microscope（SEM）.The results showed that the internal gelation method could be applied well in preparing（Th,U）O₂ microspheres with the Th/（Th+U） ratio no higher than 0.5;compacted（Th,U）O₂ microspheres were gained at sintering temperature between 1200℃and 1500℃,and the density could reach 99% of TD.The SEM results showed that ThO₂ and UO₂ had formed well-proportioned solid solution with pores tiny and homogeneous distribution.