Research on the preparation and sintering process of (U,Ti)O2 dispersion fuel microsphere

Abstract

This paper discusses the preparation of titanium-doped UO2 microsphere by the method of sol–gel, its microstructure, pore distribution, grain sizes, and the titanium element distribution through metallographic microscope, scanning electron microscope (SEM) and energy diffraction spectrum (EDS) as well as its density with water immersion method. The experimental results show that at a certain sintering temperature, the adding of a small amount of titanium can obviously improve the sintering performance. In the experimental conditions, the optimum amount of doped titanium is under 0.3% (mass fraction) and the sintering temperature is 1250–1350 °C. After the study on the activated sintering mechanism, it is proved that the material transfer mechanism may be the joint action of strengthening cation diffusion and residual oxygen. With regard to the titanium element distribution, in addition to the solid solution of some on the outside of UO2 microspheres, the other titanium oxides gather in the grain boundary in the form of free phase particles.