Effect of TiO2 and Al(OH)3 on sintering behavior of UO2-Gd2O3 Fuel Pellets

The sintering behavior of UO2-Gd2O3 fuel pellets under H2 gas has been investigated using dilatometry and XRD methods. The addition of TiO2 or Al(OH)3 increased the density and grain size. A density of 95% TD and a grain size larger than 6μm are achieved by the addition of 0.1 wt% TiO2 or Al(OH)3. It was found that the densification of UO2-Gd2O3 pellets was suppressed in the temperature range of 1300 to 1500 degree C, compared to U)2 pellets. The formation of a (U,Gd)O2 solid solution is the main reason for the suppression of densification. The role of TiO2 in densification and grain growth is discussed on the basis of the densification curve and ceramography. (author)