Thermal expansion of ThO2-2, 4 and 6 wt.% UO2 by HT-XRD

The lattice thermal expansion (quasi-isotropic) behaviour of polycrystalline sample of ThO2-2, 4 and 6 wt.% UO2 has been investigated from room temperature to 1623 K in vacuum using high-temperature X-ray diffraction (XRD). The incorporation of UO2 systematically influences the thermal expansion behaviour of ThO2. The coefficients of quasi-isotropic average lattice thermal expansion of ThO2, ThO2-2, 4 and 6 wt.% UO2, over a temperature range of 293 and 1623 K, are found to be as 9.67×10−6, 9.82×10−6, 10.09×10−6 and 10.37×10−6 K−1, respectively. This study will be useful in designing the nuclear reactor fuel assembly based on ThO2.