Simulation of lattice thermal expansion behaviour of Th1−xPuxO2 (0.0≤x≤1.0) using CeO2 as a surrogate material for PuO2

Earlier it was shown that ThO2 and CeO2 form almost an ideal solid solution throughout the homogeneity range. In this manuscript, we report the lattice thermal expansion behaviour of Th1−xCexO2 (0.0≤x≤1.0) in the temperature range from ambient to 1473 K investigated by high-temperature X-ray diffraction. The coefficient of average lattice thermal expansion (αa) progressively increases on going from ThO2 to CeO2 in Th1−xCexO2. The typical αa values of ThO2, Th0.5Ce0.5O2 and CeO2 were found to be 9.54×10−6, 10.62×10−6 and 11.58×10−6 K−1, respectively in the temperature range 293–1473 K. Thus the substitution of Ce4+ at Th4+ sites in ThO2 has a systematic influence on the thermal expansion behaviour. These results will be useful in simulating the thermal expansion behaviour of thoria–plutonia mixed oxides.