B.R. Ambekar

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

Abstract Earlier it was shown that ThO 2 and CeO 2 form almost an ideal solid solution throughout the homogeneity range. In this manuscript, we report the lattice thermal expansion behaviour of Th 1− x Ce x O 2 (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 ( α a ) progressively increases on going from ThO 2 to CeO 2 in Th 1− x Ce x O 2 . The typical α a values of ThO 2 , Th 0.5 Ce 0.5 O 2 and CeO 2 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 Ce 4+ at Th 4+ sites in ThO 2 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.

Bulk thermal expansion studies of Th1−xCexO2 in the complete solid solution range

Abstract ThO2 and CeO2 are shown to form an almost ideal solid solution throughout the homogeneity range. Bulk thermal expansion studies on Th1−xCexO2 (0.0⩽x⩽1.0) were carried out by dilatometry from 293 to 1123 K in air. The average linear thermal expansion coefficients, α , of ThO2 and CeO2 were found to be 9.04×10−6 and 11.58×10 −6 K −1 , respectively, between 293 and 1123 K. The substitution of Ce4+ at Th4+ sites in ThO2 induced a systematic upward trend in the thermal expansion behavior throughout this series of solid solution on going from ThO2 to CeO2.