Thermal expansion of ThO2-2 wt% UO2 by HT-XRD

The linear thermal expansion of polycrystalline ThO2-2 wt% UO2 has been inv estigated from room temperature to 1473 K in flowing helium atmosphere usin g high temperature X-ray diffractometry. ThO2-2 wt% UO2 shows a marginally higher linear thermal expansion as compared to pure ThO2. The average linea r and volume thermal expansion coefficients of ThO2-2 wt% UO2 are found to be <(alpha)over bar>(a) = 9.74 x 10(-6) K-1 and <(alpha)over bar>(v) = 29.5 2 x 10(-6) K-1 (298-1473 K). This study will be useful in designing the nuc lear reactor fuel assembly based on ThO2, (C) 2000 Published by Elsevier Sc ience B.V. All rights reserved.