Thermal expansion of ThO 2–2 wt% UO 2 by HT-XRD

Abstract

The linear thermal expansion of polycrystalline ThO 2–2 wt% UO 2 has been investigated from room temperature to 1473 K in flowing helium atmosphere using high temperature X-ray diffractometry. ThO 2–2 wt% UO 2 shows a marginally higher linear thermal expansion as compared to pure ThO 2. The average linear and volume thermal expansion coefficients of ThO 2–2 wt% UO 2 are found to be α ̄ a =9.74×10 −6 K −1 and α ̄ v =29.52×10 −6 K −1 (298–1473 K). This study will be useful in designing the nuclear reactor fuel assembly based on ThO 2.