Estimation of the heat capacity of some uranium-rare earth mixed oxides from thermal expansion and vice versa

Abstract

Estimation of the high temperature heat capacity (C p) data from experimental high temperature thermal expansion (α v) data and vice versa from the known values of the ratio (αv/C p) at low temperatures were carried out by assuming linear relationship of the ratio α v /C p with temperature (at T > θ D). The assumption was examined using the known α v and C p values of single phase fluorite systems such as UO2, ThO2 and PuO2. It was also examined using the known α v and C p of the mixed oxides (U1−y Lay) O2±x (y = 0.2, 0.4, 0.6 and 0.8). The estimated values of α v and C p are in good agreement with the experimental values within ±3%. Using the assumption the high temperature heat capacity data of (U1−y Ce y ) O2 (y = 0.2, 0.8) and (U1−y Gd y ) O2±x (y = 0.2, 0.5) were computed from the experimental high temperature α v data.