Thermal expansion of neptunium-uranium mixed oxides

Abstract

Thermal expansions of Np y U{1−y}O 2 solid solutions were investigated between room temperature and 1273 K by a high temperature X-ray diffraction technique. The lattice parameters of Np yU 1−yO 2 solid solutions at high temperatures were given in polynomial expressions of temperature. High temperature heat capacities, C p of Np y U 1−yO 2 solid solutions were estimated from the thermodynamic relation using the measured thermal expansions and literature data. The estimated errors in the calculated C p of UO 2 were less than ±5%.