High-temperature studies of UO2 and ThO2 using neutron scattering techniques

Abstract

A review of the results of recent neutron diffraction, coherent diffuse and inelastic scattering experiments on UO₂ and ThO₂ at temperatures between 293 K and 2930 K is given. These provide direct evidence for thermally induced Frenkel oxygen lattice disorder at temperatures > 2000 K and give data on the lattice expansion, ionic potentials and elastic stiffness constants to 2930 K for the first time. The results are important for an understanding of the thermophysical behaviour of UO₂ and contribute to the data base of thermodynamic properties of UO₂.