On the present state of investigation of thermodynamic properties of solid and liquid UO2+x

A critical assessment of two review articles by Baichi et al, which was published dealing with the thermodynamic properties of uranium dioxide at high temperatures is presented. The focus of the assessment encompass the heat capacity of solid UO2 at high temperatures, the solidus-liquidus boundaries of UO2±x, and the heat capacity of liquid UO2. The laser-flash method used to determine the high temperature heat capacity of solid UO2 provides consistent results, while laser experiments provide reliable information on the dependence on temperature of the heat capacity of liquid UO2 in flexible temperature ranges. The rejection of solidus-liquidus data for UO2±x obtained by a laser heating technique is also misinterpreted.