Calorimetric studies on urania–thoria solid solutions

Abstract

The enthalpy increments of (UyTh1−y)O2 solid solutions with y=0.1, 0.5 and 0.9 were measured by using a drop calorimeter of isoperibol type. The experimental data cover the temperature range 473–973 K relative to 298 K. Other thermodynamic functions such as heat capacity, entropy and free energy function of these solid solutions were derived from the measured enthalpy increment values. The results indicate that the enthalpies of (UyTh1−y)O2 solid solutions in the temperature range 473–973 K obey the Neumann–Kopp molar additivity rule.