Thermodynamic modelling of advanced oxide and carbide nuclear fuels: Description of the U–Pu–O–C systems

In the present work a thermodynamic model is derived for the (U, Pu)O2 oxide, the (U, Pu)C carbide fuels using the Calphad method to describe consistently both phase diagrams and thermodynamic data of the phases involved in the U–Pu–O–C system. All the available thermodynamic and phase diagram data of the binary and ternary sub-systems are very well reproduced by our model. For the quaternary system, the calculated phase equilibria in the U0.3Pu0.7–C–O region are in good agreement with the experimental data.