Phase relation assessment for O–Pu–U ternary system

The thermodynamic modelling has been performed for the O–Pu–U ternary system. In order to calculate the O–Pu–U ternary phase diagram, the interaction parameters of the excess Gibbs energies of the liquid and fluorite structure phase in the O–Pu–U system have been determined. The thermodynamic data for the liquid phase have been reassessed from the associated model in literatures to the ionic model using a least-square method. The thermodynamic data for the fluorite structure phase have been assessed using the oxygen potential data both in the hyper- and hypo-stoichiometric regions. The calculated ternary phase diagram reproduces the general features of the ternary phase diagram.