Chemical thermodynamic representation of (U, Pu, Am)O2−x

The oxygen potential isotherms of (U, Pu, Am)O2−x were represented by a chemical thermodynamic model proposed by Lindemer et al. It was assumed in the present model that (U, Pu, Am)O2−x consisted of the chemical species [UO2], [PuO2], [Pu4/3O2], [AmO2] and [Am5/4O2] in a pseudo-quaternary system by treating the reduction rates of Pu and Am as identical; furthermore an interaction between [Am5/4O2] and [UO2] was introduced. The agreement between analytical and experimental isotherms was good, but the analytical values slightly overestimated the experimental values especially in the case of lower Am content. Adding an interaction between [Am5/4O2] and [PuO2] to the model resulted in a better representation.