Skip to Main content Skip to Navigation
Journal articles

On the O-rich domain of the U-Am-O phase diagram

Abstract : Uranium–Americium oxides U$_{1−y}$Am$_y$O$_{2±x}$ are promising candidates as possible transmutation targets for next generation nuclear reactors. In the context of a comprehensive investigation of their thermodynamic and thermal properties, the behaviour in oxidizing conditions is here studied. In a recent work, the behaviour in air of stoichiometric and sub-stoichiometric U$_{1−y}$Am$_y$O$_{2±x}$ compounds, with various Am content, was investigated by high-temperature X-ray Diffraction. Herein, the hyper-stoichiometric oxides obtained from that study are investigated by X-ray Absorption Spectroscopy. The new data, together with the previous XRD results, allow determining the exact compositions of the samples and hence obtaining phase diagram points in the O-rich domain of the U-Am-O system. Indeed, five phase diagram points at 1473 K are obtained: two tie-lines in the M$_4$O${9-}$M$_3$O$_8$ domain, for Am/(Am + U) = 0.10 and 0.15, one tie line in the MO$_{2+x-}$M$_3$O$_8$ domain, for Am/(Am + U) = 0.28, and two points in the single phase MO$_{2±x}$ domain, for higher americium concentration. From these data, it is also concluded that trivalent americium has a small solubility in the M$_4$O$_9$ and M$_3$O$_8$ phases.
Complete list of metadata
Contributor : Accord Elsevier CCSD Connect in order to contact the contributor
Submitted on : Monday, March 7, 2022 - 2:08:12 PM
Last modification on : Friday, August 5, 2022 - 10:37:45 AM
Long-term archiving on: : Wednesday, June 8, 2022 - 7:49:25 PM


Files produced by the author(s)


Distributed under a Creative Commons Attribution - NonCommercial 4.0 International License



E. Epifano, Romain Vauchy, Florent Lebreton, R. Lauwerier, A. Joly, et al.. On the O-rich domain of the U-Am-O phase diagram. Journal of Nuclear Materials, Elsevier, 2020, 531, pp.151986. ⟨10.1016/j.jnucmat.2020.151986⟩. ⟨cea-02529003⟩



Record views


Files downloads