Phase diagram analysis of (U,Pu)O2−x sub-system

In situ high temperature X-Ray diffraction study of the phase equilibria in the UO2–PuO2–Pu2O3 system

“…The extent of the miscibility gap in temperature was found to be in very good agreement with various experimental data for y 0.60, in particular with DTA results at y ¼ 0.30 [6,19,20]. Gu eneau et al and Agarwal et al [14] representations are both in good agreement with HT-XRD data of Markin et Street at y ¼ 0,42 [5]. For higher Pu contents, the two descriptions differ.…”

“…However, the authors mainly focused on the UO 2 ePuO 2 stoichiometric pseudo binary system and did not investigate the region UO 2 ePuO 2 ePu 2 O 3 in detail. Agarwal et al [14] studied the miscibility gap with a thermochemical model but their approach does not allow the prediction of all the two phase regions of the phase diagram as only the cubic fluorite phase is modelled. Gu eneau et al [10] recently published a thermodynamic model of the UePueO system based on the CALPHAD method [15] and the use of the Thermo-Calc Software [16].…”

Structural studies of the phase separation in the UO2–PuO2–Pu2O3 ternary system

“…These data might also be useful to further improve thermodynamic assessments of this system already proposed, especially in the Pu-rich domain [12][13][14].…”

High Temperature X-ray Diffraction Study of the Oxidation Products and Kinetics of Uranium–Plutonium Mixed Oxides

“…13,14 Judging by the results of previous studies, 2,15 the U−Pu−O system, with small additions of Pu, up to 20−30%, exhibits similar behavior and can present a wide range of nonstoichiometry for all compositions. Since physical and chemical properties change with the O/M ratio and are different for each oxidation product, 11,13 it is crucial to determine precisely the phase boundaries and oxidation mechanisms in the hyperstoichiometric region UO 2 −PuO 2 −U 3 O 8 .…”

“…The ternary system U–Pu–O has been extensively studied for a range of compositions and at various temperatures, but still, data on some domains remains scarce. Numerous studies have been conducted in the PuO 2 –UO 2 –Pu 2 O 3 region, − leading to a fairly good understanding of the hypo-stoichiometric part of the phase diagram. The development of this type of fuels also requires studying the oxidation products and kinetics for the purposes of fuel elaboration methods, better understanding and modeling of long-term storage, − behavior under accident conditions, fuel–cladding interactions and predicting fuel restructuring.…”