Fusibility diagrams of systems based on magnesium and uranium chlorides

Thermodynamic Assessment of CrCl2 with NaCl–KCl–MgCl2–UCl3–UCl4 for Molten Chloride Reactor Corrosion Modeling

“…Kraus determined that UCl 3 and UCl 4 have only limited liquid miscibility, albeit from only a small number of phase equilibria experiments. This contradicts Desyatnik et al whose measurements indicate the formation of a eutectic and significant solubility of UCl 4 in UCl 3 (up to ∼45 mol % UCl 4 ). With only experimental phase equilibria data available, our attempts to model the UCl 4 –UCl 3 solid solution were unable to produce a satisfactory description that allowed the reproduction of the solidus and solvus without the use of an unjustifiably large number of parameters.…”

“…The calculated dilute activity coefficient values of liquid UCl 4 at lower temperatures are in very good agreement with those measured but diverge to a small extent at the higher temperature (Figure 10). Overall, the values are in the range of experimental uncertainty for open circuit potentiometric measurements of uranium chlorides, 57 and as the calculated γ U 4+ values were determined relative to those previously obtained for γ U 3+ , 23 well represents the measured liquidus values of Desyatnik et al 8 The eutectic temperature is reported by Desyatnik et al 8 8 who report an identical eutectic temperature of 813.2 K; however, their reported liquidus temperatures and eutectic compositions differ significantly. The values of Desyatnik et al 8 were considered more reliable as they are from differential thermal analysis (DTA) as opposed to the surface temperature technique of Sterlin and Artamonov.…”

“…The MgCl 2 –UCl 3 system was previously assessed by Beneš and Konings as having a sole eutectic based on the phase equilibria measurements of Desyatnik et al Our DSC measurements of two compositions in addition to those of Desyatnik et al are in good agreement with respect to the eutectic and liquidus temperatures (Table ). However, as the UCl 3 description in MSTDB-TC is not consistent with that used in the assessment of Benes and Konings, it was necessary to reassess the system, which was done using the constrained approach described in the Supporting Information.…”

“…Noting that the limiting slope of the UCl 3 -rich liquidus is well reproduced by assuming a simple eutectic system, the system assessment excludes the solid solution to avoid an excessively parameterized Gibbs energy description of the solid solution. The determined MQMQA interaction parameter of eq allowed the computing of the phase diagram of Figure which very well represents the measured liquidus values of Desyatnik et al The eutectic temperature is reported by Desyatnik et al as 818.2 K, but this is likely too low as it cannot be reconciled with that of the liquidus, and moreover, it coincides with the solid-transition temperature of 821 K reported by Fouque et al normalΔ G normalU 2 6 + normalU 4 + / Cl ( J mol − 1 ) = prefix− 4500 …”

Thermodynamic evaluation of the NaCl–MgCl2–UCl3–PuCl3 system

“…The thermodynamic assessment of the MgCl 2 -UCl 3 system was based on the experimental results by Desyatnik et al [16]. It is again a simple eutectic system with the experimentally obtained eutectic at T = 943 K and X UCl 3 ¼ 0:35.…”