کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6476860 | 1426199 | 2017 | 7 صفحه PDF | دانلود رایگان |
- Enthalpies of mixing of UO2 - ThO2 and UO2 - ZrO2 systems have been measured.
- Volume mismatch linearly depends on interaction parameter in related systems.
- UO2 - ZrO2 is an exception to this correlation showing zero heat of mixing.
The enthalpies of formation of cubic urania - thoria (c-ThxU1âxO2+y) and urania - zirconia (c-ZrxU1âxO2, x < 0.3) solid solutions at 25 °C from end-member binary oxides (c-UO2, and c-ThO2 or m-ZrO2) have been measured by high temperature oxide melt solution calorimetry. The enthalpies of mixing for both systems are zero within experimental error. The interaction parameters for binary solid solutions MO2 - Mâ²O2 (M, Mâ²Â = U, Th, Ce, Zr, and Hf), fitted by regular and subregular thermodynamic models using both calorimetric and computational data, increase linearly with the corresponding volume mismatch. Cubic UO2 - ZrO2 appears to be an exception to this correlation and shows a zero heat of mixing despite large size mismatch, suggestive of some short-range ordering and/or incipient phase separation to mitigate the strain. The incorporation of ZrO2 into UO2 stabilizes the system and makes it a potential candidate for immobilization and disposal of nuclear waste.
Journal: The Journal of Chemical Thermodynamics - Volume 114, November 2017, Pages 48-54