Thermodynamic model of the oxidation of Ln-doped UO2
Abstract Ln-doped UO2 is often considered as a model system of spent nuclear fuel (SNF) helping to reveal effects of fission and activation products on its chemical stability. Comparing thermodynamics of UO2-UO3 and LnO1.5-UO2-UO3 systems provides a means to understand the phenomenon of an increased...
| Hauptverfasser: | , , , |
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| Format: | Artikel |
| Sprache: | English |
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Nature Portfolio
2023-10-01
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| Schriftenreihe: | Scientific Reports |
| Online Zugang: | https://doi.org/10.1038/s41598-023-42616-x |
| Zusammenfassung: | Abstract Ln-doped UO2 is often considered as a model system of spent nuclear fuel (SNF) helping to reveal effects of fission and activation products on its chemical stability. Comparing thermodynamics of UO2-UO3 and LnO1.5-UO2-UO3 systems provides a means to understand the phenomenon of an increased resistivity of Ln-doped UO2 to oxidation in air relative to pure UO2. Here a thermodynamic model is developed and is applied to investigate detailed phase changes occurring along the oxidation of Ln-doped fluorite to U3O8. The study proposes that an enhanced resistivity to oxidation of Ln-doped UO2 is likely caused by a thermodynamically driven partitioning of Ln between a fluorite-type phase and a U3O8 polymorph, which at ambient temperatures becomes hindered by slow diffusion. |
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| ISSN: | 2045-2322 |