Thermodynamic model of the oxidation of Ln-doped UO2

Autor: V. L. Vinograd, A. A. Bukaemskiy, G. Deissmann, G. Modolo
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Scientific Reports, Vol 13, Iss 1, Pp 1-15 (2023)
Druh dokumentu: article
ISSN: 2045-2322
DOI: 10.1038/s41598-023-42616-x
Popis: 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.
Databáze: Directory of Open Access Journals
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