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Extreme multi-valence states in mixed actinide oxides

Epifano, E.; Naji, M.; Manara, D.; Scheinost, A. C.; Hennig, C.; Lechelle, J.; Konings, R. J. M.; Guéneau, C.; Prieur, D.; Vitova, T. ORCID iD icon 1; Dardenne, K. ORCID iD icon 1; Rothe, J. ORCID iD icon 1; Martin, P. M.
1 Institut für Nukleare Entsorgung (INE), Karlsruher Institut für Technologie (KIT)

To assure the safety of oxide-fuel based nuclear reactors, the knowledge of the atomic-scale properties of U1−yMyO2±x materials is essential. These compounds show complex chemical properties, originating from the fact that actinides and rare earths may occur with different oxidation states. In these mostly ionic materials, aliovalent cationic configurations can induce changes in the oxygen stoichiometry, with dramatic effects on the properties of the fuel. First studies on U1−yAmyO2±x indicated that these materials exhibit particularly complex electronic and local-structure configurations. Here we present an in-depth study of these compounds, over a wide compositional domain, by combining XRD, XAS and Raman spectroscopy. We provide evidences of the co-existence of four different cations (U4+, U5+, Am3+, Am4+) in U1−yMyO2±x compounds, which nevertheless maintain the fluorite structure. Indeed, we show that the cationic sublattice is basically unaffected by the extreme multi-valence states, whereas complex defects are present in the oxygen sublattice.

Verlagsausgabe §
DOI: 10.5445/IR/1000096843
Veröffentlicht am 29.07.2019
DOI: 10.1038/s42004-019-0161-0
Zitationen: 13
Web of Science
Zitationen: 16
Zitationen: 19
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Nukleare Entsorgung (INE)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 12.2019
Sprache Englisch
Identifikator ISSN: 2399-3669
KITopen-ID: 1000096843
HGF-Programm 32.01.04 (POF III, LK 01) Entw.u.Anpassung v.Speziationsmethoden
Weitere HGF-Programme 54.11.11 (POF IV, LK 01) Accelerator Operation, Research and Development
Erschienen in Communications chemistry
Verlag Nature Research
Band 2
Heft 1
Seiten 59
Vorab online veröffentlicht am 29.05.2019
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