In-situ high resolution photoelectron spectroscopy study on interaction of sodium with UO.sub.2+x./sub. film (0 ≤ x ≤ 1)

0553306 - FZÚ 2022 RIV NL eng J - Journal Article
Andrello, C. - Gouder, T. - Favergeon, L. - Desgranges, L. - Tereshina-Chitrova, Evgenia - Havela, L. - Konings, R.J.M. - Eloirdi, R.
In-situ high resolution photoelectron spectroscopy study on interaction of sodium with UO_2+x film (0 ≤ x ≤ 1).
Journal of Nuclear Materials. Roč. 545, Mar. (2021), č. článku 152646. ISSN 0022-3115. E-ISSN 1873-4820
Institutional support: RVO:68378271
Keywords : sodium * interaction * UO₂ * UO_2+x * UO₃ * film * NaUO₃ * XPS * XRD
OECD category: Inorganic and nuclear chemistry
Impact factor: 3.555, year: 2021
Method of publishing: Open access

We studied in-situ the interaction of sodium metal with UO2+x (0 ≤ x ≤ 1) using thin films prepared by sputter deposition on Au substrate. X-ray Photoelectron Spectroscopy (XPS) and Grazing Incidence X-Ray Diffraction (GIXRD) characterized films before and after interaction. The results show that sodium does not reduce stoichiometric UO2 at room temperature. Molecular and atomic oxygen affect differently the oxidation of uranium and sodium. The wetting of the gold by the sodium is much more important when sodium is oxidised by atomic oxygen. Atomic oxygen seems to play the same role as the interstitial oxygen present in the UO2+x film. The oxygen dissociation may be the limiting step of sodium oxidation on gold and on UO2. Heat treatment of sodium on UO3 at about 773 K leads to the formation of the NaUO3 film. Once U(V) is formed, it stays stable up to at least 973 K, the temperature at which shrinkage of the film is observed.
Permanent Link: http://hdl.handle.net/11104/0328301