Surface alteration evidence for a mechanism of anoxic dissolution of UO2

Popel, Aleksej J. and Tan, Beng Thye and Gouder, Thomas and Lampronti, Giulio I. and Day, Jason and Eloirdi, Rachel and Seibert, Alice and Farnan, Ian (2019) Surface alteration evidence for a mechanism of anoxic dissolution of UO2. Applied Surface Science, 464. pp. 376-379. ISSN 0169-4332 DOI https://doi.org/10.1016/j.apsusc.2018.09.094

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Official URL: https://doi.org/10.1016/j.apsusc.2018.09.094

Abstract

A secondary phase has been observed to nucleate on the surface of UO2 in a solution with uranium concentration values of ∼10−9 mol/l. The UO2 was in the form of a 100 nm single crystalline film of UO2 epitaxially deposited on the (0 0 1) surface of a single crystalline silicon substrate. An extended (140 days) dissolution experiment with UO2 in contact with a solution in deoxygenated, deionised water, under an Ar atmosphere (∼0.1 O2 ppm) at ambient temperature (∼25 °C) suggests that uranium dioxide should dissolve and precipitate while remaining in the U4+ oxidation state to enable nucleation of a low solubility secondary phase. A mechanism for the anoxic dissolution of UO2 in deionised water is proposed that involves U4+ dissolution at defect sites that subsequently nucleate and precipitate in a less defective form.

Item Type: Article
Uncontrolled Keywords: 2018AREP; IA74
Subjects: 03 - Mineral Sciences
Divisions: 03 - Mineral Sciences
08 - Green Open Access
12 - PhD
Journal or Publication Title: Applied Surface Science
Volume: 464
Page Range: pp. 376-379
Identification Number: https://doi.org/10.1016/j.apsusc.2018.09.094
Depositing User: Sarah Humbert
Date Deposited: 08 Feb 2019 12:23
Last Modified: 08 Feb 2019 12:23
URI: http://eprints.esc.cam.ac.uk/id/eprint/4419

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