Radiolytic Corrosion of Uranium Dioxide: Role of Molecular Species

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• 作者：Ali Traboulsi ; Johan Vandenborre ; Guillaume Blain ; Bernard Humbert ; Jacques Barbet ; Massoud Fattahi
• 刊名：Journal of Physical Chemistry C
• 出版年：2014
• 出版时间：January 16, 2014
• 年：2014
• 卷：118
• 期：2
• 页码：1071-1080
• 全文大小：457K
• ISSN：1932-7455

文摘

In this work, the oxidative corrosion of UO₂ particles by molecular species produced by ⁴He²⁺ radiolysis of water (simulated by irradiation with a ⁴He²⁺ beam) has been investigated as a function of the absorbed dose under open and closed atmospheres. This work was carried out by coupling for the first time (1) characterization of the UO₂ surface after oxidation, (2) analysis of H₂ and H₂O₂ produced by water radiolysis, and (3) quantification of the uranium species leached into the solution during irradiation. Oxidation of the surface of the UO₂ particles was characterized by Raman spectroscopy. H₂ and H₂O₂ were analyzed by micro gas chromatography and UV鈥搗is spectrophotometry, respectively. Inductively coupled plasma mass spectrometry was used to quantify the soluble uranium species released into the solution. The results showed that, when the ultrapure water above the UO₂ particles was irradiated in an open atmosphere, metastudtite was formed on the UO₂ surface, indicating its oxidation by the H₂O₂ produced by water radiolysis. This oxidation was accompanied by migration of soluble uranium species [U(VI)] into the irradiated solution. After irradiation in a closed atmosphere, oxidation of the UO₂ surface and migration of soluble uranium species were limited due to the presence of H₂. The inhibition does not occur by direct effect of H₂ on H₂O₂ but more probably by adsorption of H₂ molecules on the UO₂ surface.