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Abstract
UO2 is particularly susceptible to oxidation. The oxidation processes and the phases formed as a result are widely studied. In the oxidised phases defect clusters form, although their structure and properties are unclear. Thus, we examine fluorite based U3O7 phases to identify the types of defect present in a 36 atom unit cell. We predict that at this stoichiometry, defective structures form oxygen clusters and that split quad-interstitial clusters are the most thermodynamically stable defects. These are associated with a volume contraction compared to UO2, in line with experimental measurements. Incorporation of oxygen is always associated with oxidation of uranium atoms to U5+, although a single calculation leads to a U6+ ion as well. As this system is relatively unstable, it is proposed that U4+ and U5+ are the preferred oxidation states at U3O7 stoichiometry.
Original language | English |
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Pages (from-to) | 724-729 |
Number of pages | 6 |
Journal | Journal of Nuclear Materials |
Volume | 467 |
Issue number | Part 2 |
DOIs | |
Publication status | Published - 1 Dec 2015 |
Keywords
- Cuboctahedral cluster
- DFT
- Split di-interstitial cluster
- Split quad-interstitial cluster
- Split tri-interstitial cluster
- UO
- Willis cluster
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Dive into the research topics of 'Density functional theory calculations of defective UO2 at U3O7 stoichiometry'. Together they form a unique fingerprint.Projects
- 1 Finished
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Nanostructured Thermoelectric Oxides for Energy Generation: A Combined Experimental and Modelling Investigation
Parker, S. (PI)
Engineering and Physical Sciences Research Council
1/04/12 → 31/03/15
Project: Research council
Equipment
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High Performance Computing (HPC) Facility
Chapman, S. (Manager)
University of BathFacility/equipment: Facility