Near surface stoichiometry in UO2: A density functional theory study
Abstract
The mechanisms of oxygen stoichiometry variation in UO2 at different temperature and oxygen partial pressure are important for understanding the dynamics of microstructure in these crystals. However, very limited experimental studies have been performed to understand the atomic structure of UO2 near surface and defect effects of near surface on stoichiometry in which the system can exchange atoms with the external reservoir. In this study, the near (110) surface relaxation and stoichiometry in UO2 have been studied with density functional theory (DFT) calculations. On the basis of the point-defect model (PDM), a general expression for the near surface stoichiometric variation is derived by using DFT total-energy calculations and atomistic thermodynamics, in an attempt to pin down the mechanisms of oxygen exchange between the gas environment and defected UO2. By using the derived expression, it is observed that, under poor oxygen conditions, the stoichiometry of near surface is switched from hyperstoichiometric at 300 K with a depth around 3 nm to near-stoichiometric at 1000 K and hypostoichiometric at 2000 K. Furthermore, at very poor oxygen concentrations and high temperatures, our results also suggest that the bulk of the UO2 prefers to be hypostoichiometric, although the surface is near-stoichiometric.
- Authors:
-
- Idaho National Lab. (INL), Idaho Falls, ID (United States)
- Univ. of Florida, Gainesville, FL (United States)
- Publication Date:
- Research Org.:
- Energy Frontier Research Centers (EFRC) (United States). Center for Materials Science of Nuclear Fuel (CMSNF); Idaho National Laboratory (INL), Idaho Falls, ID (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- OSTI Identifier:
- 1212694
- Grant/Contract Number:
- AC07-05ID14517
- Resource Type:
- Accepted Manuscript
- Journal Name:
- Journal of Chemistry
- Additional Journal Information:
- Journal Volume: 2015; Journal ID: ISSN 2090-9063
- Publisher:
- Hindawi
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Citation Formats
Yu, Jianguo, Valderrama, Billy, Henderson, Hunter B., Manuel, Michele V., and Allen, Todd. Near surface stoichiometry in UO2: A density functional theory study. United States: N. p., 2015.
Web. doi:10.1155/2015/142510.
Yu, Jianguo, Valderrama, Billy, Henderson, Hunter B., Manuel, Michele V., & Allen, Todd. Near surface stoichiometry in UO2: A density functional theory study. United States. https://doi.org/10.1155/2015/142510
Yu, Jianguo, Valderrama, Billy, Henderson, Hunter B., Manuel, Michele V., and Allen, Todd. Sat .
"Near surface stoichiometry in UO2: A density functional theory study". United States. https://doi.org/10.1155/2015/142510. https://www.osti.gov/servlets/purl/1212694.
@article{osti_1212694,
title = {Near surface stoichiometry in UO2: A density functional theory study},
author = {Yu, Jianguo and Valderrama, Billy and Henderson, Hunter B. and Manuel, Michele V. and Allen, Todd},
abstractNote = {The mechanisms of oxygen stoichiometry variation in UO2 at different temperature and oxygen partial pressure are important for understanding the dynamics of microstructure in these crystals. However, very limited experimental studies have been performed to understand the atomic structure of UO2 near surface and defect effects of near surface on stoichiometry in which the system can exchange atoms with the external reservoir. In this study, the near (110) surface relaxation and stoichiometry in UO2 have been studied with density functional theory (DFT) calculations. On the basis of the point-defect model (PDM), a general expression for the near surface stoichiometric variation is derived by using DFT total-energy calculations and atomistic thermodynamics, in an attempt to pin down the mechanisms of oxygen exchange between the gas environment and defected UO2. By using the derived expression, it is observed that, under poor oxygen conditions, the stoichiometry of near surface is switched from hyperstoichiometric at 300 K with a depth around 3 nm to near-stoichiometric at 1000 K and hypostoichiometric at 2000 K. Furthermore, at very poor oxygen concentrations and high temperatures, our results also suggest that the bulk of the UO2 prefers to be hypostoichiometric, although the surface is near-stoichiometric.},
doi = {10.1155/2015/142510},
journal = {Journal of Chemistry},
number = ,
volume = 2015,
place = {United States},
year = {Sat Aug 01 00:00:00 EDT 2015},
month = {Sat Aug 01 00:00:00 EDT 2015}
}
Web of Science
Works referenced in this record:
Surface reactions of uranium oxide powder, thin films and single crystals
journal, March 2010
- Idriss, H.
- Surface Science Reports, Vol. 65, Issue 3
Oxygen transport in off-stoichiometric uranium dioxide mediated by defect clustering dynamics
journal, March 2015
- Yu, Jianguo; Bai, Xian-Ming; El-Azab, Anter
- The Journal of Chemical Physics, Vol. 142, Issue 9
Computer simulation of defect clusters in UO2 and their dependence on composition
journal, January 2015
- Brincat, N. A.; Molinari, M.; Parker, S. C.
- Journal of Nuclear Materials, Vol. 456
Average structure and local configuration of excess oxygen in UO2+x
journal, March 2014
- Wang, Jianwei; Ewing, Rodney C.; Becker, Udo
- Scientific Reports, Vol. 4, Issue 1
Thermodynamic assessment of the uranium–oxygen system
journal, August 2002
- Guéneau, C.; Baichi, M.; Labroche, D.
- Journal of Nuclear Materials, Vol. 304, Issue 2-3
Non-stoichiometry, electrical conductivity and defect structure of hyper-stoichiometric UO2+x at 1000°C
journal, February 2000
- Kang, Sun-Ho; Lee, Jong-Ho; Yoo, Han-Ill
- Journal of Nuclear Materials, Vol. 277, Issue 2-3
The atomic structure of the UO2+x(110) surface and the effects of interstitial oxygen: an elevated-temperature STM study
journal, May 1998
- Muggelberg, C.; Castell, M. R.; Briggs, G. A. D.
- Surface Science, Vol. 402-404
Quantum mechanical vs. empirical potential modeling of uranium dioxide (UO2) surfaces: (111), (110), and (100)
journal, November 2006
- Skomurski, F. N.; Ewing, R. C.; Rohl, A. L.
- American Mineralogist, Vol. 91, Issue 11-12
Projector augmented-wave method
journal, December 1994
- Blöchl, P. E.
- Physical Review B, Vol. 50, Issue 24, p. 17953-17979
Ab initiomolecular dynamics for liquid metals
journal, January 1993
- Kresse, G.; Hafner, J.
- Physical Review B, Vol. 47, Issue 1, p. 558-561
First-principles study of defects and phase transition in UO 2
journal, October 2009
- Yu, Jianguo; Devanathan, Ram; Weber, William J.
- Journal of Physics: Condensed Matter, Vol. 21, Issue 43
Systematic Analysis of 4 f Core Photoemission Spectra in Actinide Oxides
journal, January 1991
- Yamazaki, Takao; Kotani, Akio
- Journal of the Physical Society of Japan, Vol. 60, Issue 1
Bubble formation and Kr distribution in Kr-irradiated UO2
journal, January 2015
- He, L. F.; Valderrama, B.; Hassan, A. -R.
- Journal of Nuclear Materials, Vol. 456
Atomic transport properties in UO2 and mixed oxides (U, Pu)O2
journal, January 1987
- Matzke, Hansjoachim
- Journal of the Chemical Society, Faraday Transactions 2, Vol. 83, Issue 7
Charge self-regulation upon changing the oxidation state of transition metals in insulators
journal, June 2008
- Raebiger, Hannes; Lany, Stephan; Zunger, Alex
- Nature, Vol. 453, Issue 7196
The surface properties of uranium dioxide
journal, August 1979
- Tasker, P. W.
- Surface Science, Vol. 87, Issue 2
Edge Electron Gas
journal, October 1998
- Kohn, Walter; Mattsson, Ann E.
- Physical Review Letters, Vol. 81, Issue 16
Theory of Metal Surfaces: Charge Density and Surface Energy
journal, June 1970
- Lang, N. D.; Kohn, W.
- Physical Review B, Vol. 1, Issue 12
Occupation matrix control of d- and f-electron localisations using DFT + U
journal, January 2014
- Allen, Jeremy P.; Watson, Graeme W.
- Phys. Chem. Chem. Phys., Vol. 16, Issue 39
The Effect of Uranium Cations on the Redox Properties of CeO2 Within the Context of Hydrogen Production from Water
journal, December 2014
- Scaranto, Jessica; Idriss, Hicham
- Topics in Catalysis, Vol. 58, Issue 2-3
Charge optimized many-body potential for the system
journal, February 2007
- Yu, Jianguo; Sinnott, Susan B.; Phillpot, Simon R.
- Physical Review B, Vol. 75, Issue 8
Surface reactions of uranium oxide powder, thin films and single crystals
journal, March 2010
- Idriss, H.
- Surface Science Reports, Vol. 65, Issue 3
Polygonization and high burnup structure in nuclear fuels
journal, August 1997
- Matzke, Hj.; Kinoshita, M.
- Journal of Nuclear Materials, Vol. 247
The atomic structure of the UO2+x(110) surface and the effects of interstitial oxygen: an elevated-temperature STM study
journal, May 1998
- Muggelberg, C.; Castell, M. R.; Briggs, G. A. D.
- Surface Science, Vol. 402-404
Atomic transport properties in UO2 and mixed oxides (U, Pu)O2
journal, January 1987
- Matzke, Hansjoachim
- Journal of the Chemical Society, Faraday Transactions 2, Vol. 83, Issue 7
Surface-stress effects on elastic properties. II. Metallic multilayers
journal, April 1994
- Streitz, F. H.; Cammarata, R. C.; Sieradzki, K.
- Physical Review B, Vol. 49, Issue 15
Limitation of the open-circuit voltage due to metastable intrinsic defects in Cu(In,Ga)Se2 and strategies to avoid these defects
conference, May 2008
- Lany, Stephan; Zunger, Alex
- 2008 33rd IEEE Photovolatic Specialists Conference
Works referencing / citing this record:
DFT+ U in Dudarev’s formulation with corrected interactions between the electrons with opposite spins: The form of Hamiltonian, calculation of forces, and bandgap adjustments
journal, July 2019
- Shishkin, M.; Sato, H.
- The Journal of Chemical Physics, Vol. 151, Issue 2