skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Oxidative Corrosion of the UO 2 (001) Surface by Nonclassical Diffusion

Abstract

Uranium oxide is integral to every stage of the nuclear fuel cycle, from mining through fuel fabrication and use, to waste disposal and environmental cleanup. Its chemical and mechanical stability are intricately linked to the concentration of interstitial O atoms within the structure and the oxidation state of U. We have previously shown that, during corrosion of the UO 2 (111) surface under either 1 atm of O 2 gas or oxygenated water at room temperature, oxygen interstitials diffuse into the substrate to form a superlattice with three-layer periodicity. In the current study, we used surface X-ray scattering to reveal the structure of the oxygen diffusion profile beneath the (001) surface. The first few layers below the surface oscillate strongly in their surface-normal lattice parameters, suggesting preferential interstitial occupation of every other layer below the surface, which is geometrically consistent with the interstitial network that forms below the oxidized (111) surface. Deeper layers are heavily contracted and indicate that the oxidation front penetrates ~52 Å below the (001) surface after 21 days of dry O 2 gas exposure at ambient pressure and temperature. X-ray photoelectron spectroscopy implies U is present as U(IV), U(V), and U(VI).

Authors:
ORCiD logo [1];  [2];  [3];  [3];  [3]; ORCiD logo [4];  [1]
  1. Univ. of Chicago, Chicago, IL (United States)
  2. Univ. of Michigan, Ann Arbor, MI (United States); Chicago State Univ., Chicago, IL (United States)
  3. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  4. SLAC National Accelerator Lab., Menlo Park, CA (United States). Stanford Synchrotron Radiation Lightsource (SSRL)
Publication Date:
Research Org.:
Univ. of Chicago, IL (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Chemical Sciences, Geosciences & Biosciences Division; USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1508051
Report Number(s):
DOE-UCHICAGO-14466-12
Journal ID: ISSN 0743-7463
Grant/Contract Number:  
FG02-94ER14466
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Langmuir
Additional Journal Information:
Journal Volume: 33; Journal Issue: 46; Journal ID: ISSN 0743-7463
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES

Citation Formats

Stubbs, Joanne E., Biwer, Craig A., Chaka, Anne M., Ilton, Eugene S., Du, Yingge, Bargar, John R., and Eng, Peter J. Oxidative Corrosion of the UO 2 (001) Surface by Nonclassical Diffusion. United States: N. p., 2017. Web. doi:10.1021/acs.langmuir.7b02800.
Stubbs, Joanne E., Biwer, Craig A., Chaka, Anne M., Ilton, Eugene S., Du, Yingge, Bargar, John R., & Eng, Peter J. Oxidative Corrosion of the UO 2 (001) Surface by Nonclassical Diffusion. United States. doi:10.1021/acs.langmuir.7b02800.
Stubbs, Joanne E., Biwer, Craig A., Chaka, Anne M., Ilton, Eugene S., Du, Yingge, Bargar, John R., and Eng, Peter J. Mon . "Oxidative Corrosion of the UO 2 (001) Surface by Nonclassical Diffusion". United States. doi:10.1021/acs.langmuir.7b02800. https://www.osti.gov/servlets/purl/1508051.
@article{osti_1508051,
title = {Oxidative Corrosion of the UO 2 (001) Surface by Nonclassical Diffusion},
author = {Stubbs, Joanne E. and Biwer, Craig A. and Chaka, Anne M. and Ilton, Eugene S. and Du, Yingge and Bargar, John R. and Eng, Peter J.},
abstractNote = {Uranium oxide is integral to every stage of the nuclear fuel cycle, from mining through fuel fabrication and use, to waste disposal and environmental cleanup. Its chemical and mechanical stability are intricately linked to the concentration of interstitial O atoms within the structure and the oxidation state of U. We have previously shown that, during corrosion of the UO2 (111) surface under either 1 atm of O2 gas or oxygenated water at room temperature, oxygen interstitials diffuse into the substrate to form a superlattice with three-layer periodicity. In the current study, we used surface X-ray scattering to reveal the structure of the oxygen diffusion profile beneath the (001) surface. The first few layers below the surface oscillate strongly in their surface-normal lattice parameters, suggesting preferential interstitial occupation of every other layer below the surface, which is geometrically consistent with the interstitial network that forms below the oxidized (111) surface. Deeper layers are heavily contracted and indicate that the oxidation front penetrates ~52 Å below the (001) surface after 21 days of dry O2 gas exposure at ambient pressure and temperature. X-ray photoelectron spectroscopy implies U is present as U(IV), U(V), and U(VI).},
doi = {10.1021/acs.langmuir.7b02800},
journal = {Langmuir},
issn = {0743-7463},
number = 46,
volume = 33,
place = {United States},
year = {2017},
month = {10}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Save / Share: