Energetics of intrinsic point defects in uranium dioxide from electronic-structure calculations

Pankaj Nerikar, Taku Watanabe, James S. Tulenko, Simon R. Phillpot, Susan B. Sinnott

Research output: Contribution to journalArticle

105 Scopus citations

Abstract

The stability range of intrinsic point defects in uranium dioxide is determined as a function of temperature, oxygen partial pressure, and non-stoichiometry. The computational approach integrates high accuracy ab initio electronic-structure calculations and thermodynamic analysis supported by experimental data. In particular, the density functional theory calculations are performed at the level of the spin polarized, generalized gradient approximation and includes the Hubbard U term; as a result they predict the correct anti-ferromagnetic insulating ground state of uranium oxide. The thermodynamic calculations enable the effects of system temperature and partial pressure of oxygen on defect formation energy to be determined. The predicted equilibrium properties and defect formation energies for neutral defect complexes match trends in the experimental literature quite well. In contrast, the predicted values for charged complexes are lower than the measured values. The calculations predict that the formation of oxygen interstitials becomes increasingly difficult as higher temperatures and reducing conditions are approached.

Original languageEnglish (US)
Pages (from-to)61-69
Number of pages9
JournalJournal of Nuclear Materials
Volume384
Issue number1
DOIs
StatePublished - Jan 31 2009

All Science Journal Classification (ASJC) codes

  • Nuclear and High Energy Physics
  • Materials Science(all)
  • Nuclear Energy and Engineering

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