Phase equilibrium of PuO2-x - Pu2O3 based on first-principles calculations and configurational entropy change

Satoshi Minamoto, Masato Kato, Kenji Konashi

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Combination of an oxygen vacancy formation energy calculated using first-principles approach and the configurational entropy change treated within the framework of statistical mechanics gives an expression of the Gibbs free energy at large deviation from stoichiometry of plutonium oxide PuO2. An oxygen vacancy formation energy 4.20 eV derived from our previously first-principles calculation was used to evaluate the Gibbs free energy change due to oxygen vacancies in the crystal. The oxygen partial pressures then can be evaluated from the change of the free energy with two fitting parameters (a vacancy-vacancy interaction energy and vibration entropy change due to induced vacancies). Derived thermodynamic expression for the free energy based on the SGTE thermodynamic data for the stoichiometric PuO2 and the Pu 2O3 compounds was further incorporated into the CALPHAD modeling, then phase equilibrium between the stoichiometric Pu2O 3 and non-stoichiometric PuO2-x were reproduced.

Original languageEnglish
Pages (from-to)338-341
Number of pages4
JournalJournal of Nuclear Materials
Issue number3
Publication statusPublished - 2011 May 31

ASJC Scopus subject areas

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


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