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This content will become publicly available on October 26, 2017

Title: Investigation of oxygen self-diffusion in PuO2 by combining molecular dynamics with thermodynamic calculations

In the present work, the defect properties of oxygen self-diffusion in PuO2 are investigated over a wide temperature (300–1900 K) and pressure (0–10 GPa) range, by combining molecular dynamics simulations and thermodynamic calculations. Based on the well-established cBΩ thermodynamic model which connects the activation Gibbs free energy of diffusion with the bulk elastic and expansion properties, various point defect parameters such as activation enthalpy, activation entropy, and activation volume were calculated as a function of T and P. Molecular dynamics calculations provided the necessary bulk properties for the proper implementation of the thermodynamic model, in the lack of any relevant experimental data. The estimated compressibility and the thermal expansion coefficient of activation volume are found to be more than one order of magnitude greater than the corresponding values of the bulk plutonia. As a result, the diffusion mechanism is discussed in the context of the temperature and pressure dependence of the activation volume.
Authors:
 [1] ;  [2] ;  [3] ;  [4] ;  [1]
  1. Technological Educational Institute of Crete (Greece); UNESCO Chair on Solid Earth Physics and Geohazards Risk Reduction (Greece)
  2. Imperial College, London (United Kingdom); Coventry Univ., Coventry (United Kingdom)
  3. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  4. Coventry Univ., Coventry (United Kingdom)
Publication Date:
OSTI Identifier:
1331292
Report Number(s):
LA-UR--16-28070
Journal ID: ISSN 2046-2069; RSCACL
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
RSC Advances
Additional Journal Information:
Journal Volume: 6; Journal Issue: 105; Journal ID: ISSN 2046-2069
Publisher:
Royal Society of Chemistry
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Nuclear Energy (NE)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS