Modeling Superionic Behavior of Plutonium Dioxide


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GÜNAY S. D. , AKGENC B., TAŞSEVEN Ç.

HIGH TEMPERATURE MATERIALS AND PROCESSES, vol.35, no.10, pp.999-1004, 2016 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 35 Issue: 10
  • Publication Date: 2016
  • Doi Number: 10.1515/htmp-2015-0133
  • Title of Journal : HIGH TEMPERATURE MATERIALS AND PROCESSES
  • Page Numbers: pp.999-1004

Abstract

The Bredig transition to the superionic phase indicated with the.-peak in C-p was highly expected for plutonium dioxide (PuO2) as other actinide dioxides. However, least-square fit and local smoothing techniques applied to the experimental enthalpy data of PuO2 in 1980s could not detect a.-peak in specific heat that might be due to too scattered and insufficient experimental data. Therefore, this issue has not been yet put beyond the doubts. In the current article, a superionic model of PuO2 is developed with partially ionic model of a rigid ion potential. Thermophysical properties were calculated in constant pressure-temperature ensemble using molecular dynamics simulation. The Bredig transition with vicinity of a lambda-peak in specific heat was successfully observed for the model system at about 2,100 K. Moreover, the experimental enthalpy change was well reproduced before and after the estimated transition temperature.