Research Uncovers Promising Advanced Nuclear Fuel Properties in Uranium Mononitride

Strategic Insights -

Recent studies have explored the unique properties of uranium mononitride (UN), a potential advanced nuclear fuel with high thermal conductivity and high fissile density. Researchers at North Carolina State University (NC State), supported by Westinghouse Electric Company and the United States Department of Energy (DOE), have conducted molecular dynamics (MD) simulations to investigate UN's diffusional creep. The research found that Nabarro-Herring creep is not dominant in the temperature range of 1700-2000 K, and the primary diffusional creep mechanism is Coble creep with an activation energy of 2.28 +/- 0.09 eV.

Key Takeaways:

  • The research discovered that Coble creep is the dominant diffusional creep mechanism in uranium mononitride (UN) for temperatures between 1700-2000 K.
  • The activation energy for this creep mechanism was calculated to be 2.28 +/- 0.09 eV, providing valuable insights into UN's thermal creep properties.
  • The study proposed a method to calculate the diffusional grain boundary width and its temperature dependence in polycrystals.
  • The effective grain boundary width of UN was measured as 2.69 +/- 0.08 nm, showing good agreement with the phenomenological Coble creep formula.
  • The research demonstrated the potential of combining the Coble creep model with a dislocation creep model to create a comprehensive thermal creep model for UN.
  • The findings of this study have implications for the development of advanced nuclear fuels and offer a new direction for research in the field of nuclear materials science.
  • The research involved a team of authors from North Carolina State University (NC State), including Benjamin Beeler, Mohamed Abdulhameed, Nermeen Elamrawy, Antoine Claisse, Conor O. T. Galvin and Michael W. D. Cooper.

Statistics:

  • The coble creep activation energy was measured as 2.28 +/- 0.09 eV.
  • The effective grain boundary width of UN was calculated as 2.69 +/- 0.08 nm.
  • The temperature range of 1700-2000 K was explored in the MD simulations.

Sources:

  • NewsRx, Reports from North Carolina State University (NC State) Highlight Recent Findings in Physics (Molecular-dynamics Study of Diffusional Creep In Uranium Mononitride). Journal of Physics Research. November 4, 2025; p 3250.
  • Molecular-dynamics Study of Diffusional Creep In Uranium Mononitride. Journal of Nuclear Materials, 2025;617.