Evaluation of thermal conductivity of zirconia-based inert matrix fuel by molecular dynamics simulation

Molecular dynamics (MD) simulations were performed using Born–Mayer–Huggins interatomic potentials with partially ionic model in order to evaluate the thermal conductivity of zirconia-based inert matrix fuel (IMF). The thermal conductivity was calculated at the equilibrium condition based on Green–Kubo theory and phenomenological equations. For ErxYyMzZr1−x−y−zO2−(x+y)/2 (where M = Ce or Pu), the thermal conductivity decreased with increase of y because of the presence of oxygen vacancies as the thermal resistance. It also slightly decreased with increase of z and temperature. However, significant difference could not be found in the thermal conductivity between Ce- and Pu-doped zirconia. The MD thermal conductivity of IMF was in good agreement with the literature data. Concerning the phenomenological coefficients, the cross-coupling effect between energy and charge fluxes was clearly observed at low z value and high temperatures for such zirconia systems.