NuFuel & MMSNF 2015

First Workshop on Research into Nuclear Fuel in Europe
and Materials Modeling and Simulation for Nuclear Fuels Workshop
Karlsruhe, Germany, November 16th to 18th, 2015

Updated: Tue 08 Dec 2015, 14:27

Talk 5.1: Simulation and Measurement of Thermal Conductivity in UO2

Michael Cooper1, X.-Y. Liu1, D. A. Andersson1, M.J.D. Rushton2, R.W. Grimes2 and C.R. Stanek1
  • 1: Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM USA
  • 2: Department of Materials and Centre for Nuclear Engineering, Imperial College London, London. SW7 2AZ.

Abstract

To fully utilise nuclear fuel its material properties must be maintained under extreme conditions. Thermal conductivity is particularly important owing to its role in mitigating centreline fuel melting. Firstly, the role of UO2 magnetism in phonon scattering has been investigated experimentally. Furthermore, through the Callaway Model magnetism sufficiently accounts for the difference between molecular dynamics and experiment at low temperatures. By combining defect-phonon scattering (from molecular dynamics) with the magnetic contribution (from experiment), the Callaway Model can be parameterized to predict the degradation of UO2 thermal conductivity due to different fission products. Zr, Xe, La and Pu are all predicted to influence thermal conductivity to different degrees depending on their valance state and atomic size relative to the host lattice.