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 5.9: Ab initio determination of gas atoms migration energy in UN

Antoine Claisse, Luca Messina and Pär Olsson
  • KTH Royal Institute of Technology, Stockholm, Sweden


Nitride fuels are being considered as an accident-tolerant option for both thermal and fast reactors, since their thermo-mechanical properties could allow for higher safety margins. However, R&D is still greatly needed, and in particular, the thermal diffusion coefficients of Xe and Kr reported in the literature differ by several (tens of) orders of magnitude.

This work proposes to refine this value by determining migration barriers in the DFT framework. To avoid meta-stable states, the occupation matrix control minimization scheme is used. The diffusion coefficient of Xe is then calculated by applying a self consistent mean field method [1] to the FCC antiferromagnetic sublattice of this alloy. The activation energy that is found is well within the experimental range.

  1. Nastar, Philos. Mag 85,32 (2005)