New Paper - "Fission Gas in Thoria"

N. Kuganathan — Wed, 04 Jan 2017 14:34:37 GMT

Our recent computational work using density functional theory on “Fission gas in thoria” has been accepted and is now available from the Journal of Nuclear Materials.

Navaratnarajah Kuganathan, Partha S. Ghosh, Conor OT. Galvin, Ashok K. Arya, Bijon K. Dutta, Gautam K. Dey, Robin W. Grimes, “Fission gas in thoria”, J. Nucl. Mater., 485 (2017) 47–55. doi:10.1016/j.jnucmat.2016.12.011

This study uses first-principles density functional theory together with a dispersion correction (DFT+D) to calculate the energetics of neutral and charged point defects and defect cluster geometries in ThO₂. It also investigates their interaction with Xe and Kr. ThO₂ has been identified as a possible alternative nuclear fuel, partly because spent ThO₂ fuels give rise to considerably smaller inventories of minor actinides, especially Pu. Furthermore, ThO₂ is a highly stable oxide, and exhibits higher thermal conductivity, higher melting temperature, higher corrosion resistance and lower thermal expansion compared to UO₂. At high fuel temperatures, fission gas atoms migrate and are accommodated at point defect sites in the fuel matrix. Over time some of these aggregate into bubbles. Formation of bubbles is important as it leads to swelling and degrades mechanical properties of the material. In order to understand fuel performance, it is necessary to understand the interaction of gas atoms with point defects.

New Paper and CRG Potential Update - Addition of Xe and Kr parameters for use with the actinide potential model

M.W.D. Cooper — Mon, 31 Oct 2016 11:52:29 GMT

Potential parameters have been derived for Xe and Kr in CeO₂, ThO₂, UO₂ and PuO₂.

The CRG model for actinide oxides has been effective at reproducing a wide range of properties for actinide oxides and CeO₂. Many problems relating to fuel performance revolve around the behaviour of the fission gases Xe and Kr in nuclear fuel. We have, thus, used a new approach, which combines DFT with MD at 300K, 1500K, 3000K and 5000K, to develop interactions for Xe and Kr in CeO₂, ThO₂, UO₂, PuO₂, and mixed oxides.

The fission-product model is described in our new paper:

M.W.D. Cooper, N. Kuganathan, P.A. Burr, M.J.D. Rushton, R.W. Grimes, C.R. Stanek and D.A. Andersson, “Development of Xe and Kr empirical potentials for CeO₂, ThO₂, UO₂ and PuO₂, combining DFT with high temperature MD”, Journal of Physics: Condensed Matter, 28 (2016) 405401. doi:10.1088/0953–8984/28/40/405401

The website has been updated to include the new parameter set. Additionally, the support files for LAMMPS have also been updated.

Atomistic Simulation Group (Posts about fission-product)

New Paper - "Fission Gas in Thoria"

New Paper and CRG Potential Update - Addition of Xe and Kr parameters for use with the actinide potential model