Final published version
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Point defects and non-stoichiometry in thoria
AU - Murphy, S. T.
AU - Cooper, M. W. D.
AU - Grimes, R. W.
PY - 2014/12/1
Y1 - 2014/12/1
N2 - Thoria is a possible alternative to urania as a nuclear fuel. In order to adopt thoria it is necessary to gain a thorough understanding of the defect processes that control its macroscopic properties. Here we perform density functional theory simulations coupled with chemical potentials calculated using simple thermodynamics, to explore the defect chemistry in ThO2 over a wide range of temperatures and oxygen partial pressures. The results predict the hypostoichiometric, ThO2 - x regime to be characterised by V-O(2+) defects charge compensated by conduction band electrons. The simulations also highlight the importance of the poroxo-oxygen interstitial defect, which is predicted to form with a significantly higher concentration than octahedral oxygen interstitial defects under hyperstoichiometric, ThO2 + x, conditions. Despite this thoria is not expected to accommodate a significant oxygen excess, which agrees with experimental observations. (C) 2014 Elsevier B.V. All rights reserved.
AB - Thoria is a possible alternative to urania as a nuclear fuel. In order to adopt thoria it is necessary to gain a thorough understanding of the defect processes that control its macroscopic properties. Here we perform density functional theory simulations coupled with chemical potentials calculated using simple thermodynamics, to explore the defect chemistry in ThO2 over a wide range of temperatures and oxygen partial pressures. The results predict the hypostoichiometric, ThO2 - x regime to be characterised by V-O(2+) defects charge compensated by conduction band electrons. The simulations also highlight the importance of the poroxo-oxygen interstitial defect, which is predicted to form with a significantly higher concentration than octahedral oxygen interstitial defects under hyperstoichiometric, ThO2 + x, conditions. Despite this thoria is not expected to accommodate a significant oxygen excess, which agrees with experimental observations. (C) 2014 Elsevier B.V. All rights reserved.
KW - Thoria
KW - Point defects
KW - DFT
KW - Conductivity
KW - LATTICE-PARAMETER
KW - SELF-DIFFUSION
KW - CONDUCTION
KW - OXYGEN
KW - THO2
U2 - 10.1016/j.ssi.2014.09.017
DO - 10.1016/j.ssi.2014.09.017
M3 - Journal article
VL - 267
SP - 80
EP - 87
JO - Solid State Ionics
JF - Solid State Ionics
SN - 0167-2738
ER -