First-principles study of noble gas impurities and defects in UO<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msub><mml:mrow /><mml:mn>2</mml:mn></mml:msub></mml:math>

Thompson, Alexander; Wolverton, Christopher

doi:10.1103/physrevb.84.134111

Cited by 74 publications

(47 citation statements)

References 49 publications

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“…We calculate defects in uranium dioxide, including vacancy clusters, with and without xenon atoms, using density functional theory (DFT 3,34 (to the uranium f states) for strongly correlated systems as described by Dudarev 35 (here, spin-orbit coupling is neglected). Our energy cutoff was 500 eV with a 2x2x2 gamma centered k-point grid.…”

Section: A Dftmentioning

confidence: 99%

“…One possibility is that xenon diffuses interstitially, however, the octahedral interstitial position in uranium dioxide is highly strained and, consequently, energetically unfavorable. 3 Another possibility is that xenon diffuses on either the cation or anion sublattice. Matzke et al addressed this possibility through a series of experiments.…”

Section: Introductionmentioning

confidence: 99%

“…For example, if xenon occupied an interstitial site (9.7 eV / Xe atom), it would be energetically favorable to create a SD (4.09 eV / SD) and then have the xenon atom occupy that SD (1.06 eV / atom). 3 . SDs have more vacant space than an interstitial for the large xenon atoms, which roughly occupy the uranium position of the SD, and subsequently create less strain.…”

Section: Introductionmentioning

confidence: 99%

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Pathway and energetics of xenon migration in uranium dioxide

Thompson

Wolverton

2013

Phys. Rev. B

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Using a combination of Density Functional Theory (DFT), classical potentials, Molecular Dynamics (MD), and Nudged Elastic Band (NEB) calculations, we explore the diffusion of xenon in uranium dioxide (UO 2 ). We compare migration barriers of empirical potentials with DFT by performing NEB calculations and subsequently we use the DFT-validated empirical potentials to calculate vacancy clusters, with and without xenon, to determine the migration path and barrier of xenon in bulk UO 2 . We find (i) two empirical potentials out of four tested agree qualitatively with DFT derived energetics for Schottky defect migration, (ii) through the use of molecular dynamics with empirical potentials, we have found a new path for the diffusion of xenon-tetravacancy clusters (Xe + 2 V U + 2 V O ), (iii) this new path has an energy barrier significantly lower than previously reported paths by nearly 1 eV, (iv) we examine the physical contributions to the migration pathway and find the barrier is largely electrostatic and that xenon contributes very little to the barrier height, (v) once a uranium vacancy attaches to a xenonSchottky defect, the resulting xenon-tetravacancy cluster is strongly bound, and (vi) like xenon in a tetravacancy, a xenon-double Schottky defect can diffuse in a concerted manor with a comparable barrier to xenon in a tetravacancy, but two of the oxygen vacancies are only weakly bound to the defect.

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Section: A Dftmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Pathway and energetics of xenon migration in uranium dioxide

Thompson

Wolverton

2013

Phys. Rev. B

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“…Where possible, comparison has also been made to literature UO 2 DFT results [14,44,45,46]. Figure 4 shows similar trends for the trapping energies for Xe and Kr defects in CeO 2 , ThO 2 , UO 2 and PuO 2 between the empirical potential and the DFT methods used in this paper.…”

Section: Validation Of Empirical Parametersmentioning

confidence: 65%

“…DFT results (partially filled columns) are reported from the literature [14,44,45,46] and the present study (using Table 2) for comparison with the new empirical potential potential (solid columns).…”

Section: Gas--ion Separation (å)mentioning

confidence: 99%

Development of Xe and Kr empirical potentials for CeO₂, ThO₂, UO₂and PuO₂, combining DFT with high temperature MD

Cooper

Kuganathan

Burr

et al. 2016

J. Phys.: Condens. Matter

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Abstract. The development of embedded atom method (EAM) many-body potentials for actinide oxides and associated mixed oxide (MOX) systems has motivated the development of a complementary parameter set for gas-actinide and gas-oxygen interactions. A comprehensive set of density functional theory (DFT) calculations were used to study Xe and Kr incorporation at a number of sites in CeO 2 , ThO 2 , UO 2 and PuO 2 . These structures were used to fit a potential, which was used to generate molecular dynamics (MD) configurations incorporating Xe and Kr at 300 K, 1500 K, 3000 K and 5000 K. Subsequent matching to the forces predicted by DFT for these MD configurations was used to refine the potential set. This fitting approach ensured weighted fitting to configurations that are thermodynamically significant over a broad temperature range, while avoiding computationally expensive DFT-MD calculations. The resultant gas potentials were validated against DFT trapping energies and are suitable for simulating combinations of Xe and Kr in solid solutions of CeO 2 , ThO 2 , UO 2 and PuO 2 , providing a powerful tool for the atomistic simulation of conventional nuclear reactor fuel UO 2 as well as advanced MOX fuels.

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