Modelling zirconium hydrides using the special quasirandom structure approach

Wang, H.; Chroneos, Alexander; Jiang, Chao; Schwingenschlögl, Udo

doi:10.1039/c3cp50624j

Cited by 25 publications

(22 citation statements)

References 28 publications

(27 reference statements)

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“…Economically, the higher density fuels exhibit improved uranium loading allowing manufacturers to sell the assemblies at a premium. More importantly, the safety characteristics of such fuels can be improved markedly over conventional UO 2 pellets held within a Zr-alloy cladding (materials can be chosen with better oxidation resistance [1] or lower susceptibility for degradation due to hydrogen pick-up [2][3][4], for example), and the enrichment of the fuel can be reduced owing to the greater 235 U density.…”

Section: Introductionmentioning

confidence: 98%

“…The densities of U 3 Si and U 3 Si 2 are 15.4 g/cm 3 and 12.2 g/cm 3 , respectively, with maximum uranium loadings of 14.6 g/cm 3 and 11.3 g/cm 3 , respectively [5]. In comparison, uranium dioxide has a density of 10.96 g/cm 3 [6] with a maximum uranium loading of 9.66 g/cm 3 . Additionally, as the compounds exhibit metallic bonding, the thermal conductivities are significantly higher than UO 2 [7], especially after irradiation [8,9].…”

Section: Introductionmentioning

confidence: 99%

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Structural stability and fission product behaviour in U3Si

Middleburgh

Burr

King

et al. 2015

Journal of Nuclear Materials

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Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Structural stability and fission product behaviour in U3Si

Middleburgh

Burr

King

et al. 2015

Journal of Nuclear Materials

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“…The SQS method was used as an efficient and reliable tool in modelling disorder in a number of oxides and perovskites. [29][30][31][32] Electronic interactions between ions are studied using the crystal orbital Hamilton population (COHP)…”

Section: Methodsmentioning

confidence: 99%

Sc and Nb dopants in SrCoO3 modulate electronic and vacancy structures for improved water splitting and SOFC cathodes

Tahini

Tan

Zhou

et al. 2017

Energy Storage Materials

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SrCoO 3 is a promising material in the field of electrocatalysis. Difficulties in synthesising the material in its cubic phase have been overcome by doping it with Sc and Nb ions [Mater. Horiz. 2015, 2, 495-501]. Using ab initio calculations and special quasi random structures we undertake a systematic study of these dopants in order to elucidate the effect of doping on electronic structure of the SrCoO 3 host and the formation of oxygen vacancies. We find that while the overall electronic structure of SrCoO 3 is preserved, increasing the Sc fraction leads to a decrease of electrical conductivity, in agreement with earlier experimental work. For low Sc and Nb doping fractions we find that the oxygen vacancy formation increases relative to undoped SrCoO 3 . However, as the dopants concentration is increased the vacancy formation energy drops significantly, indicating a strong tendency to accommodate high concentration of oxygen vacancies and hence non-stoichiometry. This is explained based on the electronic instabilities caused by the presence of Sc ions which weakens the B-O interactions as well as the increased degree of electron delocalization on the oxygen sublattice. Sc dopants also shift the p-band centre closer to the Fermi level, which can be associated with experimentally reported improvements in oxygen evolution reactions. These findings provide crucial baseline information for the design of better electrocatalysts for oxygen evolution reactions as well as fuel-cell cathode materials.

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“…In this study, 3 different SQS cells are simulated containing 48, 52 and 56 H atoms, along with 32 Zr atoms. The SQS method has been recently applied to this system in order to model bulk parameters 28 . The 3 most representative SQS cells in that paper are used again here.…”

Section: Cell Configurationsmentioning

confidence: 99%

The thermodynamics of hydride precipitation: The importance of entropy, enthalpy and disorder

et al. 2014

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The thermodynamics of H/α-Zr solid solution and zirconium hydride phases were studied using density functional theory. Disorder in ζ, γ and δ hydrides and solid solutions were modelled using a statistically significant number of randomly generated structures in combination with special quasirandom structures and solid solutions with a range of concentrations. This is used in conjunction with a calculation of thermodynamic parameters of the system, including the temperature dependent sensible enthalpy, configurational entropy and vibrational entropy of the different crystals in the system, developed from phonon density of states. It was found that precipitation of hydrides is not thermodynamically favourable for Zr-H solid solutions containing less than 300 ppm H, suggesting that a mechanism must cause local concentration of H atoms to a greater amount than found globally in experimental samples containing hydrides. Temperature drives the reaction in the direction of solution, primarily due to entropic effects. Generally, γ hydride is the most stable phase, although it is very close in energy to the δ-phase. The sensible enthalpy of precipitation assists in stabilising HCP hydrides, and the configurational entropy change during precipitation favours FCC hydrides. None of the thermodynamic contributions are found to be negligible in driving precipitation.arXiv:1401.5637v1 [cond-mat.mtrl-sci] 22 Jan 2014 2

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Modelling zirconium hydrides using the special quasirandom structure approach

Cited by 25 publications

References 28 publications

Structural stability and fission product behaviour in U3Si

Structural stability and fission product behaviour in U3Si

Sc and Nb dopants in SrCoO3 modulate electronic and vacancy structures for improved water splitting and SOFC cathodes

The thermodynamics of hydride precipitation: The importance of entropy, enthalpy and disorder

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