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Title: Atomistic simulations of thermodynamic properties of Xe gas bubbles in U10Mo fuels

Authors:
ORCiD logo; ORCiD logo; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1396914
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Journal of Nuclear Materials
Additional Journal Information:
Journal Volume: 490; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-10-04 15:29:44; Journal ID: ISSN 0022-3115
Publisher:
Elsevier
Country of Publication:
Netherlands
Language:
English

Citation Formats

Hu, Shenyang, Setyawan, Wahyu, Joshi, Vineet V., and Lavender, Curt A. Atomistic simulations of thermodynamic properties of Xe gas bubbles in U10Mo fuels. Netherlands: N. p., 2017. Web. doi:10.1016/j.jnucmat.2017.04.016.
Hu, Shenyang, Setyawan, Wahyu, Joshi, Vineet V., & Lavender, Curt A. Atomistic simulations of thermodynamic properties of Xe gas bubbles in U10Mo fuels. Netherlands. doi:10.1016/j.jnucmat.2017.04.016.
Hu, Shenyang, Setyawan, Wahyu, Joshi, Vineet V., and Lavender, Curt A. 2017. "Atomistic simulations of thermodynamic properties of Xe gas bubbles in U10Mo fuels". Netherlands. doi:10.1016/j.jnucmat.2017.04.016.
@article{osti_1396914,
title = {Atomistic simulations of thermodynamic properties of Xe gas bubbles in U10Mo fuels},
author = {Hu, Shenyang and Setyawan, Wahyu and Joshi, Vineet V. and Lavender, Curt A.},
abstractNote = {},
doi = {10.1016/j.jnucmat.2017.04.016},
journal = {Journal of Nuclear Materials},
number = C,
volume = 490,
place = {Netherlands},
year = 2017,
month = 7
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on April 18, 2018
Publisher's Accepted Manuscript

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  • Xe gas bubble superlattice formation is observed in irradiated uranium–10 wt% molybdenum (U10Mo) fuels. However, the thermodynamic properties of the bubbles (the relationship among bubble size, equilibrium Xe concentration, and bubble pressure) and the mechanisms of bubble growth and superlattice formation are not well known. In this work, molecular dynamics is used to study these properties and mechanisms. The results provide important inputs for quantitative mesoscale models of gas bubble evolution and fuel performance. In the molecular dynamics simulations, the embedded-atom method (EAM) potential of U10Mo-Xe (Smirnova et al. 2013) is employed. Initial gas bubbles with low Xe concentration aremore » generated in a U10Mo single crystal. Then Xe atom atoms are continuously added into the bubbles, and the evolution of pressure and dislocation emission around the bubbles is analyzed. The relationship between pressure, equilibrium Xe concentration, and radius of the bubbles is established. It was found that the gas bubble growth is accompanied by partial dislocation emission, which results in a star-shaped dislocation structure and an anisotropic stress field. The emitted partial dislocations have a Burgers vector along the <111> direction and a slip plane of (11-2). Dislocation loop punch-out was not observed. A tensile stress was found along <110> directions around the bubble, favoring the nucleation and formation of a face-centered cubic bubble superlattice in body-centered cubic U10Mo fuels.« less
  • We study computationally the formation of thermodynamics and morphology of silicon self-interstitial clusters using a suite of methods driven by a recent parameterization of the Tersoff empirical potential. Formation free energies and cluster capture zones are computed across a wide range of cluster sizes (2 < N{sub i} < 150) and temperatures (0.65 < T/T{sub m} < 1). Self-interstitial clusters above a critical size (N{sub i} ∼ 25) are found to exhibit complex morphological behavior in which clusters can assume either a variety of disordered, three-dimensional configurations, or one of two macroscopically distinct planar configurations. The latter correspond to the well-known Frank and perfect dislocation loops observed experimentally in ion-implantedmore » silicon. The relative importance of the different cluster morphologies is a function of cluster size and temperature and is dictated by a balance between energetic and entropic forces. The competition between these thermodynamic forces produces a sharp transition between the three-dimensional and planar configurations, and represents a type of order-disorder transition. By contrast, the smaller state space available to smaller clusters restricts the diversity of possible structures and inhibits this morphological transition.« less
  • The thermodynamic mixing properties for isometric Th{sub x}Ce{sub 1-x}O{sub 2}, Ce{sub x}Zr{sub 1-x}O{sub 2}, and Th{sub x}Zr{sub 1-x}O{sub 2} were determined using quantum-mechanical calculations and subsequent Monte-Carlo simulations. Although the Th{sub x}Ce{sub 1-x}O{sub 2} binary indicates exsolution below 600 K, the energy gain due to exsolution is small (E{sub exsoln}=1.5 kJ/(mol cations) at 200 K). The energy gain for exsolution is significant for the binaries containing Zr; at 1000 K, E{sub exsoln}=6 kJ/(mol cations) for the Ce{sub x}Zr{sub 1-x}O{sub 2} binary, and E{sub exsoln}=17 kJ/(mol cations) for the Th{sub x}Zr{sub 1-x}O{sub 2} binary. The binaries containing Zr have limited miscibilitymore » and cation ordering (at 200 K for x=0.5). At 1673 K, only 4.0 and 0.25 mol% ZrO{sub 2} can be incorporated into CeO{sub 2} and ThO{sub 2}, respectively. Solid-solution calculations for the tetragonal Th{sub x}Zr{sub 1-x}O{sub 2} binary show decreased mixing enthalpy due to the increased end-member stability of tetragonal ZrO{sub 2}. Inclusion of the monoclinic ZrO{sub 2} is predicted to further reduce the mixing enthalpy for binaries containing Zr. - Graphical abstract: Temperature-composition phase diagram showing miscibility gaps for the isometric Th{sub x}Ce{sub 1-x}O{sub 2}, isometric Ce{sub x}Zr{sub 1-x}O{sub 2}, isometric Th{sub x}Zr{sub 1-x}O{sub 2}, and tetragonal Th{sub x}Zr{sub 1-x}O{sub 2} binaries at low composition (0« less
  • Atomic structures and energies of symmetrical {l_angle}001{r_angle} tilt grain boundaries (GB{close_quote}s) in diamond have been calculated over a wide range of misorientation angle using a many-body analytic potential, and for some selected short-period grain boundaries with tight-binding and first-principles density-functional methods. The grain boundary energies from the tight-binding and first-principles methods are about 75{percent} of those calculated with the analytic bond-order potential. The energy rankings of the GB{close_quote}s calculated with the empirical potential, however, are similar to that calculated from the tight-binding and the density functional approaches. Atomic-level energy and stress distributions calculated with the bond-order potential reveal relations betweenmore » local interface reconstruction and the extent and value of hydrostatic and shear stresses. From the calculated local volume strain and hydrostatic stress fields, the atomic bulk moduli are evaluated, and zones of different elastic behavior in the vicinity of the interface are defined. {copyright} {ital 1999} {ital The American Physical Society}« less