Molecular dynamics simulation of the pressure–volume–temperature data of xenon for a nuclear fuel

Oh, Jae-Yong; Koo, Yang-Hyun; Cheon, Jin-Sik; Lee, Byung-Ho; Sohn, Dong-Seong

doi:10.1016/j.jnucmat.2007.02.009

Cited by 14 publications

(5 citation statements)

References 12 publications

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“…Almost all the interstitials remain isolated and vacancies tend to cluster into polyhedral voids [38]. The equation of state of Xe gas phase also has been examined by experiments [39][40][41] and atomistic simulations [42]. During the past decade, the phase-field approach has been applied to study microstructure evolutions in irradiated materials such as gas bubble evolution in UO 2 nuclear fuels [43,44], interstitial loop growth kinetics [45], and radiation-induced segregation and precipitation [46,47].…”

Section: Gas Bubble Structures Have Been Examined In Post-irradiationmentioning

confidence: 99%

Formation mechanism of gas bubble superlattice in UMo metal fuels: Phase-field modeling investigation

Hu¹,

Burkes²,

Lavender³

et al. 2016

Journal of Nuclear Materials

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Nano-gas bubble superlattices are often observed in irradiated UMo nuclear fuels. However, the formation mechanism of gas bubble superlattices is not well understood. A number of physical processes may affect the gas bubble nucleation and growth; hence, the morphology of gas bubble microstructures including size and spatial distributions. In this work, a phase-field model integrating a first-passage Monte Carlo method to investigate the formation mechanism of gas bubble superlattices was developed. Six physical processes are taken into account in the model: 1) heterogeneous generation of gas atoms, vacancies, and interstitials informed from atomistic simulations; 2) one-dimensional (1-D) migration of interstitials; 3) irradiation-induced dissolution of gas atoms; 4) recombination between vacancies and interstitials; 5) elastic interaction; and 6) heterogeneous nucleation of gas bubbles. We found that the elastic interaction doesn't cause the gas bubble alignment, and fast 1-D migration of interstitials along <110> directions in the body-centered cubic U matrix causes the gas bubble alignment along <110> directions. It implies that 1-D interstitial migration along [110] direction should be the primary mechanism of an fcc gas bubble superlattice which is observed in bcc UMo alloys. Simulations also show that fission rates, saturated gas concentration, and elastic interaction all affect the morphology of gas bubble microstructures.

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Section: Gas Bubble Structures Have Been Examined In Post-irradiationmentioning

confidence: 99%

Formation mechanism of gas bubble superlattice in UMo metal fuels: Phase-field modeling investigation

Hu¹,

Burkes²,

Lavender³

et al. 2016

Journal of Nuclear Materials

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“…The properties of defectsin bcc U single crystals have been investigated via experiments [4,[11][12][13], density functional theory (DFT) [14][15][16][17][18], and molecular dynamics (MD) method [1,16,19,20].The results show that 1) Xe is stableas a substitutional defect, and Xe migrates through vacancy-assisted mechanisms, presumably as a complex consisting of one Xe and two vacancies (XeV 2 complex), 2) the dumbbell configurations of U interstitials along the [100] or [110] direction are energetically favored, and 3) the migration barrier of U interstitials is about 0.1 eV, which is much smaller than that of vacancies (0.5eV).The defect generation and spatial distribution during cascades in bcc U were simulated using MD methods [21,22].The results show that most of the surviving interstitials form a [100] or [110] dumbbell.Almost all the interstitials remain isolated, while vacancies tend to cluster into polyhedral voids [22].The equation of state (EOS) of the Xe gas phase has been examined by experiments [23][24][25] and atomistic simulations [26]. Very recently, Xiao et al simulated the pressure inside Xe bubbles with different Xe concentrations in bcc U10Mo alloys [27].…”

Section: Introductionmentioning

confidence: 99%

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

Joshi

Lavender

2017

Journal of Nuclear Materials

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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 superlattice formation are not well known.In this work, the molecular dynamics (MD) method 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 MD simulations, the embedded-atom method (EAM) potential of U10Mo-Xe[1] is employed. Initial gas bubbles with a low Xeconcentration(underpressured) are generated in a body-centered cubic(bcc)U10Mo single crystal.Then Xeatoms aresequentiallyadded into the bubbles one by one, and the evolution of pressure and dislocation emission around the bubbles is analyzed. The relationship between pressure, equilibrium Xe concentration, and radiusofthe bubblesis established.It was found that an overpressuredgas bubble emits partial dislocations witha Burgers vector along the <111> direction and a slip plane of (11-2). Meanwhile, dislocation loop punchout was not observed.The overpressured bubble also induces an anisotropic stress field. A tensile stress was found along <110> directions around the bubble, favoring the nucleation and formation of aface-centered cubic bubble superlattice in bccU10Mo fuels.

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“…However, recent experimental data [14] show that the pressure predicted by Ronchi is higher than the experimental values. Oh [15] used the exponential-6 interatomic potential to investigate the behaviors of Xe gas atoms with MD simulation. He obtained the reasonable pressure-volumetemperature data for Xe but did not propose an applicable EOS for Xe.…”

Section: Introductionmentioning

confidence: 99%

A modified equation of state for Xe at high pressures by molecular dynamics simulation

Xiao¹,

Long²

2014

Chinese Phys. B

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The exact equation of state (EOS) for the fission gas Xe is necessary for the accurate prediction of the fission gas behavior in uranium dioxide nuclear fuel. However, the comparison with the experimental data indicates that the applicable pressure ranges of existing EOS for Xe published in the literature cannot cover the overpressure of the rim fission gas bubble at the typical UO 2 fuel pellet rim structure. Based on the interatomic potential of Xe, the pressure-volume-temperature data are calculated by the molecular dynamics (MD) simulation. The results indicate that the data of MD simulation with Ross and McMahan's potential [M. Ross and A. K. McMahan 1980 Phys. Rev. B 21 1658] are in good agreement with the experimental data. A preferable EOS for Xe is proposed based on the MD simulation. The comparison with the MD simulation data shows that the proposed EOS can be applied at pressures up to 550 MPa and 3 GPa and temperatures 900 K and 1373 K respectively. The applicable pressure range of this EOS is wider than those of the other existing EOS for Xe published in the literature.

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Molecular dynamics simulation of the pressure–volume–temperature data of xenon for a nuclear fuel

Cited by 14 publications

References 12 publications

Formation mechanism of gas bubble superlattice in UMo metal fuels: Phase-field modeling investigation

Formation mechanism of gas bubble superlattice in UMo metal fuels: Phase-field modeling investigation

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

A modified equation of state for Xe at high pressures by molecular dynamics simulation

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