Mobility of hydrogen-helium clusters in tungsten studied by molecular dynamics

Grigorev, Petr; Terentyev, D.; Bonny, G.; Журкин, Е. Е.; Oost, G. Van; Noterdaeme, Jean-Marie

doi:10.1016/j.jnucmat.2016.03.022

Cited by 22 publications

(7 citation statements)

References 28 publications

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“…Due to the large He mobility [9,22] and attractive nature of He-He and He-vacancy [8,9] in the W lattice, large He-vacancy clusters are probably formed in our damaged crystal lattice. Because the diffusivity of a He cluster or a He-vacancy cluster is suppressed [22,23] we can assume He is accumulated in the implantation zone. The applied He fluence is still below the fluence where visible blisters would be formed on the surface [7].…”

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confidence: 99%

Hydrogen isotope accumulation in the helium implantation zone in tungsten

2017

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The influence of helium (He) on deuterium (D) transport and retention was studied experimentally in tungsten (W). Helium was implanted 1 μm deep into W to a maximum calculated concentration of 3.4 at.%. To minimize the influence of displacement damage created during the He implantation on D retention so-called self-damaged W was used. W was damaged by 20 MeV W ion bombardment and defects were populated by low-temperature D plasma at room temperature before He implantation.Deuterium depth profiling was performed in-situ during isochronal annealing in the temperature range from 300 K to 800 K. It is shown for the first time unambiguously that He attracts D and locally increases D trapping. Deuterium retention increased by a factor of two as compared to a non-He implanted W reference after sample annealing at 450 K. Rate equation modelling can explain the measured D depth profiles quantitatively when keeping the de-trapping parameters unchanged but only increasing the number of traps in the He zone. This bolsters the confidence in the theoretical calculations predicting that more hydrogen isotopes can be stored around a He cluster zone.

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confidence: 99%

Hydrogen isotope accumulation in the helium implantation zone in tungsten

2017

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“…As long as there is space, He atoms can aggregate with each other to form bubbles [32]. Even if there are no vacancies, dislocations, grain boundaries and other large spaces, He atoms can occupy the interstices of the lattice to form He bubbles by self-trapping [33][34][35].…”

Section: He Bubble Layer Barrier Effect On D Permeation Reductionmentioning

confidence: 99%

The effect of He-induced surface microstructure on D plasma-driven permeation through RAFM steel

Wang¹,

Zhou²,

Liu³

et al. 2022

Nucl. Fusion

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The effect of helium (He)-induced surface microstructure on D plasma-driven permeation through a reduced activation ferritic/martensitic (RAFM) steel CLF-1 has been studied. The CLF-1 steel is pre-exposed by He plasma with ion fluence of 1022-1024 He m-2 and an incident energy of 100 eV at 708 K. The following D plasma driven permeation (PDP) experiment is performed at 693 K. Steady-state D permeation flux decreases with the increase of He ion fluence. D diffusion coefficient is found not to be significantly affected by He pre-damage, while D reflection coefficient increases with the enhance of He ion fluence. Scanning electron microscope (SEM) and transmission electron microscope (TEM) analyses clearly reveal the evolutions of surface roughness and the He bubbles layer after He exposures. Elastic recoil detection (ERD) is used to identify He concentration depth profiles in the samples. Both the surface microstructure modification and the He bubble layer formation contribute to the reduction of D permeation.

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“…[41][42][43] or Kinetic Monte Carlo simulations [44]. Together with the data for diffusion and thermal stability of mixed He M -H N clusters reporter earlier [27], this paper provides the parameters needed for such simulations.…”

Section: A Set Of Ms and MD Simulations Was Performed In Order To Invmentioning

confidence: 99%

Molecular dynamics simulation of hydrogen and helium trapping in tungsten

Grigorev

Zinovev

Terentyev

et al. 2018

Journal of Nuclear Materials

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Tungsten has been chosen as the divertor armour material in ITER and is the main candidate material for plasma-facing components for future fusion reactors. Interaction of plasma components with the material leads to degradation of the performance and thus the lifetime of the in-vessel components. On top of that special attention is drawn to tritium retention in the reactors vessel from a safety point of view, since tritium is radioactive material. In order to gain better understanding of the mechanisms driving accumulation of plasma components in the material and subsequent degradation of the material, atomistic simulations are employed. The focus of this work is on so-called self trapping of H and He atoms or, in other words, Frenkel pair formation in bulk tungsten in the presence of H and He atoms. Two versions of a model embedded atom interatomic potential and a bond order potential were tested by comparing it with ab initio data regarding the binding properties of pure He and He-H-Vacancy clusters and energetics of Frenkel pair formation. As a result of Molecular Dynamics simulations at finite temperature, the values of critical H concentration

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Mobility of hydrogen-helium clusters in tungsten studied by molecular dynamics

Cited by 22 publications

References 28 publications

Hydrogen isotope accumulation in the helium implantation zone in tungsten

Hydrogen isotope accumulation in the helium implantation zone in tungsten

The effect of He-induced surface microstructure on D plasma-driven permeation through RAFM steel

Molecular dynamics simulation of hydrogen and helium trapping in tungsten

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