Hydrogen trapping in tungsten: impact of helium irradiation and thermal cycling

Ialovega, Mykola; Bernard, E.; Bisson, Régis; Martin, Céline; Sakamoto, R.; Kreter, A.; Hodille, E.; Angot, Thierry; Grisolia, Christian

doi:10.1088/1402-4896/ab68bd

Cited by 16 publications

(25 citation statements)

References 25 publications

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“…When the cluster is over-pressurised, additional Frenkel pairs will be created. He bubbles can then form in W and their morphology depends on the exposure conditions 4 – 7 . Such bubbles have been observed using Molecular Dynamics (MD) 3 , 8 – 12 and Object Kinetic Monte Carlo 13 , 14 .…”

Section: Introductionmentioning

confidence: 99%

“…Eventually, when over-pressurised bubbles are close to the surface, bursting can occur as shown by Sefta et al in MD simulations 12 , 19 . Bursting greatly modifies surface morphologies by increasing the roughness and producing craters 4 and W-fuzz 7 , 20 – 23 . Moreover, He exposure can alter H retention in W 4 , 24 – 28 .…”

Section: Introductionmentioning

confidence: 99%

“…Bursting greatly modifies surface morphologies by increasing the roughness and producing craters 4 and W-fuzz 7 , 20 – 23 . Moreover, He exposure can alter H retention in W 4 , 24 – 28 .…”

Section: Introductionmentioning

confidence: 99%

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Influence of exposure conditions on helium transport and bubble growth in tungsten

Ialovega

Hodille

Mougenot

et al. 2021

Sci Rep

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Helium diffusion, clustering and bubble nucleation and growth is modelled using the finite element method. The existing model from Faney et al. (Model Simul Mater Sci Eng 22:065010, 2018; Nucl Fusion 55:013014, 2015) is implemented with FEniCS and simplified in order to greatly reduce the number of equations. A parametric study is performed to investigate the influence of exposure conditions on helium inventory, bubbles density and size. Temperature is varied from 120 K to 1200 K and the implanted flux of 100 eV He is varied from $$10^{17}\,{\text{m}^{-2}\, \text{s}^{-1}}$$ 10 17 m - 2 s - 1 to $$5 \times 10^{21}\, {\text{m}^{-2}\, \text{s}^{-1}}$$ 5 × 10 21 m - 2 s - 1 . Bubble mean size increases as a power law of time whereas the bubble density reaches a maximum. The maximum He content in bubbles was approximately $$4 \times 10^{8}$$ 4 × 10 8 He at $$5 \times 10^{21}\,{\text{m}^{-2}\, \text{s}^{-1}}$$ 5 × 10 21 m - 2 s - 1 . After 1 h of exposure, the helium inventory varies from $$5 \times 10^{16} \,{\text{m}^{-2}}$$ 5 × 10 16 m - 2 at low flux and high temperature to $$10^{25} \,{\text{m}^{-2}}$$ 10 25 m - 2 at high flux and low temperature. The bubbles inventory varies from $$5 \times 10^{12}$$ 5 × 10 12 bubbles m$$^{-2}$$ - 2 to $$2 \times 10^{19}$$ 2 × 10 19 bubbles m$$^{-2}$$ - 2 . Comparison with experimental measurements is performed. The bubble density simulated by the model is in quantitative agreement with experiments.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of exposure conditions on helium transport and bubble growth in tungsten

Ialovega

Hodille

Mougenot

et al. 2021

Sci Rep

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“…Molecular dynamics (MD) simulations show that a large amount of H can be accommodated around He bubbles [16,10,17]. Increased D retention was observed experimentally in a recent study after thermal cycling of He irradiated W samples where visible bubbles were observed [18]. Increased D retention was found experimentally also in keV-range ion beam experiments [19,20] which seems to be in contradiction to what was observed in mixed He-D plasma exposures.…”

Section: Introductionmentioning

confidence: 89%

“…In this contribution D retention and transport is studied in He-implanted and self-damaged W by exposing it to D atoms at 600 K with atom energy of 0.28 eV and flux of about 3.5×10 18 D/m 2 s.…”

Section: Introductionmentioning

confidence: 99%

Deuterium transport and retention in the bulk of tungsten containing helium: the effect of helium concentration and microstructure

Markelj¹,

Schwarz-Selinger

Pečovnik³

et al. 2020

Nucl. Fusion

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The effect of helium (He) on deuterium (D) retention and transport in the bulk of tungsten (W) was investigated. For this purpose samples were irradiated by 500 keV He ions at 300 K to different fluences in order to obtain He maximum concentrations of 1 at.%, 3.4 at.%, and 6.8 at.% in 0.84 µm depth. In order to discern the effect of irradiation damage caused by He implantation from the effect of the pure He presence on D retention, the W samples were irradiated at 300 K by 20 MeV tungsten ions in advance to create displacement damage in the crystal lattice to a damage dose of 0.23 dpa. The samples were exposed to a D atom beam at 600 K with a flux of 3.5 ×10 18 D/m 2 s to populate all the created defects. The D depth profiles were measured in situ during and at the end of exposure by nuclear reaction analysis to follow the dynamics of the D uptake. Thermal desorption spectra were collected ex situ at the end of the exposure. We show that D retention increases with implanted He fluence linearly following a D/He ratio of 0.29. We obtained peaking of D concentration at the position of maximum He concentration, reaching for the 6.8 at.% He sample three times higher D concentration (1.1 at. %) than obtained on high dpa W ion irradiated samples (0.37 at. %) for the same loading conditions. D retention and transport was also studied on He containing samples that were annealed to 1700 K. There was no reduction of D retention in the He zone but 80 % reduction in the only W irradiated zone was observed, meaning displacement damage was almost completely removed. In the He zone the D concentration increased to 1.35 at.% and this we attribute to trapping of D around He bubbles of 1.5 nm size created at the He peak maximum as obtained by transmission electron microscopy. Neither in the as He implanted nor the 1700 K annealed sample He did act as diffusion barrier. From this study one can conclude that in the main wall of a future fusion device the effect of He will not dominate D retention in tungsten but at high heat flux areas where displacement damage possibly anneals out He could accumulate in the material that it could eventually dominate over the effect of displacement damage.

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Deuterium trapping in the subsurface layer of tungsten pre-irradiated with helium ions

Harutyunyan

Gasparyan

Ryabtsev

et al. 2021

Journal of Nuclear Materials

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Hydrogen trapping in tungsten: impact of helium irradiation and thermal cycling

Cited by 16 publications

References 25 publications

Influence of exposure conditions on helium transport and bubble growth in tungsten

Influence of exposure conditions on helium transport and bubble growth in tungsten

Deuterium transport and retention in the bulk of tungsten containing helium: the effect of helium concentration and microstructure

Deuterium trapping in the subsurface layer of tungsten pre-irradiated with helium ions

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