Deuterium retention in neutron-irradiated single-crystal tungsten

Shimada, M.; Oya, Yasuhisa; Wampler, W.R.; Yamauchi, Yuji; Taylor, Chase N.; Garrison, Lauren M.; Buchenauer, D.; Hatano, Yuji

doi:10.1016/j.fusengdes.2018.04.094

Cited by 28 publications

(10 citation statements)

References 29 publications

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“…TDS measurements immediately performed after the plasma exposure showed a significant increase in the retention of deuterium in the neutron-irradiated tungsten samples. This increase in deuterium retention is due to the generation of displacement-damaged defects over the entire thickness of the samples [8][9][10][11][12][13][14][15][16][17][18]. Positron lifetime measurements performed in the previous study [18] showed that the neutron irradiation at around 563 K resulted in the formation of vacancies and vacancy clusters as large as V 10 .…”

Section: Resultsmentioning

confidence: 92%

“…As a potential material for PFCs in future fusion reactors, tungsten will be subjected to intensive fluxes of energetic deuterium and tritium and 14 MeV neutrons. Neutron irradiation generates displacements in the tungsten bulk and thus creates defects at which hydrogen isotopes are trapped [8][9][10][11][12][13][14][15][16][17][18]. One of the possible tritium removal methods is to heat the PFCs after the deuterium-tritium operation using the decay heat generated by the radioisotopes that appear in the PFCs due to neutron irradiation.…”

Section: Introductionmentioning

confidence: 99%

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Deuterium release from deuterium plasma-exposed neutron-irradiated and non-neutron-irradiated tungsten samples during annealing

et al. 2020

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We examine the effect of neutron irradiation on the release of deuterium from tungsten at 573 K to understand the efficiency of tritium removal by baking out at moderate temperatures. Tungsten samples, undamaged and neutron-irradiated to a damage level of approximately 0.016 displacements per atom, are exposed to low-energy (108 eV), high-flux (3.0 × 1021 to 9.4 × 1021 m−2 s−1) deuterium plasma at temperatures ranging from 573 to 773 K to an ion fluence of 1.1 × 1025 m−2. At each exposure temperature, two undamaged and two neutron-irradiated tungsten samples are exposed to plasma. The deuterium content in the tungsten samples is measured by thermal desorption spectrometry soon after the plasma exposure and after post-plasma annealing at 573 K for 30 h. It is found that: (i) the deuterium retention in the neutron-irradiated tungsten samples is significantly higher than that in the undamaged tungsten samples; (ii) annealing at 573 K of undamaged tungsten samples pre-exposed to deuterium plasma at 573–773 K leads to an almost complete (60%–99%) release of deuterium from the samples; (iii) annealing at 573 K of neutron-irradiated tungsten samples pre-exposed to deuterium plasma at 573–773 K leads to a significant (8%–20%) release of deuterium from the samples.

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Section: Resultsmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Deuterium release from deuterium plasma-exposed neutron-irradiated and non-neutron-irradiated tungsten samples during annealing

et al. 2020

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“…It is anticipated that tungsten divertor armour in a tokamak reactor will be exposed to high heat fluxes ( ̴ 10 MW/m 2 during steady state operation and ̴ 20 MW/m 2 during slow transients [4,5]), intense radiation with 14.1 MeV fusion neutrons and bombardment with ions, predominantly hydrogen and helium isotopes. A particular challenge is that hydrogen isotopes readily diffuse into the metal matrix, where they can substantially modify material properties and structure [6][7][8][9]. Trapping of deuterium at defects and self-trapping have been observed to lead to the formation of voids in the material and the emergence of surface blisters [7][8][9].…”

Section: Main Textmentioning

confidence: 99%

Transient grating spectroscopy of thermal diffusivity degradation in deuterium implanted tungsten

Reza

Zayachuk

et al. 2020

Scripta Materialia

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Graphical AbstractAbstract Using transient grating spectroscopy, we measure thermal diffusivity and surface acoustic wave speed in tungsten exposed to different fluences of deuterium plasma. Scanning electron microscopy (SEM) shows the formation of surface blisters that have similar morphology for all fluences considered. A significant reduction in thermal diffusivity and surface acoustic wave speed occurs as a result of plasma exposure. A saturation of the thermal diffusivity reduction with fluence is seen. Deuterium ion flux density appears to play a more important role in thermal diffusivity reduction than exposure time. These observations have important implications for plasma facing components in future fusion reactors.

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“…Complex physical and chemical processes are simplified by adjusting the governing equations, boundary conditions and fundamental parameters in these codes. They have been extensively used to make predictions for future nuclear devices and simulate experimental phenomena including D/He exposure as well as thermal desorption process [25][26][27].…”

Section: Introductionmentioning

confidence: 99%

Modelling of deuterium diffusion and thermal desorption in tungsten exposed to high-flux deuterium plasma

Sun,

Cheng,

Zhou

et al. 2023

Mater. Res. Express

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In nuclear fusion, hydrogen isotopes transportation in tungsten has been identified as a crucial process which could affect various key processes in the operation of a fusion device, such as tritium self-sustaining and operational safety. To enhance the understanding of deuterium diffusion and trapping in millimeter-thick tungsten under high-flux plasma conditions, we carried out a systematic simulation investigation on the deuterium plasma exposure and subsequent thermal desorption using the TMAP7 code based on experimental results. The simulation reveals that the defect concentration with a low de-trapping energy , as estimated solely from simulating thermal desorption, is lower than its actual density due to the temperature history of plasma exposure and subsequent cooling processes. Moreover, the growth rate of deuterium mobile concentration exhibits nonmonotonic behavior over time during plasma exposure, which strongly depends on the ratio of defect concentration with a high de-trapping energy to that with a low de-trapping energy. Additionally, we observed that the maximum deuterium diffusion depth does not follow a proportional relationship with the square root of exposure time, which is attributed to the growing number of plasma-induced defects and the reducing injection coefficient with increasing fluences. This work provides valuable insights into the understanding of deuterium transportation in tungsten during high-flux plasma exposure which could contribute to understanding and modelling of hydrogen isotopes recycling in future fusion devices.

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Deuterium retention in neutron-irradiated single-crystal tungsten

Cited by 28 publications

References 29 publications

Deuterium release from deuterium plasma-exposed neutron-irradiated and non-neutron-irradiated tungsten samples during annealing

Deuterium release from deuterium plasma-exposed neutron-irradiated and non-neutron-irradiated tungsten samples during annealing

Transient grating spectroscopy of thermal diffusivity degradation in deuterium implanted tungsten

Modelling of deuterium diffusion and thermal desorption in tungsten exposed to high-flux deuterium plasma

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