Deuterium plasma driven permeation behavior in a Chinese reduced activation martensitic/ferritic steel CLF-1

Liu, Hao-Dong; Zhou, Hui; Xu, Yu-Ping; Lyu, Yi-Ming; Wang, Lu; Ding, Fang; Luo, Guang–Nan

doi:10.1016/j.jnucmat.2018.11.012

Cited by 13 publications

(16 citation statements)

References 16 publications

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“…For comparison, in DD or RR regime the PDP flux ratio should be a constant at a fixed temperature. Based on this consideration, previous PDP experiments [7,[21][22][23] have shown that it is the RD regime for ∼mm thick RAFM steels under low energy hydrogen plasma exposure. Equation ( 6) suggests that for RDlimited hydrogen PDP, steady-state permeation flux is related to the recombination process on the upstream surface and bulk diffusion, but not recombination on the downstream surface.…”

Section: Theoretical Considerationsmentioning

confidence: 82%

Hydrogen isotope plasma-driven permeation through RAFM steel: isotope exchange and helium irradiation effect

Yang

et al. 2022

Nucl. Fusion

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Hydrogen isotope exchange in CLAM steel was investigated by plasma-driven permeation measurements in the temperature range of ~670-920 K. It was found that as introducing H into D plasma, the permeation flux of HD increased while that of D2 decreased. The total D permeation flux, however, remained almost unchanged. Such a result allowed the analysis of isotope replacement and showed that the reduction of D2 is balanced by the rise of HD. In addition, the formation of HD was found to be closely related to the H and D contents in plasma. Hydrogen isotopic effects on H and D plasma dissociation/ionization rate and on incident flux were evaluated by measuring plasma parameters including electron temperature and electron density using a triple Langmuir probe. The correlation between isotope effects on ionization rate in the plasma and isotope effects in the permeation flux was discussed. He plasma pre-irradiation and seeding during D plasma-driven permeation were also conducted to investigate the He effects on D diffusion. The total D permeation flux was found to be reduced by He seeding. Data analysis of Langmuir probe showed that ionization rate of D plasma was influenced by He seeding. Besides, under simultaneous D + He irradiation, He atoms were preferentially trapped at the defects resulting in a shallower D concentration gradient that described the observed decrease in D permeation rate. He plasma pre-irradiation was found to reduce D permeation flux with a much slow breakthrough to reach steady-state. The amount of D trapped at He-induced defects was derived quantitatively from the transient permeation curves. It is believed that He bubbles formed at the near surface act as trapping sites of D atoms, leading to a reduced effective diffusion coefficient and an enhanced retention in the material.

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Section: Theoretical Considerationsmentioning

confidence: 82%

Hydrogen isotope plasma-driven permeation through RAFM steel: isotope exchange and helium irradiation effect

Yang

et al. 2022

Nucl. Fusion

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“…He pre-exposure and D permeation experiments were both performed on the linear plasma device PREFACE at the Institute of Plasma Physics, Chinese Academy of Sciences. More details about PREFACE have been published in previous works [19,20]. The He and D plasmas were produced by a 2.45 GHz microwave source (figure 1(a)).…”

Section: He Pre-exposure and D Permeation Experimentsmentioning

confidence: 99%

“…For steady-state PDP taking place in the recombinationdiffusion regime [19] the hydrogen surface concentration at a polished surface (S 0 = S s ) can be expressed by,…”

Section: Surface Roughness 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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“…In recent years, HIs solution and diffusion in tungsten [28][29][30], copper [31] and other metals [32,33] have been investigated by plasma-driven permeation and gas-driven permeation experiments. Due to the low HIs diffusion coefficient in tungsten, the thickness of the samples used in these experiments is very thin as tens of microns.…”

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 plasma driven permeation behavior in a Chinese reduced activation martensitic/ferritic steel CLF-1

Cited by 13 publications

References 16 publications

Hydrogen isotope plasma-driven permeation through RAFM steel: isotope exchange and helium irradiation effect

Hydrogen isotope plasma-driven permeation through RAFM steel: isotope exchange and helium irradiation effect

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

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

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