Design and application of GDC on EAST Tokamak

Zhou, Zhiping; Song, Yuntao; Hu, Jiansheng

doi:10.1016/j.fusengdes.2011.03.052

Cited by 16 publications

(11 citation statements)

References 8 publications

(9 reference statements)

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“…The EAST machine achieved a 101.2 s H-mode discharge target in 2017, and its next goal is to achieve more than 400 s in H-mode discharges. Its future goal is to achieve 1000 s [4][5][6]. Therefore, the divertor heat load will be over 15 MW m −2 in the future [7,8].…”

Section: Introductionmentioning

confidence: 99%

Conceptual design and heat transfer performance of a flat-tile water-cooled divertor target

Han

et al. 2021

Plasma Sci. Technol.

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The divertor target components for the Chinese fusion engineering test reactor (CFETR) and the future experimental advanced superconducting tokamak (EAST) need to remove a heat flux of up to ∼20 MW m −2 . In view of such a high heat flux removal requirement, this study proposes a conceptual design for a flat-tile divertor target based on explosive welding and brazing technology. Rectangular water-cooled channels with a special thermal transfer structure (TTS) are designed in the heat sink to improve the flat-tile divertor target's heat transfer performance (HTP). The parametric design and optimization methods are applied to study the influence of the TTS variation parameters, including height (H), width (W * ), thickness (T), and spacing (L), on the HTP. The research results show that the flat-tile divertor target's HTP is sensitive to the TTS parameter changes, and the sensitivity is T>L>W * >H. The HTP first increases and then decreases with the increase of T, L, and W * and gradually increases with the increase of H. The optimal design parameters are as follows: H=5.5 mm, W * =25.8 mm, T=2.2 mm, and L=9.7 mm. The HTP of the optimized flat-tile divertor target at different flow speeds and tungsten tile thicknesses is studied using the numerical simulation method. A flat-tile divertor mock-up is developed according to the optimized parameters. In addition, high heat flux (HHF) tests are performed on an electron beam facility to further investigate the mock-up HTP. The numerical simulation calculation results show that the optimized flat-tile divertor target has great potential for handling the steady-state heat load of 20 MW m −2 under the tungsten tile thickness <5 mm and the flow speed 7 m s −1 . The heat transfer efficiency of the flat-tile divertor target with rectangular cooling channels improves by ∼13% and ∼30% compared to that of the flat-tile divertor target with circular cooling channels and the ITER-like monoblock, respectively. The HHF tests indicate that the flat-tile divertor mock-up can successfully withstand 1000 cycles of 20 MW m −2 of heat load without visible deformation, damage, and HTP degradation. The surface temperature of the flat-tile divertor mock-up at the 1000th cycle is only ∼930 °C. The flat-tile divertor target's HTP is greatly improved by the parametric design and optimization method, and is better than the ITER-like monoblock and the flat-tile mock-up for the WEST divertor. This conceptual design is currently being applied to the engineering design of the CFETR and EAST flat-tile divertors.

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Section: Introductionmentioning

confidence: 99%

Conceptual design and heat transfer performance of a flat-tile water-cooled divertor target

Han

et al. 2021

Plasma Sci. Technol.

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“…Measurements on sputtered contaminant species and also their positive or negative charge are important for understanding surface treatment mechanisms and also their effect on plasmas. Glow discharge cleaning (GDC) using H2, D2, He, Ne, or Ar plasmas have been investigated for surface conditioning in current fusion devices [Lucia 2015;Maan 2020 IEEE;Jadeja 2022;Jadeja 2019;Goriaev 2019;Douai 2013;Zhou 2011;Hartl 2017;Tokitani 2005;Tanaka 2021] and ITER [Shimada 2011]. Incident ion energies of more than 200 V, accelerated by the applied anode potential for discharge, are expected for GDC [Hagelaar 2015].…”

Section: Introductionmentioning

confidence: 99%

Quantitative measurement of positive and negative ion species ejected from a Li-O-H surface by hydrogen and noble gas ion irradiation

Abe

Ostrowski

Maan

et al. 2023

Preprint

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We report sputtering yields of Li+, H−, O−, and OHx− ion species from an Li-O-H surface for H, D, He, Ne, and Ar ion irradiation at 45° incidence in the energy range of 30 − 2,000 eV. A Li film was deposited on a stainless steel target using Li evaporators in the LTX-β vessel, using the LTX-β Sample Exposure Probe (SEP), which includes an ultrahigh vacuum suitcase for transferring targets without significant contamination from air exposure. The SEP was used to transfer the Li-coated target from LTX-β to a separate Sample Exposure Station (SES) to perform ion exposure measurements. The SEP was also used for characterization of the Li-coated target utilizing X-ray photoelectron spectroscopy (XPS) in a different chamber, showing that the lithium film surface was oxidized. Ion exposures were performed using an electron cyclotron resonance (ECR) plasma source in the SES. Sputtered/ejected species were sampled by a quadrupole mass spectrometer with capabilities for detecting positive and negative ions, and an energy filter for determining the mean kinetic energy of the ejected ion species. All ion irradiations caused Li+ ions to be ejected, while causing impurity ions such as H+, H−, O− and OH− to be ejected. Our results for the sputtering yields of ejected ion species and their associated ion energies from a Li-O-H surface indicates that lithium sputtering is suppressed and impurity removal is enhanced due to the sheath potential at the divertor surface for fusion reactor applications.

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“…A significant disadvantage is the sputtering of materials in contact with the plasma, which leads to the deposition of metal films on the equipment located in it [8,9]. Despite this drawback, the technology of cleaning the wall of the vacuum chamber with a glow discharge plasma is the most common and is used in large installations, for example, in TEXTOR [8], Wendelstein 7-X [9][10][11], ASDEX-U [12], JET [13], LHD [14], EAST [15], SST-1 [16]. In the future, it is planned to use the GDC system at ITER [17].…”

Section: Introductionmentioning

confidence: 99%

“…Common to all systems is the use of a vacuum chamber wall as a cathode, and specially designed electrodes as anodes, which are placed into the vacuum volume. The number of electrodes (anodes) is usually from 2 (SST-1 [16], LHD [14]) to 4 (ASDEX-U [12], JET [13], EAST [15]). The electrodes (anodes) 10, are installed on Wendelstein 7-X [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Design and Application of Glow Discharge Cleaning at Uragan-2m Stellarator

Kovtun¹,

Moiseenko²,

Maznichenko³

et al. 2021

Problems of Atomic Science and Technology

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For the Uragan-2M stellarator, a glow discharge cleaning (GDC) system is developed. An overview of the GDC system design is presented. The first experimental studies of GDC in an argon atmosphere have been carried out. The dependence of the breakdown voltage on the argon pressure is determined. The current-voltage characteristics of the gas discharge were measured as a function of the working gas pressure also in presence of a magnetic field.

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Design and application of GDC on EAST Tokamak

Cited by 16 publications

References 8 publications

Conceptual design and heat transfer performance of a flat-tile water-cooled divertor target

Conceptual design and heat transfer performance of a flat-tile water-cooled divertor target

Quantitative measurement of positive and negative ion species ejected from a Li-O-H surface by hydrogen and noble gas ion irradiation

Design and Application of Glow Discharge Cleaning at Uragan-2m Stellarator

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