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Helium Retention and Release Characteristics of Multi-layer Pebbles for Pebble Drop Devertor

Research Project

Project/Area Number 13308024
Research Category

Grant-in-Aid for Scientific Research (A)

Allocation TypeSingle-year Grants
Section一般
Research Field Nuclear fusion studies
Research InstitutionOsaka University

Principal Investigator

NISHIKAWA Masahiro  Osaka University, Graduate School of Engineering, Department of Electronic, Information Systems and Energy Engineering, Professor, 大学院・工学研究科, 教授 (50029287)

Co-Investigator(Kenkyū-buntansha) UEDA Yoshio  Osaka University, Graduate School of Engineering, Department of Electronic, Information Systems and Energy Engineering, Associate Professor, 大学院・工学研究科, 助教授 (30193816)
OHTSUKA Yusuke  Osaka University, Graduate School of Engineering, Department of Electronic, Information Systems and Energy Engineering, Research Associate, 大学院・工学研究科, 助手 (70294048)
Project Period (FY) 2001 – 2004
Project Status Completed (Fiscal Year 2004)
Budget Amount *help
¥49,010,000 (Direct Cost: ¥37,700,000、Indirect Cost: ¥11,310,000)
Fiscal Year 2004: ¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2003: ¥18,720,000 (Direct Cost: ¥14,400,000、Indirect Cost: ¥4,320,000)
Fiscal Year 2002: ¥13,260,000 (Direct Cost: ¥10,200,000、Indirect Cost: ¥3,060,000)
Fiscal Year 2001: ¥12,740,000 (Direct Cost: ¥9,800,000、Indirect Cost: ¥2,940,000)
KeywordsPebble Divertore / Pumping and Recycling Performance / Helium Pumping / Pebble Curtain / Plasma Shielding / ECR discharge / Presheath / Multi-layer Pebble / プレシース / ラングミュアプローブ / ダイバータ / ダイバータプラズマ / 磁化プラズマ / 黒鉛材 / 高粒子束ビーム / 過渡吸蔵 / ベブルダイバータ
Research Abstract

One of the notable characteristics of a pebble drop divertor system is pumping performance of hydrogen isotopes and helium. In order to develop optimum fuel pumping and recycling system, the following subjects were studied : retention and release characteristics of hydrogen and helium by multi-layer pebbles, forming pebble curtain by pebble dropping through thin slits and evaluation of plasma shielding effects, plasma shielding mechanism by pebbles in plasma flow.
According to helium retention experiments, transient helium release from graphite samples decrease with increasing irradiation temperature in the case that irradiation temperature and desorption temperature was the same. Almost no helium retention was observed over 700 K even if transient release of He under high flux ion beam irradiation was taken into consideration. Helium pumping performance of the pebble drop divertor system was estimated from the experimental results and compared with a helium generation rate of ARIES-AT … More tokamak reactor concept. It was found that the pebble drop divertor system has enough pumping performance even at the pebble temperature of 673 K, which is slightly less than the retention limit ( 700K).
For the development of pebble falling system, the width of the slit for pebble discharge is determined to more than 3 cm in the case that the shading rate of incoming divertor plasma is more than 90%. This slit size does not cause any problem for the installation of the pebble falling system in actual fusion reactors.
For the study of plasma shielding mechanism by pebbles, simulation experiments by using an ECR plasma source was performed. In the experiments, hydrogen plasma produced by ECR discharge was diffused along magnetic field lines to a constant field region (100〜500 G). Then circular plates with the diameter of 2 cm and 5 cm (simulator for divertor pebbles) were inserted in the constant field plasma region to investigate the effects of pebbles on plasma parameters. Two dimensional distributions (radial and axial) of plasma parameters such as density, temperature, and potential were measured by a Langmuir probe. This measurement clearly showed two dimensional structure of the plasma presheath around the circular plates. Simulation results roughly agree with experimental results in the discharge gas pressure of 10 m Torr. Less

Report

(5 results)
  • 2004 Annual Research Report   Final Research Report Summary
  • 2003 Annual Research Report
  • 2002 Annual Research Report
  • 2001 Annual Research Report
  • Research Products

    (22 results)

All 2003 2002 2001 Other

All Journal Article (14 results) Publications (8 results)

  • [Journal Article] Pebble divertor concept for high power density fusion reactors2003

    • Author(s)
      M.Nishikawa
    • Journal Title

      Fusion Engineering and Design 65

      Pages: 375-379

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Experiments on helium pumping of pebble divertor2003

    • Author(s)
      K.Matsuhiro, T.Okui, M.Nishikawa
    • Journal Title

      Fusion Engineering and Design 65

      Pages: 433-437

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Estimation of multi-layer pebble flow in pebble divertor2003

    • Author(s)
      T.Okui, K.Matsuhiro, M.Nishikawa
    • Journal Title

      Fusion Engineering and Design 65

      Pages: 439-442

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Analysis of the interaction between the pebble and the plasma flow in pebble divertor2003

    • Author(s)
      T.Okui, K.Matsuhiro, M.Nishikawa
    • Journal Title

      Fusion Engineering and Design 66-68

      Pages: 437-440

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Pebble divertor concept for high power density fusion reactors2003

    • Author(s)
      M.Nishikawa
    • Journal Title

      Fusion Engineering and Design Vol.65

      Pages: 375-379

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Experiments on helium pumping of pebble divertor2003

    • Author(s)
      K.Matsuhiro, T.Okui, M.Nishikawa
    • Journal Title

      Fusion Engineering and Design Vol.65

      Pages: 433-437

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Estimation of multi-layer pebble flow in pebble divertor2003

    • Author(s)
      T.Okui, K.Matsuhiro, M.Nishikawa
    • Journal Title

      Fusion Engineering and Design Vol.65

      Pages: 439-442

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Analysis of the interaction between the pebble and the plasma flow in pebble divertor2003

    • Author(s)
      T.Okui, K.Matsuhiro, M.Nishikawa
    • Journal Title

      Fusion Engineering and Design Vol.66-68

      Pages: 437-440

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Performance characteristics of pebble flow for pebble divertor2002

    • Author(s)
      T.Okui, K.Matsuhiro, M.Nishikawa
    • Journal Title

      Fusion Engineering and Design 61-62

      Pages: 203-208

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Performance characteristics of pebble flow for pebble divertor2002

    • Author(s)
      T.Okui, K.Matsuhiro, M.Nishikawa
    • Journal Title

      Fusion Engineering and Design Vol.61-62

      Pages: 203-208

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Behavior of Falling Pebble for Pebble Divertor2001

    • Author(s)
      T.Okui, K.Matsuhiro, M.Isobe, M.Nishikawa
    • Journal Title

      Fusion Technology 39

      Pages: 934-938

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Operating windows of the pebble divertor2001

    • Author(s)
      K.Matsuhiro, M.Isobe, Y.Ohtsuka, Y.Ueda, M.Nishikawa
    • Journal Title

      Nuclear Fusion 41,No.7

      Pages: 827-832

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Behavior of Falling Pebble for Pebble Divertor2001

    • Author(s)
      T.Okui, K.Matsuhiro, M.Isobe, M.Nishikawa
    • Journal Title

      Fusion Technology Vol.39

      Pages: 934-938

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Journal Article] Operating windows of the pebble divertor2001

    • Author(s)
      K.Matsuhiro, M.Isobe, Y.Ohtsuka, Y.Ueda, M.Nishikawa
    • Journal Title

      Nuclear Fusion Vol.41 No.7

      Pages: 827-832

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      2004 Final Research Report Summary
  • [Publications] T.Okui, K.Matsuhiro, M.Nishikawa: "Analysis of the interaction between the pebble and the plasma flow in pebble divertor"Fusion Engineering and Design. 66-68. 437-440 (2003)

    • Related Report
      2003 Annual Research Report
  • [Publications] M.Nishikawa: "Pebble divertor concept for high power density fusion reactors"Fusion engineering and design. 65. 375-379 (2003)

    • Related Report
      2002 Annual Research Report
  • [Publications] K.Matsuhiro, T.Okui, M.Nishikawa: "Pumping effect of pebble divertor"Fusion engineering and design. 65. 433-437 (2003)

    • Related Report
      2002 Annual Research Report
  • [Publications] T.Okui, K.Matsuhiro, M.Nishikawa: "Estimation of multi-layer pebble flow in pebble divertor"Fusion engineering and design. 65. 439-442 (2003)

    • Related Report
      2002 Annual Research Report
  • [Publications] T.Okui, K.Matsuhiro, M.Nishikawa: "Performance characteristic of pebble flow for pebble divertor"Fusion engineering and design. 61-62. 203-208 (2003)

    • Related Report
      2002 Annual Research Report
  • [Publications] 西川雅弘: "固体移動表面式プラズマ対向機器概念"プラズマ・核融合学会誌. 78. 129-132 (2002)

    • Related Report
      2001 Annual Research Report
  • [Publications] K.Matsuhiro, M.lsobe, Y.Ohtsuka, Y.Ueda, M.Nishikawa: "Operating Windows of Pebble Divertor"Nuclear Fusion. 41. 827-832 (2001)

    • Related Report
      2001 Annual Research Report
  • [Publications] T.Okui, K.Matsuhiro, M.Isobe, M.Nishikawa: "Behavior of Falling Pebble for Pebble Divertor"Fusion Technology. 39. 934-938 (2001)

    • Related Report
      2001 Annual Research Report

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Published: 2001-04-01   Modified: 2016-04-21  

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