Tritium retention and erosion/deposition of first wall materials

2007 Fiscal Year Final Research Report Summary

• Project/Area Number: 17206092
• Research Category: Grant-in-Aid for Scientific Research (A)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Nuclear fusion studies
• Research Institution: Kyushu University
• Principal Investigator: TANABE Tetsuo Kyushu University, Advanced Energy Engineering Science, Prof. (00029331)
• Co-Investigator(Kenkyū-buntansha): OHYA Kaoru Tokushima University, 大学院・ソシオテクノサイエンス研究部, Prof. (10108855) ; SAKAWA Youichi Osaka University, Laser Fusion Center, Assoc. Prof. (70242881) ; HIROHATA Yuko Hokkaido University, Department of Nuclear Eng., Assoc. Prof. (00189896) ; MIYA Naoyuki Japan Atomic Energy Institute, 那珂研究所・核融合研究開発部門, Principal Researcher (60343901) ; MASAKI Kei Japan Atomic Energy Institute, 核融合研究開発部門, Researcher (10354648)
• Project Period (FY): 2005 – 2007
• Keywords: Plasma wall interactions / Carbon materials / erosion / Deposition / Hydrogen retention / Tritium / Tritium removal / Laser ablation

Research Abstract

Retention of hydrogen isotopes (H, D, and 1) and erosion/deposition in plasma facing carbon materials as well as dust sampling in JT-60U and the results are studied and compared with those of JET. In D-D discharge machines like JT-60U, tritium produced by D-D reaction does not fully lose its initial energy of 1 MeV and is implanted into plasma facing wall more than 1μm in depth. Hence tritium retention profile is separated from carbon deposition profiles. On the other hand, in JT-60U, H+D retention profiles in the diverter region are well correlated with the carbon deposition profiles and the deposition dominated inner diverter tiles show high retention, while the erosion dominated outer diverter tiles show low retention. Nevertheless the retained amount in the redeposited layers is smaller than those observed in JET, which is attributed to temperature rise of the redeposited layers probably owing to their poor thermal contact to the substrate. Carbon deposition on the plasma shadowed area and remote area like pumping ducts is very small and only small amount of dust is collected. Low deposition in the remote area in JT-60U could be attributed to the precise alignment of diverter tiles both toroidally and poloidally. It is suggested that divertor geometry could have rather strong effects on carbon deposition or carbon transport.
Pulsed-laser induced desorption of hydrogen from co-deposits on JT-60 open-divertor tile was also investigated. The fundamental (1064 nm) and fourth harmonic (266 nm) emission of a 20 ps-Nd: YAG laser were used, and dependences of hydrogen desorption on laser intensity IL and wavelength λ were studied. Hydrogen-desorption efficiency, defined as the ratio between the number of desorbed hydrogen by laser irradiation and that of hydrogen retained in the ablated volume, was largest in the region, where strong ionization of C+ occurred, and was larger for λ = 266 nm, in which a laser photon can cut C-H bond, compared with that for λ=1064 nm. For the ablative removal of hydrogen, a short-wavelength and high-power laser is desirable.

Research Products

• [Journal Article] Tritium distribution measurement of JET Mk IISRP divertor tiles (2007)
  • Author(s): T.Tanabe, K.Sugiyama, 他5名
  • Journal Title: J.Nucl.Mater 363-365 Pages: 960-965
  • Description: 「研究成果報告書概要(和文)」より
  • Peer Reviewed
• [Journal Article] Hydrogen Retention and Carbon Deposition in Plasma Facing Components and the Shadowed Area of JT-60U (2007)
  • Author(s): K. Masaki, T., Tanabe, Y. Hirohata, et. al.
  • Journal Title: Nuclear Fusion 47 Pages: 1577-1582
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Properties of hydrogen desorption from co-deposits on JT-60 graphite tile by pulsed laser ablation (2007)
  • Author(s): D., Watanabe, Y., Sakawa, T., Shibahara, K., Sugiyama, T., Shoji, K., Yamazaki, T., Tanabe
  • Journal Title: J. Nucl. Mater. 363-365 Pages: 972-976
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Modeling of Asymmetric Redeposition Distribution between Inner and Outer Regions of the W-shaped Divertor in JT-60U (2007)
  • Author(s): K., Ohya, K., Inai, T., Tanabe, H., Takenaga
  • Journal Title: J. Nucl. Mater 363-365 Pages: 78-85
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Ion beam analysis of H/D retention in the near surface layers of JT-60U plasma facing wall tiles (2007)
  • Author(s): K., Sugiyama, T., Hayashi, K., Krieger, M., Mayer, K., Masaki, N., Miya, T., Tanabe
  • Journal Title: J. Nucl. Mater 363-365 Pages: 949-954
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Hydrogen isotopes retention in JT-60U (2007)
  • Author(s): Y., Hirohata, T., Tanabe, Y., Oya, K., Okuno, K., Masaki, N., Miya
  • Journal Title: J. Nucl. Mater 363-365 Pages: 854-861
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Pulsed-laser ablation of co-deposits on JT-60 graphite tile T. Shibahara, T. Tanabe, Y. Hirohata, et. al. Hydrogen isotope retention of JT-60U W-shaned divertor tiles exposed to DD discharges (2007)
  • Author(s): Y., Sakawa, D., Watanabe, T., Shibahara, K., Sugiyama, T., Tanabe
  • Journal Title: J. Nucl. Mater 367-370 Pages: 1516-1521
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Distribution of hydrogen isotopes retained in the divertor tiles used in JT-60U (2007)
  • Author(s): Y., Hirohata, T., Tanabe, T., Shibahara, et. al.
  • Journal Title: J. Nucl. Mater. 367-370 Pages: 1260-1265
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] On the possibility of ITER starting with full carbon (2006)
  • Author(s): T.Tanabe
  • Journal Title: Fusion Engineering and Design 81 Pages: 139-147
  • Description: 「研究成果報告書概要(和文)」より
  • Peer Reviewed
• [Journal Article] Hydrogen isotope retention of JT-60U W-shaped divertor tiles exposed to DD discharges (2006)
  • Author(s): T.Shibahara, T.Tnabe, 他9名
  • Journal Title: J.Nucl.Mater 357 Pages: 115-125
  • Description: 「研究成果報告書概要(和文)」より
  • Peer Reviewed
• [Journal Article] Long-term erosion and re-deposition of carbon in the divertor region of JT-60U (2006)
  • Author(s): Y., Gotoh, T., Tanabe, Y., Ishimoto, K., Masaki, T., Arai, H., Kubo, K., Tsuzuki, N., Miya
  • Journal Title: J. Nucl. Mater 357 Pages: 115-125
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Hydrogen isotope retention of JT-60U W-shaped divertor tiles exposed to DD discharges (2006)
  • Author(s): T., Shibahara, T., Tanabe, Y., Hirobata, et. al.
  • Journal Title: J. Nucl. Mater. 357 Pages: 138-146
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Study of global wall saturation mechanisms in long-pulse ELMy H-mode discharges on JT-60U (2006)
  • Author(s): H., Takenaga, T., Nakano, N., Asakura, H., Kubo, S., Konoshima, K., Shimizu, K., Tsuzuki, K., Masaki, T., Tanabe, S., Ide, T., Fujita
  • Journal Title: J. Nucl. Fusion 46 Pages: S39-S48
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] On the possibility of ITER starting with full carbon, Tokyo, Fusion Eng. and Design, 81(2006)pp.139-147. (2006)
  • Author(s): T., Tanabe
  • Journal Title: Fusion Eng. and Design 81 Pages: 139-147
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Near-surface characterization of plasma-facing materials in a DT fusion reactor (2007)
  • Author(s): T., Tanabe
  • Organizer: 17th International Vacuum Congress
  • Place of Presentation: Stockhlom, Sweden
  • Year and Date: 20070602-06
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Tritium distribution measurement of JET Mk IIGB divertor tiles (2006)
  • Author(s): T., Tanabe, K., Sugiyama, T., Renvall, J., Likonen, J. P., Coad
  • Organizer: 17th Intern. Conf. on Plasma Surface Interactions
  • Place of Presentation: Hefei, China
  • Year and Date: 20060521-27
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Ion beam analysis of H/D retention on the near surface of JT-60U plasma facing wall tiles (2006)
  • Author(s): K., Sugiyama, T., Hayashi, K., Krieger, M., Mayer, K., Masaki, N., Miya , T., Tanabe
  • Organizer: 17th Intern. Conf. on Plasma Surface Interactions
  • Place of Presentation: Hefei, China
  • Year and Date: 20060521-27
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Modeling of Asymmetric Redeposition Distribution between Inner and Outer Regions of the W-shaped Divertor in JT-60U (2006)
  • Author(s): K., Ohya, K., Inai, T., Tanabe, H., Takenaga
  • Organizer: 17th Intern. Conf. on Plasma Surface Interactions
  • Place of Presentation: Hefei, China
  • Year and Date: 20060521-27
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Properties of hydrogen desorption from co-deposits on JT-60 graphite tile by pulsed laser ablation (2006)
  • Author(s): D., Watanabe, Y., Sakawa, T., Shibahara, K., Sugiyama, T., Shoji, K., Yamazaki, T. Tanabe
  • Organizer: 17th Intern. Conf. on Plasma Surface Interactions
  • Place of Presentation: Hefei, China
  • Year and Date: 20060521-27
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Near-surface characterization of plasma-facing materials in a DT fusi on reactor(招待講演) (2006)
  • Author(s): T.Tanabe
  • Organizer: 17th International Vacuum Congress
  • Place of Presentation: Stockhlom,Sweden
  • Year and Date: 2006-07-05
  • Description: 「研究成果報告書概要(和文)」より
• [Presentation] Pulsed-laser ablation of co-deposits on JT-60 graphite tile (2005)
  • Author(s): Y., Sakawa, D., Watanabe, T., Shibahara, K., Sugiyama, T., Tanabe
  • Organizer: 12th Intern. Conf. on Fusion Reactor Materials
  • Place of Presentation: Santa Babara
  • Year and Date: 20051204-10
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Tritium distribution measurement of the tile gap of JT-60U (2005)
  • Author(s): K., Sugiyama, T., Tanabe, K., Masaki, N., Miya
  • Organizer: 12th Intern. Conf. on , Fusion Reactor Materials
  • Place of Presentation: Santa Babara
  • Year and Date: 20051204-10
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Hydrogen Isotope Behavior in the First Wall of JT-60U after DD Discharge (2005)
  • Author(s): Y., Oya, T., Tanabe, M., Oyaidzu, T., Shibahara, K., Sugiyama, A., Yoshikawa, Y., Onishi, Y., Hirohata, Y., Ishimoto, J., Yagyu, T., Arai, K., Masaki, K., Okuno, N., Miya, S., Tanaka
  • Organizer: 12th Intern. Conf. on Fusion Reactor Materials
  • Place of Presentation: Santa Babara
  • Year and Date: 20051204-10
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Distribution of hydrogen isotopes retained in the divertor tiles used in JT-60U (2005)
  • Author(s): Y., Hirohata, T., Tanabe, T., Shibahara, M., Oyaizu, K., Sugiyama, Y., Oya, A., Yoshikawa, Y., Onishi, T., Arai, K., Masaki, Y., Ishimoto, K., Okuno, N., Miya
  • Organizer: 12th Intern. Conf. on Fusion Reactor Materials
  • Place of Presentation: Santa Babara
  • Year and Date: 20051204-10
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] High temperature irradiation damage of carbon materials studies by Laser Raman spectroscopy
  • Author(s): M., Yoshida, T., Tanabe, N., Ohno, M., Yoshimi, S., Takamura
  • Organizer: 13th Intern. Conf. on Fusion Reactor Materials
  • Place of Presentation: Niece, France
  • Year and Date: 00001210-14
  • Description: 「研究成果報告書概要(欧文)」より
• [Presentation] Hydrogen and hydrocarbon desorption from the deposited layer on JT-60 graphite tile by nano-second pulsed laser irradiation
  • Author(s): K., Sugiyama, Y., Sakawa, D., Watanabe, T., Tanabe, T., Shibahara, K., Masaki
  • Organizer: 13th Intern. Conf. on Fusion Reactor Materials
  • Place of Presentation: Niece, France
  • Year and Date: 00001210-14
  • Description: 「研究成果報告書概要(欧文)」より
• [Book] Proceedings of the 17th International Conference on Plasma-Surafce Interactions in Controlled Fusion Devices (2007)
  • Author(s): J.Li, X.Gao, J.Chen, T.Tanabe, P.GeHdrich, 他1名
  • Total Pages: 1479
  • Publisher: Elsevier
  • Description: 「研究成果報告書概要(和文)」より
• [Remarks] 「研究成果報告書概要(和文)」より
  • URL: http://www.qpn.kyushu-u.ac.jp/lab8/index-j.html