| Project/Area Number |
11308016
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Nuclear fusion studies
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| Research Institution | Natiomal Institute for Fusion Science |
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Principal Investigator |
NAKAMURA Yukio Natiomal Institute for Fusion Science Department of Large Helical Device Project, Professor, 大型ヘリカル研究部, 教授 (40136560)
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| Co-Investigator(Kenkyū-buntansha) |
MORISAKI Tomohiro Natiomal Institute for Fusion Science Department of Large Helical Device Project,Research Associate, 大型ヘリカル研究部, 助手 (60280591)
MASUZAKI Suguru Natiomal Institute for Fusion Science Department of Large Helical Device Project,Research Associate, 大型ヘリカル研究部, 助手 (80280593)
SUZUKI Hajime Natiomal Institute for Fusion Science Department of Large Helical Device Project,Research Associate, 大型ヘリカル研究部, 助手 (20260044)
OHYABU Nobuyoshi Natiomal Institute for Fusion Science Department of Large Helical Device Project,Professor, 大型ヘリカル研究部, 教授 (60203949)
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| Project Period (FY) |
1999 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥15,450,000 (Direct Cost: ¥13,500,000、Indirect Cost: ¥1,950,000)
Fiscal Year 2001: ¥8,450,000 (Direct Cost: ¥6,500,000、Indirect Cost: ¥1,950,000)
Fiscal Year 2000: ¥7,000,000 (Direct Cost: ¥7,000,000)
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| Keywords | Divertor Pumping / Neutrl Particle Control / Membrane Pumping / Selective Pumping of Hydrogen / Absorption and Retention of Hydrogen / 不純物堆積効果 / メンブレンパネル |
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| Research Abstract |
For the purpose of producing a steady-state high-temperature plasma, a new particle control system must be developed for decreasing neutral pressure at the peripheral region. In order to make a research on the application of membrane pumping to nuclear fusion devices, we made a membrane test device with a large vacuum tank (600φ, 1000L). Then we could carry out various experiments on membrane pumping. By combining the test device with the previous membrane device, the effect of impurity deposition onto the membrane surface on hydrogen permeation through niobium membrane was investigated and it was found that the permeability decreased with increasing the impurity deposition. Moreover, it was also found that the deposited impurities were resolved into the bulk of membrane by heating the membrane up to the high temperature (〜1200℃) and the permeability could be recovered to the previous one. In the study of membrane properties at the room temperature by using an ECR plasma source, the sp
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eed of hydrogen permeation through the membrane extremely decreased with decreasing the membrane temperature. As a result, it was found that it was very important to make a large asymmetry of potential barrier due to nonmetal impurity on the membrane surface at the inside and outside of the membrane. In the final fiscal year, we designed a niobium absorption panel as the pumping system for the large helical device (LHD) and performed the performance test using a prototype absorption panel, which was installed into LHD. The niobium panel at the room temperature absorbed hydrogen atoms produced by an atomizer and the strong ability of hydrogen absorption (120 Pam^3/s) was demonstrated without the reemission of absorbed hydrogen. The capability of hydrogen absorption was about 7 x 10^19 cm^-2 s^-1. Moreover, we obtained the recombination coefficient of hydrogen on the panel surface experimentally and it enabled us to estimate the performance of niobium panel as a pumping system more exactly. This result is very useful for designing a panel pump for nuclear fusion devices in future. This panel was indeed installed into LHD and the absorption of hydrogen atoms produced during plasma experiment was demonstrated. It is a successful result to demonstrate the applicability of niobium panel to the real fusion device. Less
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