1994 Fiscal Year Final Research Report Summary
EXPERIMENTAL STUDY ON HYDROGEN SUPER-PERMEATION IN A LARGE PLASMA DEVICE
| Project/Area Number |
04452326
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Nuclear engineering
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
HIGASHI Kunio Kyoto University Dept.Nucl.Engng., Professor, 工学部, 教授 (30026017)
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| Co-Investigator(Kenkyū-buntansha) |
SHIN Kazuo Kyoto University Dept.Nucl.Engng., Associate Prof., 工学部, 助教授 (70109023)
FUJITA Haruyuki Kyoto University Dept.Nucl.Engng., Assistant Prof., 工学部, 助手 (90026039)
ZUSHI Hideki Kyoto University Plasma Phys.Lab., Associate Prof., ヘリオトロン核融合研究センター, 助教授 (20127096)
TAKAGI Ikuji Kyoto University Dept.Nucl.Engng., Associate Prof., 工学部, 助教授 (20206717)
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| Project Period (FY) |
1992 – 1994
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| Keywords | HELIOTRON E / PERMEATION / HYDROGEN ISOTOPE / TRAPPING / RADIATION DAMAGE / INVENTORY / PLASMA-FACING MATERIAL / PLASMA-DRIVEN PERMEATION |
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| Research Abstract |
Super-permeation is one of the characteristic behaviors of hydrogen isotopes in Plasma-facing materials. It would cause a significant leakage of tritium out of the system in fusion reactors. Another is the hydrogen trapping in radiation damage, which would increase the tritium inventory. In the present work, experimental studies on the super-permeation and the hydrogen trapping in the plasma-facing materials were performed.
The super-permeation phenomena was observed in Heliotron E,a large plasma device, during discharge cleanings. The result suggested that hydrogen recycling was very active and the permeation flux represented the progress of the discharge cleaning. A small plasma device was used to simulate pulse operations for large plasma devices. It was found that the permeation rate at the transient state could be well estimated by numerical calculations.
In order to investigate the radiation-induced traps for hydrogen isotopes, depth profiles of deuterium in metal samples were observed using the nuclear reaction analysis (NRA). The samples were bombarded with ions in advance and faced to deuterium plasma during the NRA.The result showed that the deuterium trapping was related to the atomic displacement. Applying a model, which was proposed in the present work, the activation energy and the production rate of the trapping site were quantitatively evaluated.
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