Hydrogen Transportation Behavior and its Control on the Water-Metal Boundary Using Pure Tritium
| Project/Area Number |
17560737
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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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 | Japan Atomic Energy Agency |
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Principal Investigator |
HAYASHI Takumi JAEA, Directorates of Fusion Energy Research, Principal Researcher (Principal Scientist), 核融合研究開発部門, 研究主幹 (70354678)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAMURA Hirofumi JAEA, Directorates of Fusion Energy Research, Assistant Principal Researcher (Senior Research Engineer), 核融合研究開発部門, 研究副主幹 (20354615)
ISOBE Kanetsugu JAEA, Directorates of Fusion Energy Research, Research Engineer, 核融合研究開発部門, 研究職 (00354613)
OKUNO Kenji Shizuoka Univ., Faculty of Science, Professor, 理学部, 教授 (80293596)
KOBAYASHI Kazuhiro JAEA, Directorates of Fusion Energy Research, Scientist, 核融合研究開発部門, 研究職 (40354609)
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| Project Period (FY) |
2005 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2006: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2005: ¥2,000,000 (Direct Cost: ¥2,000,000)
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| Keywords | Structural Material / Hydrogen Isotopes / Surface Characterization / Behavior Analysis / Tritium / Auto Radiography / Iron / Oxide layer / 界面・界面物性 / パラジウム |
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| Research Abstract |
In order to discuss detailed mechanism of hydrogen transferred from metal to water jacket at the water-metal boundary, a series of tritium permeation experiment has been performed at 423 K, using pure iron piping (4)10mm x 75mm^1 x 1mm^t) contained tritium gas (1 kPa, 7.4 GBq, >90% purity) under monitoring chemical species of tritium in the water jacket, which pressurized to 0.8MPa by He or 1%H_2 in He balance gases, by purging through ion chambers, water bubblers and oxidation catalyst bed. Surface of pure iron tube sample was mechanically polished initially. Also, samples with oxide layer, which grew in the water of 0.8MPa-He at 423K for more than 20 hours, were prepared. Sample surface was analyzed by SEM, XRD etc. The oxide layer consisted of inner fine part and outer porous part, and was magnetite (Fe_3O_4) not hematite (Fe_2O_3). The inner fine part of oxide grew 0.06~0.07 μm/h in the above condition. The main results are as follows
1. The permeation amount through pure iron to water jacket was about 1/5 of the calculated value in this experimental condition.
2. Even if surface oxide layer (fine and porous magnetite) grew, tritium permeation rate to water was not changed drastically.
3. However, HT fraction of permeated tritium was 30% initially, then, it decreased drastically to about 1/50 after > 1.4μm of fine magnetite layer growth. It suggested the relation between the HT fraction decrease and oxide layer growth.
4. Permeated species and amounts were not affected clearly by dissolved hydrogen amount difference between pure He and 1% H_2 in He balance purging under 0.8 MPa at 423 K.
From the above results, it suggests that the tritium in pure iron would transfer to water by isotope exchange reaction through surface hydroxyl species of magnetite. On the other hand, if surface hydroxyl density is small, the tritium would permeate to water as hydrogen gas after surface recombination.
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Report
(3 results)
Research Products
(3 results)
