1994 Fiscal Year Final Research Report Summary
MICRISTRUCTURAL PROCESSES OF PLASMA INJECTION EFFECTS IN FUSION PLASMA-FACING MATERIALS
| Project/Area Number |
05680436
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Nuclear fusion studies
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
MUROGA Takeo KYUSHU UNIVERSITY,Research Institute for Applied Mechanics, Asoociate Professor, 応用力学研究所, 助教授 (60174322)
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| Co-Investigator(Kenkyū-buntansha) |
TOKUNAGA Kazutoshi KYUSHU UNIVERSITY,Research Institute fo Applied Mechanics, Research Associates, 応用力学研究所, 助手 (40227583)
WATANABE Hideo KYUSHU UNIVERSITY,Research Institute for Applied Mechanics, Research Associates, 応用力学研究所, 助手 (90212323)
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| Project Period (FY) |
1993 – 1994
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| Keywords | Plasma-Facing Material / Tungsten / Molybdenum / Hydrogen / Radiation Effect |
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| Research Abstract |
In-situ observations of microstructural evolution in molybdenum and tungsten were carried out during irradiation with low energy hydrogen ions for the purpose of investigating the effect of plasma-particle injection to plasma-facing components of fusion reactors. A strong dependence of microstructural evolution on the ion energy was observed in molybdenum. Loop generation, growth, tangling and the resulting network formation were observed with ions of 4ke V and above. On the other hand hydrogen clusters were observed at 2keV and below. In tungsten, however, no remarkable microstructural evolution was observed at 2keV and below. Comparisons were made between the microstructural evolution during post-irradiation annealing and gas desorption spectrometry during annealing. The escape of dislocation loops at the surfaces occuured in tungsten during the oppst-irradiation annealing. The peak temperature observed during the thermal desorption spectrometry corresponded well with that where the loop escape took place. This fact suggests that hydrogen trapped at the loops or nearby matrices escaped out of the surfaces together with the loops. The comparison was made between the high-purity and the low-purity tungsten. The loops formed in the low-purity tungsten were more stable, resistant against the slipping to the surfaces. The hudrogen retention was found to be high in the low purity tungsten relative to that in the high purity one. Thus it is needed to examine the high Z metallic materials considering their fabrication processes, i. e. impurity level for use as plasma-facing materials.
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