| Project/Area Number |
17K14896
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| Research Category |
Grant-in-Aid for Young Scientists (B)
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| Allocation Type | Multi-year Fund |
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| Research Field |
Nuclear fusion studies
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| Research Institution | Kyoto University |
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Principal Investigator |
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| Project Period (FY) |
2017-04-01 – 2020-03-31
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| Project Status |
Completed (Fiscal Year 2019)
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| Budget Amount *help |
¥4,290,000 (Direct Cost: ¥3,300,000、Indirect Cost: ¥990,000)
Fiscal Year 2019: ¥780,000 (Direct Cost: ¥600,000、Indirect Cost: ¥180,000)
Fiscal Year 2018: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2017: ¥2,600,000 (Direct Cost: ¥2,000,000、Indirect Cost: ¥600,000)
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| Keywords | タングステン / 原子空孔 / 空孔-不純物複合体 / 照射損傷 / 陽電子消滅 / 第一原理計算 / 陽電子消滅分光法 / 陽電子寿命 / 結合エネルギー / 陽電子消滅ガンマ線ドップラー広がり / 格子欠陥 / 照射誘起欠陥 / 核融合 / プラズマ・壁相互作用 / 金属物性 / ナノ構造金属 / 希ガスプラズマ |
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| Outline of Final Research Achievements |
Vacancy-type defects formed by electron- or rare-gas-ion-irradiation and the differences in their development behaviors during the post-irradiation annealing process were investigated using positron annihilation spectroscopy. A comparison between helium- and neon-ion irradiated tungsten implied that the defect species are the same in both as-irradiated samples. However, in the case of neon-irradiated tungsten, in contrast to helium-ion irradiated one, the aggregation of vacancies and the formation of vacancy clusters were observed. Vacancy-hydrogen complexes were observed in tungsten irradiated with electrons in water, and the complexes began to dissociate from 623 K and formed vacancy clusters. In addition, when the sample purity was low, the formation of vacancy clusters was suppressed during the annealing process compared to the high-purity sample.
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| Academic Significance and Societal Importance of the Research Achievements |
核融合炉ではプラズマ冷却ガスとしてNeガスの導入が検討されているが，このようなHやHeよりも重いイオンの導入はプラズマ対向壁であるタングステンに，より重大な損傷を与える可能性が示された．一方で，原子空孔と大きな結合エネルギー持つ元素を意図的に添加することで，空孔集合体の形成を抑制し得る可能性も示された．
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