Development of Cement System Barrier Generating Self-confinement Function of Nuclide in a Saturated Groundwater Flow Field
| Project/Area Number |
17H01371
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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 engineering
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| Research Institution | Tohoku University |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
桐島 陽 東北大学, 多元物質科学研究所, 教授 (00400424)
千田 太詩 東北大学, 工学研究科, 講師 (30415880)
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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 |
¥44,590,000 (Direct Cost: ¥34,300,000、Indirect Cost: ¥10,290,000)
Fiscal Year 2019: ¥6,370,000 (Direct Cost: ¥4,900,000、Indirect Cost: ¥1,470,000)
Fiscal Year 2018: ¥15,340,000 (Direct Cost: ¥11,800,000、Indirect Cost: ¥3,540,000)
Fiscal Year 2017: ¥22,880,000 (Direct Cost: ¥17,600,000、Indirect Cost: ¥5,280,000)
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| Keywords | 原子力エネルギー / バックエンド / 放射性廃棄物 / 地下管理・処分システム / セメント系材料 / 地下冠水環境 / カルシウムシリケート水和物 / ヨウ素 |
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| Outline of Final Research Achievements |
A cement-based barrier that retards the leakage of nuclides from the underground disposal facility for radioactive waste in a saturated flow-field with groundwater was developed in this study. The experimental data showed that calcium silicate hydrate (hereinafter referred to as the CSH gels) forms as a secondary mineral under a highly alkaline and flow condition, due to the elution of calcium ions from the cement necessary for the construction of the repository and the dissolution of silicic acid from the groundwater flow-paths. Besides it was figured out that the CSH gels lead a confinement function against iodide and iodate ions which is ten times or more than that conventionally assigned, because of both the decrease in the permeability of groundwater associated with the formation of the CSH gels and the chemical reactions. Moreover, the addition of hydrotalcite (HT) as a fine aggregate of cement can further improve their confinement effect under a freshwater groundwater condition.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究成果の学術的意義は、CSHが地下の冠水環境のような自由水を多く含む環境において二次鉱物として流動場に生成し、地下水の浸透性を抑え、CSHの安定化によるヨウ素との化学的な相互作用を明らかにしたことにある。その社会的意義は、本研究成果が地下冠水環境における放射性廃棄物の管理・処分システムの核種閉じ込めに大きく寄与する点にある。ヨウ素(I)の中でI-129は1,570万年の半減期を持ち、これまで地下水による移行を如何に抑えるかが課題であった。本成果では、二次鉱物のCSHがその閉じ込め性を有することに加えて、処分施設の建設時に用いるセメントの細骨材の選択とその有用性の整理にも貢献する。
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Report
(4 results)
Research Products
(36 results)
