| Project/Area Number |
21K04260
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 22030:Geotechnical engineering-related
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| Research Institution | Waseda University |
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Principal Investigator |
Ito Daichi 早稲田大学, 理工学術院, 講師(任期付) (40875225)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Project Status |
Completed (Fiscal Year 2023)
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| Budget Amount *help |
¥4,160,000 (Direct Cost: ¥3,200,000、Indirect Cost: ¥960,000)
Fiscal Year 2023: ¥1,170,000 (Direct Cost: ¥900,000、Indirect Cost: ¥270,000)
Fiscal Year 2022: ¥1,300,000 (Direct Cost: ¥1,000,000、Indirect Cost: ¥300,000)
Fiscal Year 2021: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
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| Keywords | 放射性廃棄物処分 / ベントナイト / 水分移動特性 / 地下水質 / 膨潤 / 安全性評価 / 模型実験 |
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| Outline of Research at the Start |
本研究の目的は，各種放射性廃棄物処分施設において遮水材として用いられる，ベントナイトの水分移動特性における地下水質の影響を明らかにするためのデータベースと，コロイド化学や粘土科学的理論に基づく理論評価手法の構築である．また，処分場環境として想定される，排気条件や地下水圧等の境界条件が水分移動特性に及ぼす影響を明らかにし，処分施設設計や数値解析的安全評価に直接的に寄与するデータを取得する．
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| Outline of Final Research Achievements |
The purpose of this study is to develop a database for water migration characteristics of bentonite materials considering the effects of various groundwater quality, groundwater pressure, and exhaust conditions, which are essential for the safety assessment of radioactive waste disposal. The effects of ionic species present in seawater and groundwater on the infiltration properties of Na, Ca, and Ca-Mg bentonite with different exchangeable cation compositions were evaluated. In addition, water movement characteristics at unsaturated conditions were evaluated under increased water pressure up to 4 MPa, and it was confirmed that the water diffusion behavior was consistent and that no significant differences in water diffusion coefficients occurred. Finally, the effects of exhaust conditions on moisture migration behavior were evaluated, suggesting that the effects of pore air volume and air pressure should be considered.
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| Academic Significance and Societal Importance of the Research Achievements |
本研究で得られた成果は，各種放射性廃棄物処分のバリアシステムにおけるキーコンポーネントであるベントナイト系材料による遮水材の材料仕様決定に直接的に応用可能である．幅広い水質，水圧環境における水分移動特性を実験的に明らかにしており，処分施設の様々な立地条件や地層環境に応用可能な基礎的知見である．ゆえに，現在選定が進んでいて今後建設が想定される，地層処分施設をはじめとした各種放射性廃棄物処分施設のバリア材の仕様設計に貢献できる．
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