Self-restoration function of natural barrier confining radionuclides by clogging flow-paths with the redistribution of silicic acid
| Project/Area Number |
18H01910
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Review Section |
Basic Section 31010:Nuclear engineering-related
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
Chida Taiji 東北大学, 工学研究科, 准教授 (30415880)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
新堀 雄一 東北大学, 工学研究科, 教授 (90180562)
関 亜美 東北大学, 工学研究科, 助教 (80912328)
|
|---|
| Project Period (FY) |
2018-04-01 – 2022-03-31
|
| Project Status |
Completed (Fiscal Year 2021)
|
| Budget Amount *help |
¥17,420,000 (Direct Cost: ¥13,400,000、Indirect Cost: ¥4,020,000)
Fiscal Year 2021: ¥2,860,000 (Direct Cost: ¥2,200,000、Indirect Cost: ¥660,000)
Fiscal Year 2020: ¥3,120,000 (Direct Cost: ¥2,400,000、Indirect Cost: ¥720,000)
Fiscal Year 2019: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
Fiscal Year 2018: ¥7,930,000 (Direct Cost: ¥6,100,000、Indirect Cost: ¥1,830,000)
|
|---|
| Keywords | ケイ酸 / 析出 / コロイド / セメント系材料 / 処分システム / バックエンド / 放射性廃棄物 / 原子力 / 核種閉じ込め / 放射性廃棄物処分 / 天然バリア / 核種移行 |
|---|
| Outline of Final Research Achievements |
Spatial redistribution of silicic acid occurs around a radioactive waste repository, due to dissolution and deposition with the change of pH. This study focused on the self-restoration of the confinement for radionuclides in the host rock caused by the redistribution of silicic acid, especially deposition behavior. The experimental results showed that the deposition rates of silicic acid are on the same order of magnitude under all conditions in this study, i.e., the conditions using amorphous silica and hydrothermally-altered minerals as the solid phase for the deposition of silicic acid and coexisting various multivalent cations in groundwater. Furthermore, the analysis based on the estimated deposition rates suggests that the deposition of silicic acid in the groundwater flow-field can retard the migration of nuclides because of narrowing flow-paths in the host rock.
|
| Academic Significance and Societal Importance of the Research Achievements |
本研究の学術的意義は，地下環境に想定される多様な鉱物および共存イオン条件において概ね同様の析出速度でケイ酸が析出することを明らかにした点にある．一方，放射性廃棄物処分システムの性能評価において，セメント系材料の利用に起因した処分場周辺のpH変動により，岩盤が溶解して流路が拡張され，核種が移行しやすくなるという懸念があった．そのため，本研究で整理されたケイ酸の析出による岩盤の核種閉じ込め効果の自己修復を示したことは，処分システムの頑健性および信頼性の向上に貢献するという点において社会的意義がある．
|
Report
(5 results)
Research Products
(26 results)
