2022 Fiscal Year Final Research Report
Influences of natural organic matters altering cementitious materials to the safety of radioactive waste disposal
| Project/Area Number |
21K20348
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| Research Category |
Grant-in-Aid for Research Activity Start-up
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| Allocation Type | Multi-year Fund |
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| Review Section |
0202:Condensed matter physics, plasma science, nuclear engineering, earth resources engineering, energy engineering, and related fields
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| Research Institution | The University of Tokyo |
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Principal Investigator |
Toda Kanako 東京大学, 大学院工学系研究科(工学部), 助教 (00908387)
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| Project Period (FY) |
2021-08-30 – 2023-03-31
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| Keywords | セメント系材料 / C-S-H / M-S-H / N-A-S-H / 天然有機物 |
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| Outline of Final Research Achievements |
This study evaluated the contribution of natural organic matter (NOM) to the structures of C-S-H, M-S-H, and N-A-S-H which are silicate hydrates with Ca, Mg, and Na cations, respectively, by synthesis experiments of those phases in coexistence of model NOM. Also, NOM's diffusion to those silicate hydrates were evaluated by batch alteration experiments. These silicate hydrates are matrices of construction material candidates in deep geological disposal sites, which could be altered by NOMs dissolved in groundwater, hence influence the radionuclide (RI) sorption capacity. This study suggested the possibility of alteration on Si polymerization states of C-S-H and M-S-H by model NOM. It was also suggested that NOM may sorb and diffuse to all silicate hydrates. Overall, NOMs may change the RI sorption capacity of those silicate hydrates. N-A-S-H was suggested as most resistant to the alteration of the structure followed by M-S-H then C-S-H, C-S-H being the most vulnerable to the alteration.
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| Free Research Field |
応用鉱物学、セメント化学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究結果の学術的意義は、不定形の高分子である天然有機物と低結晶性の鉱物の相互作用を明らかにしようとする点にある。現代の技術では分析が困難な複合試料であるが、天然で生じうる現象のため、この新たな研究領域の開拓は、天然有機物-セメント系材料-放射性核種間作用の理解を推進する研究の前章と位置付けられる。 社会的意義は、放射性廃棄物処分場で実際に起こりうる天然有機物による建設材料マトリックスの変質を明らかにすることで、現場施工に適した建設材料の判断基準の一つとして活用することが想定でき、その安全性向上に資することができる。
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