Spatial distribution of radon and thoron in the soil around active faults as a contribution to the elevated indoor radon
| Project/Area Number |
21K12228
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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 63010:Environmental dynamic analysis-related
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| Research Institution | National Institutes for Quantum Science and Technology |
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Principal Investigator |
Janik Miroslaw 国立研究開発法人量子科学技術研究開発機構, 放射線医学研究所 計測・線量評価部, 研究員 (30833933)
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| Co-Investigator(Kenkyū-buntansha) |
小平 聡 国立研究開発法人量子科学技術研究開発機構, 放射線医学研究所 計測・線量評価部, グループリーダー (00434324)
ゴメス クリストファー 神戸大学, 海事科学研究科, 教授 (20800577)
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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: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2022: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
Fiscal Year 2021: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
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| Keywords | radon / thoron / active faults / carbon dioxide / permeability / modelling / active fault / radon transport / radon in soil |
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| Outline of Research at the Start |
Soil is a major source of the natural radioactive gases radon (Rn) and thoron (Tn). However, while proving very useful for monitoring faults and volcanic activity, Rn emissions can be severely detrimental to human health. Previous investigation of indoor Rn near Fugendake volcano showed elevated Rn concentration value. Since Rn elevation does not necessarily occur in all faults, and the mechanism of this enhancement is still debated, it seems reasonable to investigate how closely there is a relationship between Rn in soil near the tectonic faults and Rn exhaled at the surface.
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| Outline of Annual Research Achievements |
In our latest field study, the third ever, we confirmed the assumption of elevated radon and thoron concentrations in soil gases surrounding active fault zones. It is worth noting that our measurements revealed a strong correlation between carbon dioxide and radon and thoron concentrations. Conversely, the relationship between radon and permeability showed a weaker correlation.
In addition to field measurements, we also conducted comprehensive laboratory tests of soil samples, including analysis of radionuclide concentrations and various physicochemical parameters. These results were used as input parameters in the advection-diffusion model, enabling a detailed examination of how environmental factors influence radon transport and its subsequent infiltration into homes. The model was applied to multiple scenarios, focusing on typical Japanese house structures.
Our analysis revealed divergent trends between measurement sites. In one site, indoor radon concentrations were strongly influenced by changes in home construction, highlighting the importance of radon-resistant barriers. Conversely, at another site, indoor radon levels were primarily dictated by soil radon concentrations, highlighting the importance of local geological conditions.
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Report
(3 results)
Research Products
(4 results)
