Study of radon emanation with a focus on internal properties

2020 Fiscal Year Final Research Report

• Project/Area Number: 18K05209
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 34030:Green sustainable chemistry and environmental chemistry-related
• Research Institution: Japan Atomic Energy Agency
• Principal Investigator: Sakoda Akihiro 国立研究開発法人日本原子力研究開発機構, 核燃料・バックエンド研究開発部門 人形峠環境技術センター, 研究職 (50603221)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: ラドン / トロン / 散逸 / 鉱物

Outline of Final Research Achievements

Radon (Rn-222) and thoron (Rn-220) are natural radioactive inert gases, originating from radium in solids such as minerals. Since they exist everywhere, various research efforts have been made from the viewpoint of health effects and tracer use. To better understand radon and thoron emanation phenomenon, which is the first process of their environmental dynamics, the present study discussed it experimentally and numerically in light of the effects of properties of mineral particles. The heating treatment of powdered mineral samples (400 to 800°C for 6 hours) suppressed the emanation power of both radon and thoron due to the annealing effect. The model calculation also found that the contribution of solid diffusion to the emanation was much smaller than that of alpha recoil.

Free Research Field

環境放射能

Academic Significance and Societal Importance of the Research Achievements

ラドン・トロン散逸の理解の深化によって、環境動態の最初のプロセスである「発生」の特徴が明らかになり、環境影響評価の向上による放射線防護分野への貢献が考えられる。また、ラドンを境界とした鉱物中の放射非平衡の理解にも貢献し、年代測定の精度向上など地球科学分野への貢献も考えられる。