Study of the existence form of radioactive cesium -In the case of fine particles collected from the suburbs of FDNPP-

2019 Fiscal Year Final Research Report

• Project/Area Number: 17K00545
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Risk sciences of radiation and chemicals
• Research Institution: Fukushima University
• Principal Investigator: Takase Tsugiko 福島大学, 共生システム理工学類, 特任准教授 (10466641)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: 放射性セシウム / 構造解析 / 計算化学

Outline of Final Research Achievements

In this study, we targeted on the fine particles containing radioactive Cs collected from the surface of the FDNPP area. The local area in the particles were analyzed using a local structure analysis system consisting of Focused Ion Beam machine (FIB) and Scanning transmission Electron microscope (STEM: Energy dispersive X-ray analyzer was built in STEM).
It was clarified that weathered biotite particles containing radioactive Cs are heterogeneous structures in which biotite-like and vermiculite-like structures are mixed. In addition, by modeling the structural characteristics of particles and performing simulations based on computational chemistry, It was suggested radioactive Cs ion is adsorbed to K-ion site in weathered biotite particles, which stabilizes Cs ion in the particles.

Free Research Field

構造化学

Academic Significance and Societal Importance of the Research Achievements

本研究では，福島第一原子力発電所近郊で採取した放射性Csを含む土壌粒子の微視的な構造解析を行い，構造解析データに基づく量子化学シミュレーションと融合することにより，土壌粒子の「biotite-likeとVermiculite-likeな構造が混在したheterogeneousな構造」が放射性Csの吸着に大きな影響を及ぼすことを明らかにし，福島原発事故によって大気中に放出された放射性Csの吸着過程に関する新たな知見を得ることができた．