Radioactive caesium was released during the accident of Fukushima Dai-ichi nuclear power plant (FDNPP) into the surrounding environment. In the current work, radiocaesium micro-particles (CsMPs) and radiocaesium-rich soil particles were selectively separated from soil particles as well as from each other using autoradiography-based procedure. The applied separation scheme is based on water dilution followed by drying of the soil sample prior to imaging plate autoradiography. The SEM/EDS investigation of the individual CsMPs showed that these particles have a silicate glass structure and vary in shape with a diameter less than 10 μm. For the first time, a two-stage formation mechanism was suggested for a CsMP based on shape and structure heterogeneity of its two parts. Perfect spherical core might be formed in the first stage with a remarkable lower content of Al, and relatively higher concentrations of Si and K than an outer angulated structure, which might be attached to the core sphere during a late stage.

The radiocaesium-rich soil particles have bigger size than CsMPs and have a plate-like structure with cleavages inside the grains, which suggest that these particles might be a weathered biotite. The average radioactivity ratio of ¹³⁴Cs/¹³⁷Cs (dated March 11, 2011) in the investigated particles was found to be 1.05 ± 0.01, which confirmed that the radiocaesium in CsMPs and in the contaminated soil particles has the same source of origin, which could be unite 3 of FDNPP.

福岛第一核电站（FDNPP）发生事故时，放射性铯被释放到周围环境中。在当前的工作中，使用基于放射自显影的方法选择性地将放射性铯微粒（CsMP）和富含放射性铯的土壤颗粒与土壤颗粒以及彼此分离。应用的分离方案基于水稀释，然后在对板进行放射自显影之前对土壤样品进行干燥。单个CsMP的SEM / EDS研究表明，这些颗粒具有硅酸盐玻璃结构，并且形状变化，直径小于10μm。首次提出了基于CsMP两部分形状和结构异质性的两阶段形成机理。

富含放射性铯的土壤颗粒尺寸比CsMPs大，并且具有板状结构，颗粒内部有裂隙，这表明这些颗粒可能是风化的黑云母。被调查颗粒的平均放射性比为¹³⁴ Cs / ¹³⁷ Cs（日期为2011年3月11日）为1.05±0.01，这证实了CsMPs和受污染的土壤颗粒中的放射性铯具有相同的来源，可以是FDNPP的3。