Title: Emission of spherical cesium-bearing particles from an early stage of the Fukushima nuclear accident
Source: Scientific Reports (Nature Publishing Group)
Authors: Kouji Adachi, Mizuo Kajino, Yuji Zaizen & Yasuhito Igarashi
Date Published: Aug. 30, 2013
The Fukushima nuclear accident released radioactive materials into the environment over the entire Northern Hemisphere […] we still do not know the exact physical and chemical properties of the radioactive materials. This study directly observed spherical Cs-bearing particles emitted during a relatively early stage (March 14-15) of the accident. In contrast to the Cs-bearing radioactive materials that are currently assumed, these particles are larger, contain Fe, Zn, and Cs, and are water insoluble. Our simulation indicates that the spherical Cs-bearing particles mainly fell onto the ground by dry deposition. The finding of the spherical Cs particles will be a key to understand the processes of the accident and to accurately evaluate the health impacts and the residence time in the environment.
[…] Although the accident has global impacts, we still do not know exactly what happened in the reactors during the accident […]
We measured the radioactive materials that were collected in the filter at ground level on March 14-15 […] we counted approximately 100 spots caused by radioactive materials, suggesting a concentration of approximately 10 radioactive particles per m³. […]
This study reports for the first time the presence of spherical radioactive Cs-bearing particles emitted from the FNPP during a relatively early stage (March 14-15) of the accident. The particles coexist with Fe, Zn, and possibly other elements, and their diameters are approximately 2 μm. Because these elements were evenly distributed within the particle, we conclude that they are internally mixed and form an alloy. […] Due to its spherical shape and composition, the particle is likely solid and is largely insoluble in water. […]
The spherical Cs-bearing particles likely have longer retention times on the land surface than those of the water-soluble Cs particles. The retention time of the particles in the soil or other environments needs to be reconsidered.
Published: October 24th, 2013 at 8:55 am ET