Page 115 - Abstract book - TJSSF-2020

Thailand – Japan Student Science Fair 2020 (TJ-SSF 2020)
“Seeding Innovations through Fostering Thailand – Japan Youth Friendship”

Towards making insoluble the radioactive cesium in contaminated soil

Norino Sakata , Ren Matsubara
1
1
Advisors: Masahiro Takahashi , Hironori Ohashi
2
1

Fukushima High School
1
Fukushima University
2

Abstract

About 14 million cubic meters of removed soil generated by decontamination activities in Fukushima
will be finally disposed of. Discussions about disposal are proceeding on the premise that there is no
leakage of radioactive cesium, but when soil touches rainwater and seawater, the soil has a risk of
cesium leakage. Therefore, we focused on Pollucite, which is a type of zeolite. It is tough against pH
changes. However, the existence of leakage of radioactive cesium from the synthesized Pollucite has
not yet been verified. In this experiment, as a control experiment for our former experiment to confirm
the presence of leakage from Pollucite, we exposed the humus and soil to water and investigated the
presence of the leakage. As a result of the experiment, we were able to confirm the leakage of
radioactive cesium in both humus and soil. Furthermore, in all cases, hydrothermal synthesis of
Pollucite, a solution containing radioactive cesium, was generated as a waste liquid. To solve this
problem, the cyclic synthesis of Pollucite by reusing the waste liquid was devised, but research on the
optimum conditions at the time has not progressed. Therefore, we performed cyclic synthesis of
Pollucite by changing the amount of the content of the solution used for the synthesis, and investigated
the number of times the waste liquid can be reused. This time, we conducted the experiment by changing
the amount of CsCl. As a result, 7 was the maximum number. In addition, the number is considered to
change according to the pH concentration.

Keywords: Radioactive cesium, Pollucite, Leak test, Hydrothermal synthesis, Fukushima Daiichi
Nuclear Power Plant

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