A review of efforts for volume reduction of contaminated soil in the ten years after the accident at the Fukushima Daiichi Nuclear Power Plant

The accident at the Fukushima Daiichi Nuclear Power Plant in 2011 released many radioactive elements into the environment, contaminating a large amount of soil. Currently, 14 million m³ of contaminated soil is scheduled for interim storage, and the final disposal of the soil is planned by 2045. In the future, the decommissioning of the plant will generate a great amount of radioactive waste. Therefore, reduction of the volume of contaminated soil, which accounts for ~90% of the wastes, is a problem that needs to be addressed in parallel with the decommissioning of the plant. Since most of the radionuclides have decayed in the decade since the accident, radioactive Cs (especially ¹³⁷Cs) is one element that needs to be removed from the wastes. This review summarizes the progress of volume reduction technology for soil contaminated with radioactive Cs and an understanding of the existence of radioactive Cs in the soil.