Removal of Contaminated Water from Seawater Piping Trench

After the accident, highly contaminated water accumulated inside the seawater piping trench, an underground tunnel originally for storing pipes and cables, on the ocean side of the Unit 2 to Unit 4 turbine buildings. This contaminated water was removed from the trench by transferring it to the turbine buildings or elsewhere, considering the nature of the contamination and the quality and volumes of water. The trench was then filled by suitable methods, selecting filling materials in consideration of the structure and other factors, to mitigate leakage risks.