Sea-side impermeable wall

The seaside impermeable wall is an underground wall constructed along the coastline to hold back groundwater flowing from the premises alongside Units 1 to 4 into the port area at Fukushima Daiichi Nuclear Power Station. This groundwater may have come into contact with some radioactive materials already in the ground since the accident but is not nearly as contaminated as the retained water inside the reactor buildings. The accumulated water behind the wall is pumped up, treated, and discharged into the port area by the Subdrain systems.

Starting from April 2012, the construction of the seaside impermeable wall was finally completed on October 26, 2015. The wall is composed of 594 steel pipe sheet-piles driven into the earth across a width of about 780 meters. In case of any contaminated water leakage, it is expected to significantly reduce the risk of groundwater flowing into the ocean. The completion of the wall marks major progress in TEPCO's multi-faceted strategy to manage water during decommissioning. Close monitoring of the port area will continue.