TEPCO to build seawater containment wall off Fukushima plant

Tokyo Electric Power Co. will install an 800-meter-long wall off crippled Fukushima No. 1 nuclear power plant to prevent radioactive groundwater from flowing into the sea.

The wall will be completed in two years after construction begins between mid-October and mid-January, ahead of the initial schedule, TEPCO officials said Aug. 1.

Steel plates will be set up several meters off the existing shore protection, and the area inside the new perimeter will be reclaimed.

The wall will be sunk about 30 meters deep through the permeable strata--where groundwater flows--to the bedrock below.

TEPCO at first planned to begin construction after Step II of its road map to bring the nuclear crisis under control ends in January.

But the company decided to advance the schedule to ease concerns among foreign countries and fishery officials about contaminated groundwater flowing into the sea.

Construction costs will be announced by mid-August.

"Surveys of groundwater and other data show there is a low possibility that radioactive water is leaking into the sea," said Junichi Matsumoto, acting general manager of TEPCO's Nuclear Power and Plant Siting Division. "But we decided to install the wall because we cannot rule out that possibility."

TEPCO is considering whether it should eventually install steel plates on the other side of the plant to surround the four reactors where explosions occurred.

The company plans to investigate designs and construction methods for the ground-side wall before Step II ends.

Highly radioactive water accumulated at the plant flowed into the sea in March and May through trenches for workers and damaged parts of piping for electric wiring.

TEPCO has filled the trenches with concrete. It has also installed curtain-like screens called silt fences and steel plates around seawater intakes for the reactors to prevent contaminated water from leaking into the sea.