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Thursday, 7 August 2014

Decontaminated water from Fukushima plant to be dumped into sea

Tokyo Electric Power Co. wants to dump decontaminated water from the Fukushima No. 1 nuclear power plant into the ocean.

Frustrated at past efforts to deal with this vexing problem, the company is in talks with government ministries to pump contaminated water found around the buildings on the plant site, process it to remove the radioactive materials and then release it into the Pacific Ocean.

TEPCO has also presented an outline of the plan to the Fukushima Prefectural Federation of Fisheries Cooperative Associations. A federation official said officials of the central government and TEPCO will visit local fisheries cooperatives to explain the plan.

"We would never consider dumping the water into the ocean unless we received the consent of local residents," a TEPCO official said.

The proposal is designed to reduce the volume of groundwater that is flowing into buildings that already hold contaminated water.

The plan would involve wells called subdrains that have been built around buildings on the plant site.
Before the 2011 Fukushima nuclear accident, the subdrains were used to pump out groundwater and dump it into the ocean as a means to lower the groundwater level.

But after the Great East Japan Earthquake in March 2011, the subdrains became unusable because the pumps were damaged and the groundwater had become contaminated with radioactive materials.
The daily flow of groundwater into the plant buildings is what's causing 400 tons of contaminated water to be generated on a daily basis.

TEPCO officials plan to use the existing 27 subdrain wells and dig 15 additional wells to reduce the volume of contaminated water created to around 200 tons a day, or half the present level.

Processing equipment would be used to remove the radioactive cesium and strontium in the groundwater before the water is released into the sea.

The utility is seeking to begin the new process this autumn and has submitted a request for screening the processing equipment with the Nuclear Regulation Authority.

If the plan is approved, it would be the first time since the Fukushima nuclear accident for contaminated water to be dumped into the ocean after it has been purified.

Although TEPCO will seek the consent of local residents and fisheries cooperatives, a high-ranking official with a Fukushima fisheries cooperative said the utility may face an uphill road in gaining approval.

"The water close to the plant buildings is already contaminated," the official said. "Fishermen are sure to raise objections to the plan so it will be difficult to gain their understanding."

In May, TEPCO began pumping out groundwater from the mountain side of the plant and dumping it into the ocean. This was done to prevent the water reaching the plant and becoming contaminated.
The company is now constructing an underground frozen soil wall to stop groundwater from reaching the plant.
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