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information about Fukushima published in English in Japanese media info publiée en anglais dans la presse japonaise

TEPCO & icewall problems

July 7, 2014
TEPCO plan to block contaminated water with ice walls hits snag 



A plan by Tokyo Electric Power Co. (TEPCO) to block the flow of contaminated water at the Fukushima No. 1 Nuclear Power Plant faces problems as ice walls meant to stop the flow have failed to form.

The TEPCO plan was to use tubes of coolant to freeze the water around the connecting points between the No. 2 and No. 3 reactors' turbine buildings and underground trenches, stopping the flow of water at these points and allowing workers to remove around 11,000 tons of contaminated water from the trenches, which are further down the flow. TEPCO began work to install 17 coolant tubes this April and planned to create the ice walls in mid-June and start removing the trench water in mid-July. However, come July the ice walls had not formed.

If the contaminated water is not removed from the trenches it could leak out from them. Furthermore, the continued presence of the water will prevent the creation of outer ice walls encircling the No. 1 through No. 4 reactors, which are a central part of TEPCO's plans to cut down on contaminated water at the plant.

The trenches are about five meters wide and five meters tall, and run around 22 meters underground. TEPCO speculates that the reason the ice walls have failed to form is that "contaminated water flows back and forth between the turbine buildings and the trenches." The utility will add two more coolant tubes, but whether this will solve the issue is unclear.

However, TEPCO remains optimistic, saying, "The construction of the outer ice wall toward the ocean is scheduled for October or later, so there is time." But Toyoshi Fuketa, a member of the Nuclear Regulation Authority, says, "The contaminated water in the trenches is the risk factor of greatest concern at the Fukushima No. 1 Nuclear Power Plant. If the flow of water cannot be stopped, there is no point in talking about ice walls."


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