Fukushima N-plant’s impermeable wall is one way to revive local fisheries — The Yomiuri Shimbun

The Yomiuri Shimbun presents an optimistic and rather conservative article on the contaminated water situation at Fukushima No. 1.

” At the port area in front of Tokyo Electric Power Co.’s Fukushima No.1 nuclear power plant, radioactive concentration levels have begun to drastically decrease.

This is because an impermeable wall has been completed that runs along the revetment of the port. This means the risk of contaminated groundwater leaking into the port area has been reduced to nearly zero. Countermeasures against contaminated water have steadily been making progress.

Concentration levels of radioactive substances in the sea outside the port area have now fallen to within the government-set standards for acceptable drinking water. At spots close to the port revetment, concentration levels of all kinds of radioactive substances have also been falling markedly since the completion of the impermeable wall.

These developments will probably be conducive to helping reinvigorate the local fisheries industry, which has been afflicted with harmful rumors. Having confirmed firsthand the effectiveness of the impermeable wall, a representative of the local fisheries industry reportedly called on TEPCO to “inform the public of the current state of things.”

Although the crisis at the Fukushima nuclear plant has had little impact on marine products in the waters near the facility, fishing operations along the coastal areas of Fukushima Prefecture have been conducted only on an experimental basis. Both the government and TEPCO must disseminate information, both at home and abroad, regarding the progress of radiation countermeasures and the improvement of water quality.

Construction work for the impermeable wall commenced in 2012. There were fears, however, that the revetment would leave groundwater with nowhere to go when it was sealed off completely, and it would eventually overflow. The impermeable wall project was suspended, and a section measuring about 10 meters was left unsealed.

So many water tanks

When it became possible in September this year to drain groundwater into the sea after pumping and purifying it, the open section of the wall was sealed.

Although an end to the problem of radioactive material leaking into the sea is now in sight, there are still a number of tasks that must be addressed in dealing with contaminated water. In particular, no time must be wasted in devising measures to effectively cope with events such as heavy rain.

There have been instances of radioactive substances within the plant’s premises mixing with rainwater and flowing into the sea via its drainage system. In the reactor buildings, traces and residue of radioactive substances are still present in many places. Decontamination efforts should be redoubled and sufficient attention paid to ensuring the safety of the workers involved.

Operations to deal with groundwater flowing into the reactor buildings are only half complete. The volume of inflowing groundwater has increased, at times even now, to nearly 400 tons a day. Given that this water is contaminated with radioactive substances, it is of key importance to work out what should be done to reduce it.

An underground bypass is already in place that pumps groundwater before it may be contaminated and drains it into the sea.

Work on building underground walls made of frozen soil around the reactor buildings to block the inflow of groundwater has also been undertaken. After completion of the walls, the inflow of groundwater is expected to decrease to less than 100 tons per day. This work must proceed steadily.

What should be of concern is that the plant’s premises is being crammed with an increasing number of tanks to store purified water. Sooner or later, it will certainly become difficult to secure space for the tanks.

It is considered realistic to drain the purified water into the sea just as other nuclear-related facilities have been doing so. ”



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