The central government is going ahead with a plan to use public funds in an attempt to stop radioactive water at the crippled Fukushima No. 1 nuclear power plant from flowing into the ocean, as operator Tokyo Electric Power Co. is seen as incapable of coping with the problem on its own.
"The problem of contaminated water is the most pressing. Rather than leave it up to TEPCO, the central government will come up with the measures to deal with it. The industry minister will instruct TEPCO in order to implement swift and multilayered measures," Prime Minister Shinzo Abe told a meeting of the Nuclear Emergency Response Headquarters on Aug. 7.
The Agency for Natural Resources and Energy released the results of a study that estimated about 1,000 tons of groundwater was flowing daily from nearby mountains to the ocean in the vicinity of the Fukushima No. 1 plant. Of that amount, about 400 tons is being contaminated with radiation after flowing into reactor buildings and other facilities at the plant site.
Of the remaining 600 tons of groundwater, about half was coming into contact with soil contaminated by radioactive materials around the reactor buildings and flowing into the ocean, according to the report.
Those involved in the study have been unable to determine when the contaminated water began flowing into the ocean. The possibility that contaminated water has been flowing into the ocean from the outset of the disaster cannot be denied.
The remaining 300 tons of groundwater is believed to be flowing into the ocean without being contaminated and poses no risk.
TEPCO plans to begin pumping up contaminated groundwater from wells on the plant site from Aug. 9. While about 100 tons will be pumped up daily at first, plans also call for digging more wells. The contaminated water will be stored in tanks on site.
According to TEPCO officials, tanks that have already been installed can hold about 380,000 tons. They are at the 320,000-ton mark now.
Plans call for installing tanks to increase the capacity to 700,000 tons by 2015 and 800,000 tons by fiscal 2016.
TEPCO officials hope to reduce the volume of contaminated groundwater to 60 tons a day and store that water in the tanks. One measure being considered for that reduction is to solidify contaminated soil with chemicals to construct a wall that would block out groundwater.
However, TEPCO plans do not take into consideration the possibility that contaminated water may leak from the reactor buildings.
Moreover, while the concentration of radioactive materials in the water is being measured at the wells, the results have fluctuated depending on the timing and location for the collection of the water samples. That makes it difficult to determine the level of radioactive materials in the water.
TEPCO officials have also been unable to determine where the water is leaking from, nor the extent of the area that has been contaminated.
Such uncertainty will likely force the utility to undertake a comprehensive review of measures that have been implemented until now to deal with the problem.
TEPCO also has an untested plan to freeze soil around the Fukushima No. 1 plant to block the flow of groundwater into the reactor and turbine buildings. However, because the project would cost several tens of billions of yen, TEPCO alone will be unable to finance it. The central government will cover part of the costs.
The Ministry of Economy, Trade and Industry plans to ask for funds in the fiscal 2014 budget for research purposes for the soil freezing project without specifying how much it wants.
The central government and TEPCO finalized the plan in May and are planning to complete the project by the first half of fiscal 2015.
Under the proposal, the wall of frozen soil will be built by inserting cooling pipes into the ground at intervals of about one meter around the buildings. The pipes would be inserted as deep as 30 meters into the ground. Coolant of about minus 50 degrees would be circulated through the pipes to freeze the surrounding soil.
Compared to constructing walls using clay or concrete, the frozen soil wall would better block the water and the time needed for completing the project would also be shorter.
TEPCO officials are confident they can surround all the buildings reasonably quickly.
One problem is that a huge amount of funds would be needed to continuously circulate the coolant.
In the meantime, TEPCO has other plans to construct a wall to block out water by injecting chemicals into the foundation near the levee to prevent contaminated water from flowing into the ocean. The utility will also pump up contaminated water.
However, those measures would not completely stop the flow of water into the ocean. An additional problem is where to store the pumped water.
If the water can be blocked from flowing into the reactor buildings, the contaminated water now accumulated in the basement of the buildings could be extracted to allow for the decommissioning of the reactors. However, the extraction of that water will likely be a difficult task because workers are unable to approach the buildings because of high levels of radiation.
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