” The volume of contaminated water continues to increase at Tokyo Electric Power Company Holdings Inc.’s Fukushima No. 1 nuclear power plant. Efforts to deal with this problem must be reinforced.
TEPCO has compiled a new set of measures to deal with the radioactive water. The steps are aimed at reducing to nearly zero the contaminated water inside reactor buildings, the prime source of the tainted water.
Under the new measures, the contaminated water accumulated in the basements of reactor buildings is to be purified and then transferred to storage tanks. At the same time, facilities exclusively used for purifying the tainted water are to be doubled, and the existing storage tanks will be replaced with larger ones, increasing the overall storage capacity.
Meanwhile, the volume of groundwater to be pumped up from the wells near the reactor buildings is to be increased. This is aimed at reducing the flow of underground water into the buildings, thus preventing a vicious cycle of generating more tainted water.
If all goes well, the increase in the volume of contaminated water is expected to nearly stop by 2020. We hope TEPCO will realize this goal steadily.
The measures taken so far have centered on the construction of “ice walls,” to prevent groundwater from entering the reactor buildings by freezing the underground soil around the buildings. Because this step has failed to prove effective even more than half a year after the related facilities were put into operation, TEPCO decided to shift its priority measures.
The new measures will require the approval of the Nuclear Regulation Authority. Both TEPCO and the NRA must cooperate closely so that the necessary work will not be delayed.
Consider ocean release
The reactor buildings have, in effect, turned into storage facilities for contaminated water. The volume of tainted water totals about 68,000 tons. Although the amount of radioactive material contained in the water has declined markedly when compared to the amount immediately after the nuclear accident occurred, it still remains at a high level.
The large amount of contaminated water inside the reactor buildings carries a risk of radiation exposure, posing a serious impediment to the work to decommission the plant. If highly radioactive water starts leaking underground out of the buildings and into the sea, it will create a serious situation.
Even if new measures proceed smoothly, however, tasks remain. The volume of purified water to be stored in the tanks is expected to nearly double by 2020 to about 1.2 million tons. Not only will this entail a huge maintenance cost, but there is also a danger that the water will leak if the tanks are damaged by an earthquake or other factors.
Releasing purified water that has met the existing safety criteria into the sea must be seriously considered. The discharge of purified water into the ocean has been routinely conducted at nuclear power-related facilities both at home and abroad.
It is important for both the government and TEPCO to do their utmost to explain such a plan in detail in order to win the understanding of local residents concerned. Efforts should also be made to take measures to prevent groundless rumors from adversely affecting the fisheries industry and other sectors.
It is also necessary to continuously ascertain the effect of the ice walls. Although nearly 100 percent of the walls have already been frozen, groundwater is reportedly flowing through thin gaps in the walls. Rainwater seeping through the topsoil has also increased the amount of groundwater inside the buildings.
TEPCO is proceeding with work to fill the gaps in the ice walls. If the work proves effective, the goal of reducing to zero the increase in the contaminated water will be realized two years earlier than envisaged. We hope TEPCO will strenuously work to block the flow of groundwater into the buildings. ”