” TOKYO (Kyodo) — The operator of the disaster-struck Fukushima Daiichi nuclear plant said Friday its attempt to stop the flow of highly toxic water into underground tunnels by the sea had failed, but it will now try using special cement.
Some 11,000 tons of highly radioactive water has accumulated inside the tunnels — trenches dug to house pipes and cables — which are connected to the No.2 and No.3 reactor turbine buildings, according to Tokyo Electric Power Co.
There are fears that the toxic water — resulting from water injected to cool reactors that experienced meltdowns in the 2011 disaster and from groundwater seeping into building basements — could leak into the ocean and spread pollution.
Removing the water is a necessary step in TEPCO’s unprecedented attempt to create a huge underground ice wall around four reactor buildings at the complex to prevent the toxic water buildup.
Initially, TEPCO sought to freeze water in a section of a tunnel connected to the No.2 turbine building to stop the inflow, before pumping out all the accumulated water. The utility also took some additional measures, but they also failed.
The company on Friday proposed a new strategy of injecting into the tunnels cement filler especially developed for the task, while pumping out as much water as possible.
Under the new method, however, it would be difficult to drain all the water and some radioactive material would remain inside, the utility said, increasing the risk of exposing plant workers to radiation.
A panel of experts under the Nuclear Regulation Authority gave the green light to the new strategy. Some of the experts had claimed TEPCO should stick to the originally planned method and try to remove all the water, while others have argued that giving up on the freezing method may hamper the construction work for the ground ice wall around the reactor buildings.
A TEPCO official explained at the panel meeting that any radioactive water left in the tunnels will be trapped in the cement and the water leakage risk can be reduced drastically. ”