Tokyo Electric Power Co (TEPCO), the operator of the crippled Fukushima Daiichi nuclear plant, has gotten approval from the government nuclear watchdog to build an ice wall to reduce the contaminated groundwater accumulating at the plant. This is part of their three-pronged approach to reduce the groundwater’s inflow, one of the biggest problems that the plant is facing in their decontamination efforts.
The Nuclear Regulation Authority (NRA) had several concerns regarding the ice wall plan, which was proposed by TEPCO and the Agency for Natural Resources and Energy. The watchdog was looking for proof that the ice wall would be effective in stopping the inflow of the groundwater and at the same time, that it would not hinder in the cooling operations at the Fukushima Nos 1-4 reactors by causing the buildings to tilt because of the possibility that the wall may lower the ground level. TEPCO estimates that the ground level fall would only be at 1.4 to 1.6 meters and assured the committee that “the reactor buildings will hardly move.”
After reviewing the evidence from TEPCO, the NRA decided to give the approval for the ice wall, which the Ministry of Economy, Trade and Industry want to start building by next month. The project will see 26.4 meter-long freezing tubes that will be inserted into the ground with intervals of 1 meter. The tubes will have minus 30 degree Celsius cooling liquid circulating through it which will freeze the groundwater located nearby. It is expected to create a 2 meters thick, 30 meters deep and 1.5 kilometers long ice wall that will box in the four reactor buildings, thereby blocking the flow of groundwater that will be contaminated by the radiation at the reactors. The wall is estimated to be finished by fiscal 2015.
[ via Mainichi ]