Tokyo Electric Power Co. admitted Monday that the so-called groundwater bypass operation at its crippled Fukushima No. 1 nuclear power plant is not working.
In May, the utility began the operation to pump untainted groundwater into the sea to prevent it from flowing into and accumulating in reactor buildings.
The operation is intended to reduce the tons of radiation-tainted water being generated by the plant each day. The melted reactor fuel at the plant, which was heavily damaged by three core meltdowns after the March 2011 earthquake and tsunami, must be perpetually cooled by water that then leaks into the basements and taints incoming groundwater from the hills behind the plant.
Tepco official Teruaki Kobayashi told a news conference Monday that the utility has yet to see tangible results from the operation in the reactor buildings.
According to Tepco, 400 tons of groundwater flow on average into reactor buildings and other areas at the plant per day, causing the buildup of contaminated water. The company has said the operation could lower that amount by up to 100 tons per day.
Two months after the start of the operation, however, there is still no sign that the buildup of contaminated water has been halted. Even so, Kobayashi noted that water levels had dropped by up to 10 centimeters at the point halfway between the reactor buildings and the wells used to pump out groundwater.
Rainfall at the plant site has been hampering the operation, Tepco said, adding that it plans to solidify the soil with asphalt near the hills where the groundwater flows from, according to NHK.
For the water inflow to decline by 100 tons per day, levels at the halfway point need to fall by several dozen centimeters, to 1 meter.
Kobayashi declined to specify when groundwater levels could begin to fall.
A total of 15,828 tons of groundwater was released into the sea between May 21 and July 20.