A new water leak, possibly from the effort to cool a crippled reactor, has been detected on the first floor of a reactor building at the Fukushima No. 1 nuclear power plant, Tokyo Electric Power Co. said Jan. 18.
TEPCO said workers discovered by a video feed that water was leaking on the first floor of the wrecked No. 3 reactor building earlier in the day.
The utility added that the water was flowing into the basement of the reactor building and not outside the structure. It is investigating the source of the leak.
TEPCO suggested the possibilities that the water was leaking from a pipe that is sending cooling water to the reactor or from the reactor containment vessel.
If the leak is from water being used to cool the reactor, it would be highly contaminated and a new headache for TEPCO and the government. A series of leaks from storage tanks of water that had been used to cool the damaged reactors and problems with groundwater entering reactor buildings and mixing with radioactive water there has hampered the plant’s decommissioning process.
TEPCO, however, said the latest leak could simply be rainwater draining off. The company said no signs of irregularity have been observed in terms of the operation to cool the reactor.
Radiation levels outside the building and the volume of water sent to cool the reactor and the temperature of the reactor remained the same, it added.
Workers spotted the leak in images sent by a remote-controlled robot when they were operating it to remove debris on the first floor of the building around 2:40 p.m.
The water was coming from near the door of a room housing the main steam isolation valve and flowing into a drain. The flow was about 30 centimeters wide, and the amount of the leak and when it started were unknown, TEPCO said.
Radiation measured about 30 millisieverts per hour near the drain, not substantially different from levels found at other areas of the first floor.