FUKUSHIMA - Tokyo Electric Power Co. has confirmed that radioactive water has been leaking from two locations inside the No. 1 reactor building of the Fukushima No. 1 nuclear power plant, the utility said.
The contaminated water leak was confirmed Wednesday near a doughnut-shaped pressure suppression pool that is connected to the bottom of the reactor's containment vessel.
It was the first time TEPCO confirmed a water leak from a reactor containment vessel among the Nos. 1, 2 and 3 reactors, where nuclear fuel has melted.
The removal of melted fuel from the three reactors is considered the most difficult aspect of decommissioning the Fukushima No. 1 power plant, which could take 40 years.
Halting the leakage of radioactive water is said to be the first step to be completed for decommissioning. Identifying where the leaks are represents significant progress toward the removal of the melted fuel, observers said.
Radioactive water is accumulated in the basement of the No. 1 reactor building. When TEPCO sent a boat about 90 centimeters long carrying a camera into the basement Wednesday, it recorded footage on the southeast side of the basement of water running down an exterior of the pressure suppression pool near a vent pipe that connects the reactor containment vessel and the pressure suppression pool.
Although TEPCO could not confirm any cracks or holes with the camera, a utility official said there has likely been damage to the upper part of the pressure suppression pool or to a pipe that passes above the pool.
In the northwest side of the basement, TEPCO also confirmed that water was leaking from a damaged drain pipe for condensation. The drain pipe is attached to the bottom of the containment vessel.
TEPCO checked about half the pressure suppression pool Wednesday, and was expected to investigate the remaining part Thursday. Radiation levels inside the reactor building were so high-at 0.9 to 1.8 sieverts per hour-that TEPCO officials were not able to enter the site.
Since the outbreak of the nuclear crisis, TEPCO has continued pouring water into the reactors to cool the fuel. However, the water is believed to be flowing underground.
The origin of the leaking water was previously unknown, hindering recovery from the disaster, the observers said.