TOKYO (Reuters) - Tons of radioactive water were discovered on Tuesday to have leaked into the ground from Japan's Fukushima nuclear plant, the latest in a series of leaks at the plant damaged in a March earthquake and tsunami, the country's nuclear watchdog said.
More than three months after the disaster, authorities are struggling to bring under control damaged reactors at the power plant, 240 km (150 miles) north of Tokyo.
About 15 metric tons of water with a low level of radiation leaked from a storage tank at the plant on the Pacific coast, the Nuclear and Industrial Safety Agency said.
Plant operator Tokyo Electric Power Co (Tepco) said it was investigating the cause of the leak which was later repaired.
Vast amounts of water contaminated with varying levels of radiation have accumulated in storage tanks at the plant after being used to cool reactors damaged when their original cooling systems were knocked out by the March 11 disaster.
Dealing with that radioactive water has been a major problem for Tepco, which is trying to use a decontamination system that cleans water so it can be recycled to cool the reactors.
But the system has encountered technical glitches and officials have said the water could spill into the Pacific Ocean unless the system was operating properly.
The system was halted an hour and a half after it started on Monday because of a water leakage.
Tepco fixed the problem and restarted the system on Tuesday afternoon, said Junichi Matsumoto, an official at the utility.
(Reporting by Shinichi Saoshiro and Yoko Kubota; Editing by Michael Watson and Robert Birsel)