Kyushu Electric Power Co. said Saturday that 1.8 tons of radioactive water leaked in the purification system of an idled reactor at the Genkai power plant in Saga Prefecture, and drew flak for failing to promptly disclose the incident to local authorities.
The utility detected the leak Friday morning but only told local governments it was having pump troubles with its No. 3 reactor, which is undergoing a regular check.
The lack of disclosure upset Genkai Mayor Hideo Kishimoto.
"It should have been reported properly (to the town of Genkai and Saga Prefecture). I have been repeatedly telling Kyushu Electric to change its corporate culture," he said.
The water leaked from an area involving the pumps, but all radioactive materials were contained within the reactor building, the utility said.
The water has been completely recovered but the intensity of the radioactive matter it contained is unknown, Kyushu Electric added.
On Friday, the company said the alarm system that sounds in the event of a leak was triggered after the temperature at the base of one of the pumps passed 80 degrees, but the leak wasn't identified as the water was contained within the purification system.
The Nuclear and Industrial Safety Agency said the leak within the purification system did not pose an immediate safety threat and urged Kyushu Electric to investigate the cause.
The plant's reactor 4 resumed operation in early November, becoming the first to be restarted since the nuclear crisis erupted at the Fukushima No. 1 power plant.
The reactor had been taken offline after developing a technical problem.
