TOHOKU Electric Power Co, Japan's fourth-largest electricity generator, has shut a nuclear reactor after detecting a waste-disposal problem.
There was no radioactive leakage at the Onagawa Plant in Miyagi prefecture, according to a statement released on Saturday on the company's Website.
Tohoku Electric halted the No. 3 reactor at the plant in northern Japan on Saturday after a rise in hydrogen levels in pipes disposing of gaseous waste was detected following a regular inspection, Bloomberg News reported.
The company is investigating the cause of the problem, according to the statement.
A spokesman for the firm, which is based in Sendai City, wasn't immediately available for comment yesterday.
Tohoku Electric shut a 524-megawatt reactor at the Onagawa power
station in May after discovering a mechanical fault in a back-up pump that supplies water to cool the unit.
The reactor was reopened in July after extensive repairs.
Tokyo Electric Power Co, Asia's biggest generator, said on October 31 it expected its first loss in 28 years in the wake of fixing a damaged reactor and switching to costlier oil and gas-fired generation.
The Tokyo-based company will spend 164 billion yen (US$1.48 billion) to repair the Kashiwazaki Kariwa station, which was damaged by a magnitude 6.8 earthquake which hit the area on July 16.
The quake caused 2,947 "improper incidents" at the plant, according to surveys conducted by Tokyo Electric.