Faulty pipe in Japan accident 'not inspected'

The faulty cooling pipe at the centre of Japan’s deadliest nuclear power plant accident had not been inspected since 1996, despite a warning last year that it was a safety threat, the plant operator said.

The dangerously corroded pipe – which carried boiling water and superheated steam – burst at the Mihama reactor yesterday, burning to death at least four workers and injuring seven others, two of them seriously. No radiation was released, officials said.

The announcement came as dozens of police agents and nuclear energy officials arrived at the plant in Mihama, about 200 miles west of Tokyo, to investigate operator Kansai Electric Power on suspicion of negligence resulting in death.

The accident and suspected lapses deepened concerns about the safety of Japan’s 52 nuclear plants, which supply about a third of the country’s electricity. Two workers died in a radioactive leak at a plant northeast of Tokyo in 1999.

It was unclear how the accident would affect the operation of Japan’s other nuclear plants. The country’s nuclear agency was considering a call for all plants to inspect their cooling pipes, a spokesman said.

Kansai Electric deputy plant manager Akira Kokado said private contractors conducting inspections for the company notified management in April 2003 that the cooling pipe at the Mihama plant was overdue for a thorough safety check.

Sections of the pipe were last checked in 1996 and deemed safe at that time, said Koji Ebisuzaki, Kansai Electric’s chief manager for quality control.

The national government in Tokyo – which plans to build another 11 nuclear power plants by 2010 – called for a public investigation of the accident.