Japan's Kyushu Electric halts output from recently restarted reactor after steam leak

TOKYO (REUTERS) - Japanese utility Kyushu Electric Power stopped producing electricity at a recently reactivated nuclear reactor at its Genkai station in the southwest of the country on Saturday (March 31) after detecting a steam leak late on Friday.

A spokesman said on Monday that no radiation had been detected as a result of the incident. She said the utility did not know whether the issue would delay the reactor's return to full commercial operation after a seven-year shutdown.

The setback highlights the technical difficulties of restarting a reactor closed for a lengthy period. The company does not know whether it will delay the restart of another unit at the plant set for next month (May), the spokesman said.

Many of Japan's reactors are still going through a relicensing process following the 2011 Fukushima disaster, the world's worst since Chernobyl in 1986, which highlighted regulatory and operational failings at nuclear utilities.

Kyushu Electric had restarted the No. 3 reactor at the Genkai plant on March 23, and began generating and supplying electricity on March 25.

But the spokesman said during an inspection over the weekend that the company had detected a 10mm hole in a pipe in a system to take out and discharge excess oxygen and carbon dioxide gas.

"The cause of the steam leak is still unknown. We will continue our inspection to find out the cause without taking it (the reactor) offline," she said.