OAK HARBOR, Ohio — A minor cooling-system leak found during inspections this week before a post-refueling restart at the Davis-Besse nuclear power plant "may have contained trace amounts of reactor water" but was properly contained and did not pose a public hazard, the Nuclear Regulatory Commission reported.

"NRC regulations require plants to perform extensive inspections throughout the startup process in order to identify problems," agency spokesman Prema Chandrathil said Friday. "The plant identified this leak while conducting one of those inspections. The plant must fix the seal leak before it can start back up again."

A spokesman for Davis-Besse owner FirstEnergy Nuclear Operating Corp. said the plant Friday was "in the process of repairing the small, pinhole defect identified during startup inspections Wednesday.

"We continue to examine the cause of the issue and are using our Corrective Action Process for that investigation," said Jennifer Young.

The leak occurred in a three-quarter-inch weld on a cooling-system pipe. The water, for which flow was estimated at 0.1 gallon a minute, was collected in a containment-sump system designed to capture and process such water, Ms. Young said. No water was released from the plant, she said.

The leak occurred as the company is applying for a renewal of the plant's license.

Relicensing opponents have a petition pending that asks the NRC to consider as a factor in its decision the October discovery of hairline cracks in Davis-Besse's outer concrete shield, or containment, building.

In a report filed in February, the company blamed the hairline cracks on windblown moisture that seeped into the concrete during the blizzard of 1978, then froze, and said there was no evidence the cracks had spread since then.

First Published June 9, 2012, 4:00 a.m.