OMAHA, Neb. (AP) — Workers are repairing a hydrogen leak at Cooper Nuclear power plant in southeast Nebraska after the problem was discovered in one of the turbines during maintenance.

Nebraska Public Power District spokesman Mark Becker says the small hydrogen leak isn’t in the power plant’s nuclear systems, and it doesn’t represent a safety threat.

The plant near Brownville, Nebraska, continued operating after the leak was found Tuesday morning.

Becker said the utility is working to repair the leak by the end of Tuesday. The hydrogen is used to help cool the turbine.

The utility notified regulators about the problem, and issued what the Nuclear Regulatory Commission calls a notice of unusual event.

NRC spokesman Joey Leford said the agency’s inspectors are monitoring the repairs.