Workers have successfully stopped a leak of Freon vapor in the unit 1 reactor building at PPL’s Susquehanna nuclear power plant in Pennsylvania, ending an alert that had been in effect since 10 August.

Freon is used as a refrigerant in the air-conditioning system for the reactor building and provides cooling to pump motors.

The alert – the second lowest of four emergency classifications used by the Nuclear Regulatory Commission – was declared at 9:22am after a toxic gas (believed to be Freon) was identified in the unit 1 reactor building. The gas had leaked from one of the chillers.

As a precaution, PPL, which owns and operates the two-reactor plant, evacuated that building.

On 11 August, PPL confirmed that the Freon had been safely removed from a chiller in the unit 1 reactor building and had been placed in storage tanks on site.

“While public safety was not at risk during this situation, entering the emergency management plan ¬– which involves cooperation from many municipal, county and state agencies – ensured we had the resources available if needed to help protect employees and support the safe operation of the plant,” said Miriam Mylin, spokeswoman for the Susquehanna plant.

PPL ended the alert declaration at 11:35p.m. EDT on 10 August.

Both generating units at the plant are operating at full power.