Missouri’s Callaway nuclear plant declared an alert Sunday after a leaking air conditioner disrupted access to part of an auxiliary building.
Ameren Missouri declared the alert at 10:56 a.m. and exited it at 5:37 p.m., according to a company release. The reactor remained online throughout, and the event did not compromise public safety.
According to a Nuclear Regulatory Commission event report, toxic freon gas that leaked from one of the control room air conditioning units jeopardized "operation of systems required to maintain safe operations or safely shutdown the reactor."
Repairs were soon underway, Ameren reported, and plant personnel were not at risk. An alert is the second lowest category on the NRC’s four-level emergency scale.
Ameren operates a single 1,236 megawatt Westinghouse pressurized water reactor at the site near Fulton, Mo.