Update: Gunshots fired involving a TVA nuclear security officer outside the Watts Bar nuclear plant

photo Watts Bar
Arkansas-St. John's Live Blog

A TVA security officer patrolling on utility property near the Tennessee River at Watts Bar Nuclear plant exchanged gunfire with an unknown person early Sunday morning, according to regulators with the U.S. Nuclear Regulatory Commission.

TVA said there was no threat to public safety, but the agency declared an "unusual event" to the NRC, spokesman Roger Hannah said. An unusual event is the lowest of the NRC's four emergency classifications.

Hannah said NRC staffed its incident response center in the commission's Atlanta office and monitored the events along with the NRC resident inspector who responded to the site at about 2 a.m. when the event occurred.

TVA returned to normal operating mode shortly after noon Sunday, nearly 12 hours after the shooting incident. NRC soon followed suit, but both TVA and NRC are continuing to investigate the incident, Hannah said.

TVA spokesman Jim Hopson said TVA - like all federal facilities presently - remains under high security alert in the aftermath of the Boston bombings last week.

Read more about the incident in Monday's Chattanooga Times Free Press.