Unit 1 of the Duke Energy (NYSE:DUK) Brunswick nuclear plant in Southport, N.C., went offline unexpectedly Sunday Feb. 7 at 1:26 p.m., due to damage in an electrical panel the company said in a news release.
Duke initially declared an “alert” due to “an explosion/fire in the Balance of Plant 4 kV switchgear bus area,” according to an event report filed with the Nuclear Regulatory Commission (NRC). Prior to the Alert declaration, the operators initiated a manual scram due to an unexpected power decrease from 88% to 40%, according to the report.
The alert was downgraded to an “unusual event” classification at 5:30 p.m. as plant operators realigned plant equipment, Duke said. An unusual event is the lowest of NRC’s four nuclear emergency classifications.
“The licensee has visually verified that there is no ongoing fire and is investigating the initial cause of the event,” according to the NRC report.
Operators safely shut down unit 1. Unit 2 continues to operate at 100% power. All appropriate federal, state and local officials were notified, and Brunswick plant emergency response facilities were staffed, Duke said.
Brunswick Unit 1 was still listed at zero generation by NRC early Feb. 8.
The unusual event was linked to a “loss of all offsite power to Emergency 4 kV buses E1 (E3) and E2 (E4) for greater than or equal to 15 minutes,” according to the NRC report. The emergency declaration was terminated was lifted shortly after 6 p.m. because offsite power was restored.