An explosion in the Harris nuclear plant's switchgear prompted an alert at the North Carolina reactor Thursday.
An electrical bus that provides power to safe-shutdown equipment exploded at about 2:30 a.m., according to a Nuclear Regulatory Commission event report. Operators brought the unit down to 92 percent power to compensate for the loss of moisture separator reheaters, according to the NRC, and an emergency diesel generator was found to be inoperable because of air compressors without power. The explosion did not result in a fire. No offsite assistance was required, and the alert ended at 5:33 a.m.
The single-unit plant located near Raleigh, N.C., uses a 928 megawatt Westinghouse pressurized water reactor. The plant was first licensed in 1986, according to the NRC, and is operated by Duke Energy. While the reactor itself was not at risk, the agency requires an emergency declaration in the event of "an explosion of sufficient force to damage permanent structures or equipment within the protected area."