The Duke Energy (NYSE:DUK) H.B. Robinson Unit 2 nuclear facility in South Carolina went offline temporarily Oct. 8 and declared an “unusual event” due to the “momentary” loss of off-site power, according to an event report filed with the Nuclear Regulatory Commission (NRC).
An unusual event is the least serious of NRC’s multi-phase emergency classifications. It indicates the presences of events that could indicate potential degradation of the level of safety of the plant.
“At 1304 EDT Robinson Unit 2 experienced a momentary grid voltage drop that lowered the 4kV bus voltage and initiated an automatic reactor trip,” according to the report filed with NRC.
The NRC event report made no mention of whether Hurricane Matthew might have factored into the outage.
The situation was corrected and the unusual event designation was terminated after midnight on Oct. 9, according to the report.
As of early Oct. 11, Robinson 2 was listed at 48% power, according to NRC data. Robinson is a single-unit pressurized water reactor (PWR) in Darlington County, South Carolina that can generate roughly 725 MW. Robinson 1 is a retired coal unit at the same location.