The Notification of Unusual Event sent to federal, state and local officials on Sunday is the lowest level of four Nuclear Regulatory Commission alert classifications.
TVA said the malfunction occurred in a non-nuclear section of the plant's electrical distribution switchyard. There were no injuries and the notification sent at 8:34 a.m. was followed by a termination of notice at 10:19 a.m.
About 10 gallons of cooling oil leaked from a power circuit breaker and was cleaned up.
Both reactors at the plant continue to operate at full power.