The Tennessee Valley Authority (TVA) Sequoyah 2 nuclear reactor was unexpectedly forced to go offline during the evening on March 2, according to a report filed with the Nuclear Regulatory Commission (NRC).
The unit “automatically tripped” at about 6:45 p.m. EST, according to the NRC event notification report.
“The immediate cause of the trip was a main generator C phase differential relay actuation. There was no associated work in progress related to this and all systems were normally aligned. It is currently not understood why the relay actuated,” according to the report.
Sequoyah Unit 1 continues to operate at 100% generation. “There was no impact on public health and safety. Post-trip investigation is in progress and planned restart timeline has not yet been determined,” according to the report.
Sequoyah Units 1 and 2 are both roughly 1,100-MW pressurized water reactors (PWRs) located in Soddy Daisy, Tenn.