The Tennessee Valley Authority (TVA) Watts Bar 1 nuclear facility near Spring City, Tennessee, went offline unexpectedly on March 22, according to a report filed with the Nuclear Regulatory Commission (NRC).
“On March 22, 2016, at 1131 EDT, the Watts Bar Nuclear Plant Unit 1 (WBN1) reactor tripped due to the actuation of the Over Temperature Delta Temperature bistables,” according to the event reported filed with NRC.
“Concurrent with the reactor trip, the Auxiliary Feedwater (AFW) system actuated. All control rods inserted upon the reactor trip. Engineered Safety Function systems functioned as expected,” according to the event report.
The cause of the event is under investigation.
“Once any necessary repairs are complete, operators will return the unit to operation,” a TVA spokesperson said.
Watts Bar 1 is a 1,150-MW pressurized water reactor (PWR) that entered commercial service in 1996, according to GenerationHub data.
A few months ago, TVA received its NRC license to start operating the Watts Bar 2 reactor unit. “Watts Bar Unit 2 is in mode 4 preparing for power ascension testing and was unaffected by the WBN1 event,” according to the NRC event report.