The Tennessee Valley Authority (TVA) Sequoyah 1 nuclear unit in Tennessee went offline March 1 following a malfunction, according to a report filed with the Nuclear Regulatory Commission (NRC).
The automatic reactor trip resulted in the unit going from 100% power to zero power generation. There was no operational impact to Sequoyah Unit 2. Unit 2 continues to operate at 100%.
“The immediate cause of the trip was a Power Range Nuclear Instrumentation negative rate signal, caused by a malfunction in the rod control system. There was no associated work in progress related to this and all systems were normally aligned,” according to the report filed with NRC.
“Operators at TVA’s Sequoyah nuclear power plant are determining the cause of an unplanned change in power rate that initiated an automatic shutdown of the Unit 1 reactor at 6:21 a.m. EDT on Wednesday, March 11,” a TVA spokesperson told GenerationHub. “All systems performed as designed and there were no safety consequences to the public or plant personnel,” the TVA representative said.
“Post-trip investigation is in progress and planned restart timeline has not yet been determined,” according to the report filed with NRC.
Sequoyah Units 1 and 2 are pressurized water reactor (PWR) units in t Soddy Daisy, Tenn. Each unit has a nameplate capacity of roughly 1,200 MW.