Because of a fluctuation in the voltage output from the plant’s generator, the Unit 1 reactor at the Sequoyah Nuclear Power Plant in Soddy-Daisy, TN, tripped for the second time in four days.
Tennessee Valley Authority (TVA) resumed power generation at the Unit 1 reactor at 12:37 a.m. Monday after making changes on plant voltage regulators to limit the type of power fluctuations that caused the reactor to trip and shut down last Friday.
As the reactor got up to about 80 percent of its maximum power output at 10:30 a.m. Monday, the voltage coming off the plant generator began to vary again, forcing another shutdown of the Unit 1 reactor, said TVA spokesman Jim Hopson.
“We felt we had the problems in hand over the weekend, but we are now having to go in and once again troubleshoot the problem to make sure we have corrected whatever problem has caused these fluctuations,” Hopson said. “Obviously, there is concern when you have two of these instances in such short order. We’re going to look very closely at all of our equipment to make sure we have tracked down the source of this problem.”
The voltage fluctuations occurred on the non-nuclear part of Sequoyah and did not present any danger to plant employees or the public, Hopson said. But the reactor automatically shuts down whenever there are problems with the generator, which uses the steam and pressurized water from the reactor to spin a turbine to create electricity.
The Unit 2 reactor at Sequoyah remained unaffected by the two trips and has continued to generate electricity at full power.