Refueling of the newest reactor at the Sequoyah Nuclear Power Plant near Soddy-Daisy, TN, wrapped up and the plant is back up and running.
Plant operators increased power at the Unit 2 reactor during the week and were waiting for it to reach full power. At full power, the plant generates enough electricity to serve 650,000 homes, said officials at the Tennessee Valley Authority.
During the outage over the past couple of weeks, TVA replaced 80 of the unit’s 193 fuel assemblies and conducted detailed inspections of the reactor vessel to confirm all components meet design requirements to try to limit unplanned outages like the four this year on Unit 1 that resulted in extra regulatory oversight of the plant.
During the Unit 2 outage, TVA also rebuilt a high pressure turbine and replaced a reactor coolant pump motor and a main steam safety valve.
“The entire Sequoyah team, supported by more than 700 supplemental contract workers, successfully completed approximately 10,000 activities while working more than 138,000 man-hours,” said Chris Schwarz, Sequoyah’s new site vice president.
The refueling is the first since the U.S. Nuclear Regulatory Commission (NRC) elevated its oversight of Sequoyah last month due to the excessive number of reactor trips during 2015.
The NRC said there was one trip last winter and three this summer at Unit 1, the older of two reactors at Sequoyah.
NRC guidelines provide when a reactor has more than three unplanned shutdowns in 7,000 operating hours, there is a stepped-up review of the plant by regulators. NRC charges the costs of those inspections to TVA.
Sequoyah’s twin reactors are among a half dozen TVA nuclear reactors operating across the Valley, supplying nearly one-third of all electricity used by more than 9 million people in TVA’s seven-state region.
Last week, TVA also completed the loading of fuel into its newest nuclear plant — the Unit 2 reactor at the Watts Bar Nuclear Plant near Spring City. TVA spokesman Jim Hopson said plant workers are testing pumps, valves and pressurized systems at the unit before beginning the nuclear fission process in the reactor to create the heat and steam to generate electricity.
Following further tests and power ascensions, TVA expects to put the Watts Bar unit into commercial, full-time operation by next spring, Hopson said.