Two days after power production began for the first time at TVA's newest reactor at the Watts Bar Nuclear Plant, the new reactor shut down Sunday.
TVA officials said Tuesday they hope to restart the Unit 2 reactor at Watts Bar later this week and insist power fluctuations are typical of starting a new nuclear unit - especially one that has been under construction or deferred for more than four decades.
The Unit 2 reactor automatically tripped at 12:27 p.m. Sunday when problems developed in the plant's turbine system on the nonnuclear part of the plant. At the time, the reactor was at about 12.5 percent of its maximum power.
"All equipment operated as designed and licensed reactor operators responded according to their training," TVA spokesman Scott Brooks said. "Station personnel are troubleshooting the main turbine control system and after the issue is resolved, power ascension testing will resume and the unit will be returned to service."
The trip is the latest setback for a nuclear plant that has taken 43 years of starts and stops to finish and ended up costing nearly twice as much as what was forecast when the project was resumed in 2007. TVA officials said adding a second reactor at the Spring City, Tenn., facility is still cost effective because it cost only about half the expense of other new nuclear plants and can operate along with the Unit 1 reactor for a fraction of the operating costs for most fossil fuel power plants.
The unit 2 reactor began power production last Friday - two weeks after the unit first achieved initial criticality with a self-sustaining nuclear reaction in the reactor core. TVA will undergo a series of power ascension tests in which the power in the unit will both be raised and lowered to test key equipment in the new plant. TVA expects the new reactor to be at full power and declared a commercial unit sometime this summer.
"Identifying issues as equipment is rigorously tested is expected with a complex project such as this," Brooks said. "It is a challenging task to bring a unit into operation the first time, and we will continue to take the time to properly address each issue identified, ensuring that TVA's newest generation asset is safe to operate in every respect."
Watts Bar Unit 2 is the first American nuclear reactor to be added to the electric grid in 20 years. When in full production, the two units at Watts Bar are capable of supplying the electricity needs of about 1.3 million people.
Contact Dave Flessner at dflessner@timesfreepress.com or at 423-757-6340.