The Tennessee Valley Authority successfully completed a key test at its Watts Bar 2 nuclear reactor, bringing it closer to commercial operation, a spokesman said.
TVA’s Watts Bar 2 is the nation’s first reactor set to come online in nearly 20 years. It is expected to do so by the end of the summer, TVA spokesman Jim Hopson said.
Yesterday’s test involved running the reactor at 30 percent power and tripping the turbine. The reactor’s emergency diesel generators are supposed to start up once that turbine trips offline.
Both happened as planned in the afternoon, Hopson said.
"We still need to look at the test data, but we believe it was a successful test," he said in an interview with EnergyWire.
TVA is nearing the last phase of testing known as "power ascension." In this phase, workers are testing how the reactor operates while producing electricity at incremental levels, starting at 25 percent and going up to 100 percent.
It also means the reactor is online and producing power on its own, and the turbine is officially tied to the transmission system, Hopson said. The reactor is at Watts Bar Generating Station in southeast Tennessee.
"Having that generator synced to the grid, that’s when you’re producing power people can use," he said. "The entire system is working how it’s supposed to work."
Another key part of power ascension testing is a "load rejection" test at 10 percent. This makes sure Watts Bar can operate under a sudden loss of load on the system, which is what could happen if a tornado strikes the area and hits part of TVA’s transmission system.
The 1,150-megawatt unit is important to TVA for many reasons. It has been under construction since 1980. After years of stalled construction, TVA revived the project in 2007.
Nuclear makes up roughly one-third of TVA’s electricity mix. Once Watts Bar 2 is commercially operating, that figure moves up to 38 percent.
Different markets, different challenges
Watts Bar 2 is coming online at a time when more than a dozen U.S. reactors are slated to be shut down for economic reasons. Most of those merchant plants are in the Midwest, however, where a glut of shale gas and in some cases cheap wind prices are making them uneconomical to run.
Meanwhile, the nuclear executive of neighboring Southern Co. is challenging the nuclear industry to produce 40 percent of U.S. electricity by 2040 (Greenwire, July 13). Watts Bar 2 will have to be a key part of that as just two other electric companies are building reactors.
TVA also is the first company in the United States officially to explore the option of building a small modular reactor.
Watts Bar has been in the news for other reasons. The unit had tripped offline during June tests. The incident shows why reactors must be tested at various power levels, officials said.
"We have a sense of urgency to successfully complete this testing and to get this unit into service, but we’re going to take whatever time we need to do to get it right," Hopson said.
TVA executives also are trying to improve communication and culture at Watts Bar 2. Both had degraded as an unintended consequence after management wanted to improve operational performance (EnergyWire, May 25).
TVA officials met with the Nuclear Regulatory Commission in May to walk through the steps they have taken to improve the working environment. There have been no serious incidents or accidents at the reactor.
