Watts Bar Nuclear Plant

Watts Bar Nuclear Plant is located just south of Watts Bar Reservoir on the Tennessee River near Spring City in east Tennessee. It is TVA’s third nuclear power plant. Construction began in 1973, and Unit 1 began full commercial operation in 1996. In 1988 TVA suspended construction of Unit 2 because of a reduction in the predicted growth of power demand. In August 2007, the TVA board of directors approved completion of Unit 2 and construction has resumed.

Nuclear power production

The operating unit at Watts Bar is a pressurized water nuclear reactor. It makes electricity by splitting uranium atoms to produce steam. The steam is piped to the main turbine, which spins a generator to produce electricity.

Once the steam leaves the turbine it is cooled in an area called a condenser and changes back to water. The water is pumped back to the reactor to begin the process again.

Uranium fuel for the reactor is refined from ore and formed into ceramic pellets about the size of the end of your little finger. The pellets are stacked one on top of the other in long tubes called fuel rods. The fuel rods are bundled together to form a fuel assembly.

When the fuel assemblies are placed in the reactor, heat from the splitting uranium atoms raises the temperature of the water surrounding the assemblies to about 580 degrees Fahrenheit. Because this water is under high pressure, it doesn’t boil.

The pressurized water goes to tubes in a steam generator. A secondary supply of water passes around the outside of the tubes. This second source of water boils and turns to steam, which is piped to the turbine to drive the generator.

Control rods and borated water are used to control the splitting, or fission, of the uranium atoms. The borated water speeds up or slows down the fission process. The control rods shut down the reactor when they are inserted between the fuel rods.