Inside Watts Bar Nuclear Plant — One of The Longest Building Projects in US History

Construction has taken so long, the newest U.S. nuclear plant will run on 70s-era technology.

It’s taken so long to complete, the newest nuclear plant in the U.S. will run on 1970s-era technology. But finally, after nearly four decades, the second reactor at the Watt Bar Nuclear Generating Station in Tennessee is 90 percent finished.   

Construction of the plant got underway in 1973, six years after the Tennessee Valley Authority announced plans for 17 new nuclear reactors in Tennessee, Alabama and Mississippi. But by the 1980s, a down economy and high construction costs caused the TVA to scrap plans for nearly half of those plants.

Work on Watts Bar nevertheless carried on — but regulatory issues slowed progress and the first reactor wasn’t operational until 1996.

The second reactor, meanwhile, was mired in its own delays, including construction costs that ballooned to $4.3 billion over the last decade (2007 estimates projected the costs would total about $2.5 billion). 

But better late than never, says TVA. Although electricity demand in Tennessee has remained flat, TVA says the new reactor — which will provide enough electricity to power 650,000 homes — will help replace energy from coal plants as they go off line. Adjusting the energy mix to give nuclear a bigger piece of the pie will also help reduce the state’s greenhouse gas emissions. Currently, electricity generated by TVA is 43 percent coal, 36 percent nuclear, 12 percent hydroelectric, 9 percent natural gas (with a small amount of oil) and less than 1 percent non-hydro renewables.

According to an Associated Press report, using the older technology has posed unique issues during the reactor's construction. "TVA pulled out many old pieces of equipment for replacement or refurbishment. The U-shaped control room for the newest reactor was designed to look just like the first, even though some of the underlying technology has changed," AP reported.

According to a Forbes report, the plant has been built to withstand earthquakes, any huge dam failures, a tornado hurling a 4,000lb object at it — and even an airplane crashing into it. 

The second Watts Bar reactor is slated to become operational late next year.