Frrom the article:
TVA President Bill Johnson said Watts Bar 2, the first U.S. reactor to enter commercial operation in 20 years, would offer clean, cheap and reliable energy to residents of several southern states for at least another generation.
Clean - as long as you don't count the radioactive waste that has to be stored somewhere for the next thousand years.
Stored for the next thousand years, but ideally (if it weren't for NIMBYs) stored in secured and protected underground caverns where the radioactivity is isolated and contained. As opposed to coal, which spreads radioactivity all over the place or fossil fuels which release massive amounts of greenhouse gasses. Isn't it better to make a very small, unused area really dirty compared to making large swathes of used and inhabited lands only kind of dirty? And in those thousand years that we are storing the nuclear waste we may come up with technology that can reuse that waste for some other purpose.