Nuclear is very expensive to build. It takes a long time to build. Also, it takes quite a bit of time to power up and power down a nuclear power plant. Nuclear plants use a lot of water. Water that could be used to cool the AI hardware. As a result nuclear power isn't cheap.

Then there is still the safety issues and environmental concerns regarding the waste. Some people say they are safe now and you can just bury the waste deep underground. Putting it deep underground seems a bit like just pumping the carbon into the air: someone else's problem further down the line in time.

Do you want to live next to a Nuclear Power Plant?