All of a sudden, the nuclear industry has gone from being radioactive (as in, don’t touch) to red-hot, as artificial intelligence (AI)-related firms look to “always on” nuclear power to meet their electricity needs. One example of that was the recent deal between Microsoft (MSFT)and Constellation Energy (CEG)to restart the undamaged reactor at Three Mile Island. It was a great deal for Constellation, which I discussed here. And now, Founders Fund – the venture capital firm co-founded by billionaire investor Peter Thiel – is backing a nuclear start-up aiming to produce the fuel used to power th…