Nuclear is anything but cheap. It's a net negative energy source, meaning the the electricity costs more to produce than it can be sold for. This is why the industry requires massive subsidies to stay alive. (If I recall correctly, the last round of subsidy in the US was over $50 billion.)

Nuclear power also requires massive amounts of carbon, as the uranium fuel must be mined and extensively processed before it is useful. The mining and milling process is horribly polluting and has ruined the land and water in many places on Earth.

Now, having said that, I certainly hope this guy can come up with a way to transmute radioactive elements with lasers. That would be terrific. But I'm doubtful.