You can't make a patent secret. That's the point of patents, we're not a system of trade secrets. Knowledge gets shared when the patent is approved even though exclusive rights are retained by the inventor for 20 years. I'm sure the majority of thorium reactor technology patents are expired since research ended so long ago. Now if the researchers never patented their research and kept it secret that's another matter.

There are many corners to pass for a technology to become mainstream. Fuel Cells have already passed several of these. They've gone from an idea on a blackboard, to a gadget in a lab, and now multiple large companies have put out prototype devices. The Honda fcx clarity car being and portable batteries being just two. Fuel cell buses are already prowling the streets of several cities. Probably the biggest advances yet to come are cost, large scale production, and wide scale distribution of fuel for the fuel cells. The fact is fuel cells are here now and already working hard, they just need more improvements to be mainstream.