content: It is unfortunate that the US government decided that pressurized water reactors using uranium were the way nuclear power should be done as opposed to liquid fluoride thorium reactors. That decision was likely made because spent fuel from a reactor running on lightly enriched uranium can be reprocessed to make plutonium-239 for nuclear weapons. Compared to pressurized water reactors liquid fluoride thorium reactors are safer in the event of loss of cooling/power , produce less high level radioactive waste, and uses up thorium which is a waste product of the rare earth mining industry without needing the isotopic enrichment of uranium. The Oak Ridge National Laboratory built the Molten Salt Reactor Experiment back in the 60's to prove out some of the concepts but the second phase where they would use thorium got canceled. There is a good period documentary about the MSRE here (20 minutes).