I had another “Thorium? what’s That?” discussion today so I thought I would link to another primer on the issue.
There seem to be very few downsides to thorium. The resistance seems to come from negative assumptions made by people based on problems with the uranium/plutonium cycle.
It is also important to note that governments, including ours, have been resistant to thorium precisely because it is cleaner and safer. It has little or no (apparently zero) military use so a thorium plant can’t be a stalking horse in which weapons grade fuels are produced under the cover of civilian power production.
In fact, if Iran wants peaceful nuclear power as they say they do, we should build them a thorium plant.