Thorium-based nuclear research was practically shut down during the Cold War precisely because they realized that you can't make nuclear weaponry out of it. It would have been a very different world otherwise.
Thorium-based nuclear research was practically shut down because:
1. General decline of nuclear power plant building after 1970s in U.S. Why financing research for Thorium-based reactor, when even PWRs and BWRs are not build anymore. The shutdown of sodium-based reactor research is another example.
2. Handling of highly radioactive corrosive molten salts in Molten-salt reactor designs is a big issue. Materials resistant to both intensive chemical corrosion and neutron irradiation were open research problem.
3. Online reprocessing of nuclear fuel necessary for some thorium fuel cycle designs (inside the nuclear power plant) could increase the risk of nuclear proliferation. U.S. government, as a general policy, doesn't like when non-weapon states do nuclear reprocessing.
4. Thorium-based reactor could be used to produce weapon usable Uranium-233. But this production was not necessary, as military Plutonium production reactors were already build.
no, weapons production is unrealated anyway - it's cheaper to do it in special facilities. Thorium was just too late to the party when most units were classic PWR's and BWR's without complicated handling
Thorium-based nuclear research was practically shut down during the Cold War precisely because they realized that you can't make nuclear weaponry out of it. It would have been a very different world otherwise.