https://www.sciencemag.org/news/2020/10/department-energy-pi... an older article that talks about the TerraPower reactor mentioned in the article, they say that it has to run on 20% enriched Uranium, wouldn't that have the potential to create problems with nuclear proliferation?

interesting that only one company seems to be working on a thorium cycle reactor https://flibe-energy.com/ . Why don't they invest more into this direction, instead?