Unfortunately in the US regulation is technology depended, so the specification might say 'how is your secondary steam loop secured', but of course a molten sal

Unfortunately in the US regulation is technology depended, so the specification might say 'how is your secondary steam loop secured', but of course a molten salt reactor doesn't have steam. You literally can't get approval for anything that is not a PWR. NuScale could kind of slip threw by still being a PWR. NuScale still had some major challenges, one of the reason they had to pay so much is that they wanted 1 control room to control multiple nuclear reactors. That was partly paid for be the government as it will help others as well. If you wanted to do anything other then PWR, you basically have to give them a huge amount of money and a design (couple 100M invested to get there) and then they will take a long time (on your cost) and then potentially develop a regulatory framework and then tell you what your design needs to add. So in practice you are gone be down billions and decades before you get something like a molten salt reactor threw approval. That is why virtually all (at least non DoD) next generation reactors go to Canada to go threw initial deployment. Its hopped that once Canada approves an GenIV reactor other places might be easier to get threw. And thankfully the US is actually looking to Canada and they are considering cross licenses.