Rockets blow up because that's what rockets do. You can absolutely build reasonably safe test reactors to verify ideas. That is what they did constantly in the

Rockets blow up because that's what rockets do. You can absolutely build reasonably safe test reactors to verify ideas. That is what they did constantly in the 60s, with multiple new reactors every year. The whole Molten Salt reactor experiment was something like 70 million $ for an amazing project. And dispute that somehow the world didn't blow up and there are no mutant ninja turtles anywhere. What helped SpaceX out was the COTS and CRS program, and something like that could absolutely be world changing in nuclear, but nobody at the DoE has that kind of vision sadly. In fact the mastermind behind COTS has been advocating for something like that for many years now.