Even before the first nuclear weapon, someone decided to make a big, critical tank of aqueous uranium salts. Turns out we're still using the basic idea to make technetium and other medical isotopes. They're super safe because, if it all goes wrong, you just take the plug out of the bottom and the whole fuel "assembly" flattens out politely into a big cold sheet. Plus, you can do 100% online reprocessing, because you can just circulate fuel out, and xenon and other byproducts just kinda bubble out. The catch is that they make hydrogen and oxygen by splitting water with hard radiation, but that's also an upside. Anyway, I had never heard of these even though I'm a huge nuclear salt water rocket fan -- pretty neat!
they made piss 2 in 1944 we don't know SHIT