> there are no working analogs in the US to use as an approved guide
small reactors have been installed on ships and submarines for over 70(!) years now. Reading up on the very first one, USS Nautilus, "the conceptual design of the first nuclear submarine began in March 1950" it took a couple of years? So why is it so unthinkably hard 70 years later, honest question? "Military doesn't care about cost" is not good enough, there are currently about >100 active ones with who knows how many hundreds in the past, so they must have cracked the cost formula at some point, besides by now we have hugely better tech than the 50's, so what gives?