It's true that the Navy spends a lot of money, but it's also true that the Navy can be (and has been) wasteful in terms of spending. What this means is that co

It's true that the Navy spends a lot of money, but it's also true that the Navy can be (and has been) wasteful in terms of spending. What this means is that commercial power can in principle achieve the same safety outcomes with planning and engineering and maybe something south of 'obscene' amounts of money. This is actually what happened when the commercial power industry first started. https://en.wikipedia.org/wiki/Yankee_Rowe_Nuclear_Power_Station https://en.wikipedia.org/wiki/Yankee_Rowe_Nuclear_Power_Stat... There's also the fact that a lot of the expense for the nuclear Navy is having to achieve militarized and maritime variants of gear that can be produced much more simply for civilian applications on land. Fitting anything into a submarine is going to be expensive, including diesel engines, but we don't use that as a reason to say diesel is not practical for civilian transport elsewhere.