>>1756394At least for planes it's definitely going to be more economic to just run the powerplant on the ground and use power-to-liquid to make artificial kerosene, rather than having to carry around a whole nuclear reactor.
Much safer as well, can't exactly make one light and strong enough to fly while also building it to survive a plane-crash for sure.
With ships, most cargo ships don't actually need that kind of power and, understandably, a derict, badly maintained nuclear cargo ship running on skelleton crew of the cheapest south-asians they could hire, with bare minimum maintenance and questionable procedures, is not something most people would want in their local harbor.
Government vessles at least in theory should have the money to build that thing to be safe, maintain the reactor roughly as required and have staff at hand that has been taught how to operate it (even if they had to lay off the crayons for a minute there).
Renewable methanol seems the way to go for ships.
After all accidents do happen. And accidents involving nuclear reactors tend to get ugly.