system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why are we not using nuclear propulsion in commercial ships?

Probably not passenger cruise ships, but I would imagine commercial cargo ships would profit tremendously from nuclear power. So why is it that nobody has even attempted (to the best of my knowledge) to use nuclear propulsion for commercial goals. Is it the fixed cost of installing such an engine? Or is it the government's fear that nuclear material may end up in the wrong hands?
gpt
It's way, way, *WAY*, too expensive.

The power plant alone would probably be more expensive than the entire lifetime cost of an average bulk carrier. Not to mention the insane mess of regulation that is involved with running a nuclear reactor.

Basically, big ships run on bunker fuel, and bunker fuel is ludicrously cheap.