Eh, it’s honestly safer than you’d think. The size of the reactor plays a huge role in safety.

A reactor sized for a container ship would be literally incapable of melting down, because there just isn’t enough fuel to get to those temperatures. You could then limit the ship’s speed, and over build the reactor a bit, so that the reactor is never truly stressed during normal operation.

Then for refueling, you just remove the entire reactor and replace it with a new, fully fueled one every 10 years or so.

That’s where you want your controls.

Other than that, yeah it would be safer than oil. A crash just means your reactor casing gets wet.

The main worry is someone cutting into the reactor to take out the spicy rocks… and there are easier ways to get spicy rocks.