<p>No matter whether a nuclear or conventional weapon hit a nuclear reactor, there would be no additional threat. If it was a conventional weapon, you’d have a “dirty bomb” and if it were nuclear you’d have a bit more fallout.</p>
<p>However, first off it’ll probably be in the middle of the ocean. Secondly, if it’s docked and we get hit the small amount of fallout willl probably not be a chief concern. This assumes a breach of the reactor vessel, not just a missile hitting the ship. And, since a lot of the systems would sink into the water, that would provide a very good barrier.</p>