I'm the least qualified person to discuss this, so here I go...
These are my immediate thoughts:
(1) If, in the event of a meltdown, I would think surrounded by water would be the best place. In a last-ditch effort, you could always sink it to cool the reactor and stop a meltdown. From what I understand, they currently submerge the rods in water to cool them. When that system fails, that's when you get a meltdown (ala TMI & Chernobyl). If that system fails on a boat, sink the whole thing. Meltdown avoided.
(2) Don't know if it's a problem over there, but it takes away the NIMBY issue.
(3) The more Russia (China, and France) can rely on Nuclear energy, the better. They already have nuke weapons, so we don't have to worry about a new nuclear state. The less dependant on oil they are (1) it's cheaper for everyone (2) it takes money out of the unstable middle-east (3) they would be less likely to fight us on middle-east policy
(4) If it does work, it's a technology that can be tried here, after the Russians have tested and fine-tuned it. If it doesn't work, it's all on them. Either way, we can learn from their experience.