There are multiple nuclear reactors sunk into the ocean already. Japan could shove the entire Fukushima complex into the sea and it wouldn't come close to doing what coal has done to poison the oceans.

Note that even if you think radiation is particularly scary and vastly worse than chemical poisons, coal power plants emit many tons of uranium in addition to all the other nasty pollution.

What is your basis for that last statement? Coal: about a million deaths per year. Nuclear: about half a million ever, including weapons. Given that, how can you possibly say that damage from nuclear is orders of magnitude bigger?