If the reactor on a nuclear sub were breached, what would happen?

Dear Cecil: During the Falkland Islands naval battles years ago I got to thinking about what might happen if one of Britain’s nuclear subs was destroyed and its nuclear reactor breached. Would calamitous China Syndrome (or Poseidon Syndrome) effects necessarily result? Would there be massive fish die-offs? An end to life as we know it? Robert B., Dallas

Cecil replies:

Funny you should mention it, because I was reading up on this subject in one of my environmental journals, which I rely on to keep me abreast of the latest threats to civilization. The real danger nowadays, it seems, isn’t so much from ship-borne nuclear pollution of the oceans (although this situation could change–more below), but rather from the space-borne variety–specifically, from falling satellites with nuclear reactors aboard. During the days of the Soviet Union, atom-powered Russian reconnaissance satellites tumbled earthward at least twice. One disintegrated over the South Atlantic (apparently harmlessly, although you never know about these things), while the reactor from the other crashed into a frozen lake in northern Canada. Authorities successfully retrieved the 143-pound chunk of lethal debris in the latter case, but if I were you I would eye any Canadian lake trout I might be presented with in the next 6,000 years with deep suspicion. The nuclear power pack from a U.S. weather satellite fell into the Santa Barbara Channel off California in 1968, whence authorities managed to recover it, but another power pack was lost for good in the Pacific north of New Zealand in 1970. Fortunately, its heavy shielding supposedly won’t disintegrate for some 860 years.

But back to ships. You may recall there’s been some talk of the U.S. Navy disposing of its obsolete nuclear submarines by the straightforward method of scuttling them in mid-ocean somewhere. The nuclear fuel would be removed first, but opponents say enough radioactive junk would remain on board to pose a significant pollution hazard. As for what will happen on that inevitable day when a nuclear reactor actually breaks open in the ocean–well, I dunno, and neither does anybody else. Certainly the China Syndrome (i.e., a massive meltdown) will not occur, due to the cooling effect of the seawater. The pollution, however, could be disastrous. No doubt we’ll find out soon enough.

Cecil Adams

Send questions to Cecil via cecil@straightdope.com.