The navywouldnotneed touse a nuclearweapon, Clinton said, explaining that the navy couldsimply "blow upthe wellandcover the leak with piles and piles and piles of rockanddebris."
Also, bear in mind that when estimating likely collateral damage, operators will take account of blast, fragmentation, and debris prior to deploying any weapon.
Unless it somehow managed to burrow a very long way down before exploding, such a weapon detonated beneath the earth's surface would throw up huge amounts of radioactive debris, a danger to all.