It's an interesting question, that one, isn't it? I don't think "nuke" is the operative word because they would want a tiny nuke so "conventional" explosives might do. From what I hear Prof. Bea and some other sources saying I infer that the real danger of that approach is that it can make things much, much worse. (Namely, while it might collapse the pipe, it might also create a large total volume capacity of escape paths for the oil, spread over a larger area. There is already a new leak from the sea-bed 400ft away.).