How would a nuclear explosion react in space?

And also, how do you think a nuclear explosion would react near the event horizon of a black hole?
Update: Would nuclear fusion and fission react the same way in space?
Update 2: warchild when you say a nuclear explosion would react the same way in space as on land, what do you mean? It wouldn't make a mushroom cloud, and the radiation would react in a weird way.
13 answers 13