I've had dreams where the Horizon was full of nuclear explosions. Recently I had a dream in which a Nuclear Warhead went off fairly close by. The Light was one thing, but I was worried about the shock wave, but luckily I was far enough away so the physical damage that rolled by was not fatal, but then again, nothing is fatal in a Dream.

What you need to do is 'live' through one of these Explosions. You need to learn that nothing can kill a Dream Self. Your waking up is like a symbolic death... a surrender to fear... or at least a surrender to the concept of Mortality. You're dream self has to learn by repeated experience that it has nothing to fear. You need to stay Dreaming after the Bomb goes off.