I'm still working on it whenever I have enough time to breath, it's in a prototypical stage right now. Getting the mushroom cloud to form after the actual plume reached the correct height was the challenge of it, the rest is just refining (i.e. more emitters, scale changes, color changes, particle behavior changes, etc.)
I have tried and failed to make a radiation script however, I'll need to ask someone else to help me out there.