Radiation Cloud Explained: Physics, Water Vapor, Isotopes & Stability

[mishima]

What exactly is a "radiation cloud", as mentioned currently in the news, in a physics sense? Is it just a bunch of super excited water vapor? Is it actually radioactive isotope particles? How stable is it? I can't seem to find any info on the term.

 

[russ_watters]

Yes, for the most part it is water vapor carrying radioactive particles. As for the half-life, someone else will have to help with that...