en.wikipedia.org...
Potassium Iodide (chemical symbol KI) can be used as a defense against radiation from iodine-131. From that wiki link, and another I looked at, it
appears that KI is useful only against that one kind of radiation, though that type is present in most nuclear weapons other than the 'dirty
bomb'.
Also note that regular iodine (used as a disinfectant, among other things) is NOT a substitute for potassium iodide, and drinking iodine would be an
incredibly stupid thing to do under any circumstances.

