Radiation comes from particles of ionizing isotpes of regular atoms.

U 235 has a half life of nearly the life of the universe.
Plutonium is way into the many tens of thousands of years.

Yep Iodine Cesium and other by products of HOT U 235 -8
Are short lived in comparison.

Iodine does not lose all its radioactivity for years.
But its half life is indeed 10 days. At its peak it can be devestating if injested. Horribly devestating.

poo pooing the hazared is in no ones best interest, unless you are afraid the truth will send people to suicide or hysterical break downs...which ain't likely