Where Cs137 or I131 is measured, hundreds of other hot particles are also present. CS137 and I131 are tracers. One hot particle continues to decay into these hundreds of other isotopes FOREVER wherever it lands. NUCLEAR FISSION NEVER DISAPPEARS, EVER.
8/30/13 #Fukushima Daiichi Cs 137 #Atmospheric #Dispersion #Model (one release from one reactor) from #NOAA