This is a rediculous idea.  Again, nuclear power industry accidents across all of the history of the world do not exceed the amount of radioactive material that is launched into the atmostphere by the worlds coal plants in a single year, and we have been burning coal for almost 200 years, and seriously powering industry with it for over 100 years.  Modern nuke plants don't really 'blow', and even if 100 of them had leakage accidents similar to what happened in Japan (very, very unlikely) we still wouldn't exceed what humanity has already dosed our environment with over the past 100+ years.  That plant had a quadruple redundant emergency cooling system, which we now know isn't quite good enough for a 1:10K year tsumami wave.  It's certainly more than enough for a global economic breakdown, since the idea is to give the enginneers time to put the reactor and hot fuel rods into a longer term stable state.  For some designs (undamaged) this simply involves lowering a neutron shield that waits inside the reactor, and the heat level will slowly reduce to the point that additional water supply is no longer pressing.  For some designs this actually requires that some (all?) of the hot fuel be removed by very well trained operators and placed into open storage pools, with or without neutron shielding between the rods.  Most of the open storage pools are not designed to collect rainwater for level maintaince, but do you really think that should it become obvious, the engineers can't arrange such things for most or all of the power plants?

Furthermore, not all radiation, or radioactive materials, are equal risks.  There is a persistant background radiation in our lives that is completely natural, and it's certainly higher than a layman would assume.  All concrete is mildly radioactive for the same reason that all coal is mildly radioactive, because all rocks contain some trace amount of thorium.  It's just that common.