Source please?
No proof. Just the source of common sense as I followed this story much longer than most(You have to go looking for such news). You do realize that radiation is still being released there? Here in the us We are being exposed to it every day. And will be for the rest of our lives. Yes it is a “Small Amount”... And the question of will it hurt us is at best unproven.
Some proof of recent criticality has even been discovered in Japan in recent days.
Could this be something else sure. But until proven otherwise then I will speculate on the most obvious.