The journal Nature is publishing several articles today looking at the long term impact of the nuclear disaster at Fukushima in Japan. They're all available to the public.

One news report considers what it will take to fully decommission the damaged plant, a process that could take more than a decade,

After the tsunami on 11 March knocked out backup generators — preventing cooling water from circulating around the hot cores of reactors 1-3 — the fuel rods inside began to warp, split and at least partially melt. Steam reacted with the rods' outer sheath of zirconium, creating hydrogen gas that caused a sequence of massive explosions (see Nature 471, 417-418; 2011).

But data from Japanese regulators and TEPCO suggest to some researchers that conditions inside the core could be far worse than a partial meltdown. Some believe that molten fuel may have flowed into the outer concrete containment vessel, whereas others suggest that nuclear chain reactions are still happening inside the fuel.

One looks at the impact of long-lived cesium-137,