Fukushima Reactor 1 melted down, 2 and 3 may have too

Ars wrote Fukushima Reactor 1 melted down, 2 and 3 may have too.

"Things moved fairly quickly: by four hours after the tsunami hit, the levels of cooling water had dropped enough that the top of the fuel stack was exposed to the air. Shortly after that happened, the temperature in the core reached nearly 3,000°C, and the cooling water boiled off the bottom of the fuel stack. Melting of fuel rods started at 4.8 hours after the earthquake hit, and a partial meltdown had already occurred by 5.1 hours. According to TEPCO, any residual integrity in the fuel rods was gone by 15 hours after the quake, and the reactor core was emptied of fuel by 16 hours. If there's a bright side here, it's that, by melting to the floor of the reactor, most of the fuel was resubmerged in cooling water"

"All of this will make the cleanup efforts extraordinarily complex, as the fuel can no longer be lifted out using the structure it was incorporated into, since all that supporting material has melted away. Workers will also have to contend with leaks of highly radioactive water during the process; that water will have to be removed or contained before it leaches into the surrounding soil. There are positives here—temperatures are relatively low now, and the fuel appears to have remained in the reactor vessel—but Fukushima is likely to be a long-term worry."