well from what i have understood from Swedish media is that the cooling have stopped in all reactors from the power-outage. When the existing water in the tanks heat up they start to release hydrogen and the pressure builds up. And then they have to vent it manually and when the hydrogen mix with the oxygen in the air it ignite and explode. That has happened in reactor 1 and 3. And those explosions blew the roof of the buildings. And tonight an explosion in reactor 2 happened which damaged some vital part (condensation-pool is a direct translation from the Swedish word). The fear is that once the water have evaporated the uranium-staffs will be exposed and they will start to melt. After a while they will melt though the bottom of the reactor tube.

Also i heard that the winds have changed towards Tokyo and they now fear radioactive fallout blowing in. They have already measured in increase in radiation in Tokyo. I just hope they all get out of this relative unharmed. Earthquake and tsunami is bad enough. A new Chernobyl would make that look like a picnic. So close to population dense locations.

Agree with KitKat though. Always thought we should pour money in to nuclear power research. Make the plants safer and more efficient and learn how to handle the nuclear waste better. Coal and Oil will never be much cleaner and wind and water just don't provide enough. But as someone have said, "Sure we all want nuclear power, but would you want to live next to one?".