The latest information in Fukushima indicated that four of the six reactors are played, some of them very serious. Reactors 1, 2 and 3 are part of the core exposed. This means that nuclear fuel is exposed and therefore lacked the proper cooling to prevent the merger process forward. If this happens, the reaction can be completely uncontrollable and could melt the reactor core.
Explosions, partial melting of the core, fires, removal of radioactive particles into the atmosphere ... The six reactors that form the central Japan, with serious problems from the earthquake on Friday, following its path to nuclear catastrophe. And what many tried to control it gets out of hand.