News coverage of the damaged Fukushima Daiichi nuclear power plant gives the impression that fixing it is only a matter of restoring power to the pumps, or otherwise providing coolant (water) link to www.reuters.com --to the radioactive superheated core. But it's likely too late.
Japanese hot-water reactors are built like US nukes. They have two separate loops of water running through them--water that would supply a small river. The outer loop takes heat from the steam that flashes out of the super-pressurized inner loop. When that water stops flowing, temperatures and pressure rise in the reactor core that can easily reach the melting point of steel.
Once a certain threshold is passed, water cannot be added because of the phenomenon of "steam binding." Any water that is introduced toward the inferno is forced backward by insuperable pressure. Should water somehow be inducted, its temperature difference could shatter the containment, depending on the speed of cooling and the degree of neutron bombardment deterioration ("embrittlement") that has occurred during operation.
If the neutron-absorbing rods were fully inserted in the first moments of the quake, they will block further reaction; but if meltdown temperature is reached, the heavier uranium will flow downward and puddle at the bottom of the reactor. Its fission will then be uncontrolled, as in the case of Chernobyl (though that was a supposedly safer graphite-moderated reactor).
And we have prevailing westerly winds here in Oregon....