This news report:
http://af.reuters.com/article/energyOilNews/idAFTKZ00680620110312
says that they plan on filling the core with sea water, and that this will (through some unclear reaction with the sea water) ultimately shut it down.

there seems to be an important difference between the containment building, which was destroyed, and the nuclear reactor container itself, which, though leaking, is largely intact.

the article claims the explosion was caused by hydrogen gas leaking from the nuclear reactor container, which then mixed with oxygen and caused the explosion.

As I understand it, the concept of these things is that the containment building is to contain leaks etc. from the actual nuclear reactor container, so it appears the "safety" measure of the containment building is gone, and the reactor container itself is damaged and leaking, under great stress, but still largely intact and totally open to the environment.

I suspect that the workers trying to shut this thing down are pretty close, if not beyond, the fatal dose of radiation. I recall the soviet helicopter pilot who make repeated flights directly over the exposed Chernobyl core to drop sand etc. to help contain it. He quickly received the fatal dose, but kept going back again and again.

I totally agree the Japanese government owes everyone a detailed briefing on the amount of damage, the current status of and plans for the reactor.