As far as I can tell, neither the Japanese government, nor the operating companies tell the truth.

Here’s my take of the story:

  • The tsunami not only destroyed the generators, but the complete cooling systems.
  • Thus, the cores will overheat and melt, they have no way to prevent this, they can only try to keep the damage as low as possible.
  • The cooling water turned into gas and disassociated into hydrogen and oxygen. Unfortunately, this is highly explosive. So the best they can do is to try to get the gas out of the core containment, and let is explode outside where it does not cause too much radioactive pollusion (are core explosion would be really bad). This already happened at reactors 1 and 3, and will happen at reactor 2 the next one or two days.
  • They use the sea water to slow down the core meltdown and keep the core containment stable. They probably do this by flooding the second containment, where there it no direct radioactive materials.

So essentially, I don’t see much of a risk of a nuclear explosion, and I expect the radioactive pollution to be quite low, mostly via indirect radiation from the coolant in the outer containment. The reactor however is trashed and full of highly radioactive waste, that will require constant cooling for the next few years.

However, I’m really concerned that apparently, the government and the companies involed lied to us. This is happening a lot when it comes to nuclear power, they barely are truthful about what is happening.

Nuclear power is only safe as long it is operated by altruistic and responsible people. Once you bring free market, politics and money in, it is a dangerous toy that should not be toyed with by humans.