The Japanese Chernobyl?

It is starting to appear more and more like it. Three reactors have suffered at least partial meltdowns. The water in a pool holding spent fuel rods is boiling off. Other reactors were shut down following cooling failures. Because of the loss of generating capacity, there are now rolling blackouts in Tokyo which may continue for quite some time.

These are boiling water reactors, which means that the steam that turns the power turbines is directly produced by the nuclear fuel. If you have ever used an immersion element to boil water in a cup, that's kind of the idea. Except that unlike that immersion element, a reactor can't be fully shut off. When a reactor is shut down, it still generates a level of heat that has to be moved out of the reactor.

Radiation levels in the vicinity of the generating plant are at 400 millisieverts per hour. If you were raised during the Cold War, that's roughly equivalent to 40 rads/hr. That's about a fifteenth of the dose that will likely kill someone with medical care. There's also evidence that a person will survive a large dose of radiation (like 1,000 rads) if it is broken down into smaller dosages over time, with rest periods. Not that you'd want to try that.

Should radiation levels begin to rise, then the remaining workers may have to be removed, or they will be working with the real possibility that they are giving their lives for their country. There may be no choice other than to ask engineers to keep working, for what would happen otherwise would not be very good, especially if the wind shifts to the northeast and radiation is carried to Tokyo and Korea.

For all of the bashing that nuclear power has taken, I do not know of an alternative that would work for Japan. Building more plants that run on geologically compacted biowaste is not an answer, not as oil is over $100/bbl. Burning coal is incredibly bad for the environment, even if you don't believe that releasing more carbon into the atmosphere is a problem. Wind and solar have reliability problems and I've not seen where solar power has shown that it can scale up. Geothermal might be a possibility, but my understanding is that the hot water/steam that comes up from the Earth then has to be replaced, which would be a form of hydraulic fracking,* and that might not be good in an earthquake-prone region.

As for fusion power plants, well, fusion power has been "twenty-five years away" for the last forty years. And if you think that fusion won't have its own unique set of serious radioactive waste problems, then I have a bridge to sell to you.
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* Which is considerably different from "frakking".