danalwyn

So the BBC is reporting that the reactors at Fukushima have finally entered cold shutdown.

As you may remember from thousands of panic-stricken stories back during the days after the earthquake, even with the reactor dampened, the fuel rods are still glowing hot, and have to be continually cooled lest they wake up again and restart the reaction. This is done by basically pouring water on them, letting the water boil off, and then condensing that steam with other water in a separate system.

In cold shutdown the temperature of the rods has dropped below boiling, which means that instead of having to cycle your coolant you can basically fill the reactor chamber and wait - no pumps or machinery necessary (well, not much). This is the successful end state to a reactor shut down.

So everything turned off after nine months (as I recall was predicted), and the reactor vessels did not catastrophically explode. And statistically, nuclear probably remains safer then most fossil fuels. But maybe only thanks to an averted catastrophe.

At least Japan can breathe easily again.