Japan has updated the the threat level from the Fukushima Plant from five to seven. And while everyone ought to put Fukushima into context, chiefly by looking at the damage facing the rest of the country, we can also see that, broadly, things worked as expected at the power plant. They just did not build the plant to survive the 48ft-high tsunami waves and 9.0 earthquakes that happen perhaps once every thousand years. Very poor planning indeed.
This is an older, albeit by a few weeks, graphic from the New York Times explaining how a reactor is ‘shut down’ and then, failing that, what a meltdown is. And most importantly, how the meltdown of a modern reactor design is far different from that at Chernobyl.

Credit for the piece to Xaquín G.V., Bill Marsh, Dylan McClain, and Graham Roberts.