The nuclear reactor crisis at Fukushima Daiichi has been upgraded to a 7 on the International Nuclear Events Scale. That's the same rating as Chernobyl. It's interesting to me, though, how these two events can share the same rating, but still be quite different in several important ways.
For instance, Chernobyl released a lot more radioactive material (Fukushima has still only released 1/10th of Chernobyl's radioactive output) in a much shorter period of time. The slower pace of Fukushima, combined with the Japanese government's significantly more open and responsive approach, means there have been fewer significant health impacts caused by Fukushima so far.
But the differences don't all work in Fukushima's favor. It's likely to take longer to get this crisis under control, and Fukushima cleanup crews will have to deal with a lot of contaminated water that wasn't present at Chernobyl. Because of that, there's a possibility that these two disasters could look more similar over the long-term view than they do right now.
Nature "The Great Beyond" blog: How Fukushima is and isn't like Chernobyl
NPR: Fukushima vs. Chernobyl — still not equal
