In the tons of reading material on this topic floating around, I found a very interesting journo article which outlines differences between the Fuskishima situation and Chernobyl.
Article
here .. (apologies if you've already read it).
The main points are as follows:
1. Chernobyl's reactor had no containment structure.
2. Chernobyl's reactors had several design flaws that made the crisis harder to control. Most crucially, their cooling system had a "positive void coefficient," which means that as coolant water is lost or turns into steam, the reaction speeds up and becomes more intense, creating a vicious feedback loop.
3. The carbon in Chernobyl's reactor fueled a fire that spewed radioactive material further into the atmosphere. Fukushima's reactors do not contain carbon, which means that the contamination from an explosion would remain more localized.
4. Unlike Chernobyl, however, a meltdown at Daiichi could end up contaminating the water table.
5. Much of the public health impact of Chernobyl was the result of the Soviet government's attempt to cover up the crisis, rather than moving quickly to inform and protect the public.
6. Emergency workers at Chernobyl took few precautions, and may not have been fully informed about the risks they were taking.
Interesting comparison .. but maybe premature. We don't know enough about what actions have been taken, and under what circumstances, at Fukushima.