There is a long, easy to read 10 year retrospective of the Chernobyl accident here: http://www.oecd-nea.org/rp/chernobyl/


The short answer: It was bad, very very bad.
But it was not as bad as we thought it would be over the long term.

Keep this in mind as we look to Japan. A reactor with a better design by GE, a better safety system all around, and "total failure mode" for these plant (a full meltdown and core rupture) would not be as bad as Chernobyl in terms of hard gamma radiation exposure to the environment and Iodine 131 and Cesium contamination.

Of course, THREE nuke plants having total failure will affect a massive number of people - the majority of whom have already been evacuated.

There may be no "coming home" for 250,000 or more people here.

I wouldn't be so sure considering that the main fuel for the Chernobyl reactor RBMK design used Uranium instead of the reactor at Fukushima nuclear plant No3 used a mixed oxide fuel (MOX) of Uranium and Plutonium (the most toxic substance known to man).

http://en.wikipedia.org/wiki/MOX_fuel

Plutonium 239 has a half life of 24,200 years compared to Iodine 131 half life of around 8 days and Cs 137 half life of 37 years and Strontium-90 with a half life of 28.8 years.

The area around the Chernobyl plant would become uninhabitable for hundreds of years compared to a MOX release of tens of thousands of years.

As pointed out by others the similarities between Chernobyl and Fukushima units 1,2, and 3 are that both are nuclear reactors. Chernobyl was a carbon pile reactor without any containment and lacking safety systems. The reaction ran away, the carbon pile caught fire, and there was nothing there to keep the escaping radiological mess from leaving. And, no emergency systems in place or readily available way to shut it down, putting out the fire, or contain anything.

The Fukushima units have the core inside a large steel containment, listed as 20cm, ~8", thick, that is itself inside a heavily constructed reinforced concrete shell. Both are air tight and designed to handle pressure. Under the plant is a very thick, specially constructed, concrete slab designed to catch the core in the worse possible meltdown.

So far, as of Sunday, there has been no significant release of radiation. The small amount released would have an effect less than flying cross-country a few times, if that. The ability of the monitoring system to detect these small amounts of radiation is a testament to their extreme sensitivity, not any greatly raised risk.

It is ironic that the earthquake and tidal wave have killed tens of thousands, and made many times that homeless and we are spending time talking about a a situation that has only killed one, killed in the hydrogen explosion, because the word nuclear and the idea of radiation irrationally scares people.

If doesn't matter how many reactors have problems as long as the engineers can contain the radiation, regardless of whether the cores melt down or not. Bottom line for the public is what gets out. Only if a reactor starts spewing high levels of radiation into the surrounding environment does it makes sense to talk about it in the same league as Chernobyl.

I'm with Art. So far, there's so much obsessing about a potential disaster and ignoring the actual humanitarian disaster that we're still just understanding the scope of.

Chernobyl did have Plutonium in its core. It was a breeder reactor designed for Plutonium production. While its initial fuel load out was Uranium, a portion of this Uranium was converted to Plutonium by neutron capture. Any Uranium fueled reactor is going to have Plutonium in it.