I can recommend Atomic Accidents: A History of Nuclear Meltdowns and Disasters: From the Ozark Mountains to Fukushima by James Mahaffey - it has a chapter on Chernobyl and goes into a fair amount of details:

http://www.amazon.com/Atomic-Accidents-Meltdowns-Disasters-M...

This accident, along with quite a few others, is covered in the excellent book: Atomic Accidents: A History of Nuclear Meltdowns and Disasters: From the Ozark Mountains to Fukushima by James Mahaffey:

http://www.amazon.com/Atomic-Accidents-Meltdowns-Disasters-M...

Edit: The book is no way anti-nuclear and actually starts with a description of a horrific accident at a hydro-electric plant.

In the book "Atomic Accidents" James Mahaffey points out that the Convair B-58 Hustler bomber actually gave off more radiation than the nuclear weapon it carried as its airframe was made of an alloy of magnesium and thorium ("mag-thor")

http://www.amazon.com/Atomic-Accidents-Meltdowns-Disasters-M...

http://en.wikipedia.org/wiki/Mag-Thor

There were two explosions - first was a steam explosion followed 2 or 3 seconds later by another more powerful explosion - with the cause of the latter still being debated. However, one theory does describe it as follows:

"However, the sheer force of the second explosion, and the ratio of xenon radioisotopes released during the event, indicate that the second explosion could have been a nuclear power transient; the result of the melting core material, in the absence of its cladding, water coolant and moderator, undergoing runaway prompt criticality similar to the explosion of a fizzled nuclear weapon."

http://en.wikipedia.org/wiki/Chernobyl_disaster#Experiment_a...

NB I'm in the process of reading *"Atomic Accidents - A History of Nuclear Meltdowns and Disasters: from the Ozark Mountains to Fukushima" - but I haven't got to Chernobyl yet....

http://www.amazon.com/Atomic-Accidents-Meltdowns-Disasters-M...

On a related point - I just finished reading "Atomic Accidents: A History of Nuclear Meltdowns and Disasters" and the author specifically mentions how the "can of soup" shape is pretty dreadful for holding fissile materials:

http://www.amazon.com/Atomic-Accidents-Meltdowns-Disasters-M...