For anyone interested in this topic, I can really recommend "Radiation: What It Is, What You Need to Know" (by Robert Peter Gale and Eric Lax)[1] which includes some very thorough discussion on Chernobyl and Fukushima. An interesting point they raise about Chernobyl is the psychological fallout of people thinking they were exposed: there was a notable rise in abortions and quite a few plant workers drank themselves to death after the accident. It's all very fascinating.

[1] http://www.amazon.co.uk/Radiation-What-You-Need-Know-ebook/d...