Facts about Japanese nuclear reactors

fukushima damage left, unit 3, right, unit 4

News reports about the after effects of the Japanese earthquakes and tsunami, particularly the damage done to and efforts to contain the nuclear reactor at Fukushima are everywhere. Many people are panicking that they will be irradiated, die or start to glow an unpleasant green colour. Facts about what is going on are really important and I came across an MIT blog helpfully titled the “MIT NSE Nuclear Information Hub” which contains facts about the science of much of what is being reported and what isn’t. One good starting point is a modified version of a post published by Dr Josef Oehmen which Dr Oehmen transferred to MIT’s Nuclear Science and Engineering Department to review and edit (the original post was titled “Why I am not worried about Japan’s nuclear reactors“). By way of background here (when it comes to publishing correct facts, credibility is critical):

I am a mechanical engineer and research scientist at MIT. I am not a nuclear engineer or scientist, or affiliated with Nuclear Science and Engineering at MIT, so please feel free to question my competence. The text is based on an email that I send to family and friends in Japan the night of March 12. It was posted on this blog by my cousin Jason, went viral and has been equally popular with people who hate it and love it ever since. It aimed at explaining the events surrounding the Fukushima Daiichi-1 reactor. Great lengths of the text are dedicated to explaining how the reactor works, what the different types of radiation sources are, and what safety features have been implemented. I then continue to describe how these safety features were operated to secure the reactor. To the extent that I could, I have verified this information with experts in the field, while the responsibility for any errors remains with me. The version on mitnse.com is the most accurate, and as you can tell in many parts different to the version that appeared here on Jason’s blog. This post is not keeping track of or explaining events after Mar 12. Events kept developing, and many people keep sharing their discovery with me that one is always smarter after the fact.

The edited post is fairly detailed but written in plain language. It is a fascinating read and explains how the Fukushima reactor was designed with multiple catastrophes in mind (although the magnitude of the catastrophe which befell Fukushima was beyond the engineers’ expectations).

One of the important paragraphs in the post is this one:

It is worth mentioning at this point that the nuclear fuel in a reactor can never cause a nuclear explosion like a nuclear bomb. At Chernobyl, the explosion was caused by excessive pressure buildup, hydrogen explosion and rupture of all structures, propelling molten core material into the environment. Note that Chernobyl did not have a containment structure as a barrier to the environment. Why that did not and will not happen in Japan, is discussed further below.

The MIT NSE blog is a tremendously valuable resource and gives some helpful perspective on the drama unfolding in Japan.

Image credit: fukushima damage left, unit 3, right, unit 4 by Derek Visser, licensed CC BY SA 2.0






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