What Actually Happened at Chernobyl?

In 2007, John Green and his brother Hank ceased textual communication and began to talk primarily through videoblogs posted to YouTube. The videos spawned a community of people called nerdfighters who fight for intellectualism and to decrease the overall worldwide level of suck. (Decreasing suck takes many forms: Nerdfighters have raised millions of dollars to fight poverty in the developing world; they also planted thousands of trees around the world in May of 2010 to celebrate Hank’s 30th birthday.) Although they have long since resumed textual communication, John and Hank continue to upload two videos a week to their YouTube channel, vlogbrothers. Their videos have been viewed more than 800 million times.

This video was so dang fun to research, which, of course, I feel super guilty about because, like, real people died. But, after watching the HBO miniseries, I knew there was more to the science of this. I've also heard a lot of stuff from both credible and non-credible sources that just doesn't hold up to scrutiny. The idea of the "graphite tipped rods" for example is just a simplification for broad audiences. But I've also heard smart folks talk about how RBMK reactors have a positive /fuel/ temperature coefficient, which is not true. No nuclear reactors do, since fuel that reacted more as it got hot would be the kind of thing that would explode every time.

However, for a moment, because water had become such a vital part of the neutron absorption in the reactor, it did have a positive temperature coefficient...meaning that getting hotter made it hotter which made it hotter which made it hotter. That's a coefficient for the entire reactor, and it's due to the "positive void coefficient" where, as the water got hotter, it got less good at absorbing neutrons.

Usually that would be more than counter-acted by the negative fuel temperature coefficient, which is why they thought it couldn't explode...but it was not in this particular circumstance.

----
Subscribe to our newsletter! http://nerdfighteria.com/newsletter/
And join the community at http://nerdfighteria.com http://effyeahnerdfighters.com
Help transcribe videos - http://nerdfighteria.info
John's twitter - http://twitter.com/johngreen
Hank's twitter - http://twitter.com/hankgreen
Hank's tumblr - http://edwardspoonhands.tumblr.com
Listen to The Anthropocene Reviewed at http://www.theanthropocenereviewed.org
Listen to Dear Hank and John at http://www.dearhankandjohn.org

License:
Creative Commons Attribution license (reuse allowed)