The Three Mile Island disaster forced hundreds of thousands of people to evacuate their homes. It absolutely dominated the news cycle. It led to a complete rethinking of nuclear energy. And it all stemmed from a plumbing problem, a valve that didn’t shut. 

But the Three Mile Island accident isn’t the only meltdown caused by a seemingly small issue that snowballed into a gigantic disaster. To find out exactly how this happens, we talked with Chris Clearfield, co-author of “Meltdown: Why Our Systems Fail and What We Can Do About It.”