Growing up in suburban Detroit, David Hahn was fascinated by science. While he was working on his Atomic Energy badge for the Boy Scouts, David's obsessive attention turned to nuclear energy. Throwing caution to the wind, he plunged into a new project: building a model nuclear reactor in his backyard garden shed.

Posing as a physics professor, David solicited information on reactor design from the U.S. government and from industry experts. Following blueprints he found in an outdated physics textbook, David cobbled together a crude device that threw off toxic levels of radiation. His...