spaceSpace and Physics

The "Radioactive Boy Scout" Who Built A Nuclear Reactor In His Back Yard


Dr. Katie Spalding

Katie has a PhD in maths, specializing in the intersection of dynamical systems and number theory.

Freelance Writer

scout badges

David Hahn wanted to earn his Atomic Energy scout badge  so, naturally, he built a nuclear reactor in his back yard. Image credit: Mike McDonald/, Fast_Cyclone/, IFLS

Everybody needs a hobby, right? Something to stave off boredom, improve your mental health and abilities, and help your social development. Hobbies are great.

Just … try to choose one that doesn’t get you arrested for possession of an atomic bomb.


In 1994, David Hahn was a 17-year-old Boy Scout from Michigan with an interest in science. Seven years earlier, he had been given a book: The Golden Book of Chemistry Experiments, and he had been hooked ever since.

“Big deal,” you might be thinking, “I’ve always loved science too – that’s why I’m currently on a website called I Fugging Love Science dot com.”

But here’s the difference: where many people express their love of science by sharing fun memes or politely trolling Bill Nye on social media, David Hahn – well, David Hahn built a breeder reactor in his back yard.

A breeder reactor is a type of nuclear reactor that generates more fissile material than it consumes. That might sound impossible, but breeder reactors have been around and functioning, more or less, for 75 years now. It works using a core of plutonium-239 surrounded by a blanket of uranium-238: as the plutonium decays, and its lost neutrons are absorbed by the uranium. This transforms the uranium-238 into uranium-239, a highly unstable uranium isotope that very quickly decays into neptunium-239 through beta decay. This neptunium isotope is more stable than uranium-239, but still only has a half-life of about 57 hours: another round of beta decay turns the neptunium-239 back into plutonium-239, which is used to replenish the fuel core.


If you think all that sounds way too complex for a boy scout to be messing around with in his mom’s potting shed, you’re not alone. Hahn was arrested in August of 1994, when police found what they thought was a “potential improvised explosive device” in the trunk of his car (that wasn’t hyperbole in the introduction), and he very quickly found himself in trouble with not just local police but the US Department of Energy, the US Nuclear Regulatory Commission, the FBI and the Environmental Protection Agency (EPA). An investigation of his car by the Michigan State Police Bomb Squad and State Department of Health had found high enough concentrations of the radioactive materials thorium and americium to automatically trigger the Federal Radiological Emergency Response Plan; upon being interrogated, Hahn explained that he simply wanted to obtain his Eagle Scout badge.

When state radiological experts examined Hahn’s lab (aka his mother’s potting shed), they found levels of radioactive material that registered 1,000 times higher than normal background radiation. The shed, according to the Department of Public Health, contained materials regulated under federal law, and by 1995 the EPA had officially concluded that the shed “[presented] an imminent and substantial endangerment to public health”, and that his safety precautions – a couple of signs saying "caushon" and "radioactve" – were, let’s say, insufficient.

Because of the danger, Hahn’s lab was dismantled in June of 1995 under a law originally designed to deal with one of the most devastating environmental disasters in US history. The materials he had gathered for his experiments were loaded into barrels and taken to the middle of the Great Salt Lake Desert in Utah, where they were buried beneath the sand.

Well – that’s what happened to the materials they found, at least. Hahn would later reveal to Harper's magazine that his mom had gone to the potting shed and removed his most dangerous experiments before the officials ever reached them. Unlike the EPA, she found vials of radium, pellets of thorium, radioactive powder, and a working, home-made, neutron gun – and unlike the EPA, she disposed of them not in a specialist repository in Utah, but in the trash.


“The funny thing is,” Hahn told Harper's, “[the EPA] only got the garbage, and the garbage got all the good stuff.”

 This Week in IFLScience

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