Let me preface this with: DON'T TRY THIS AT HOME!
Let me add also: NO SERIOUSLY, DON'T TRY THIS AT HOME!
And this: WHAT PART OF DON'T TRY THIS AT HOME DON'T YOU UNDERSTAND!?
Last week, Richard Handl, a resident of Ängelholm, Sweeden was arrested for attempting to build his own nuclear breeder reactor in his kitchen. He said he wanted to split atoms as a hobby, but now realizes that in retrospect it may not have been a good idea. But don't worry! He had a Geiger counter to measure the radiation.
Fortunately for us he kept a blog of his progress, though he didn't update it very much and it really doesn't seem like he got particularly far at all. From the looks of it, he was still at the relatively early stages of trying to isolate his radioactive elements to a purity he could use for fission.
Getting the materials is the hard part of building a homemade nuclear reactor, way more so than actually building it. Radioactive isotopes are strictly controlled by the International Atomic Energy Association and the Swedish Radiation Safety Authority in his home country, to keep people from doing exactly what Handl was trying to do (or much much worse, build bombs).
Once someone has as much thorium, americium and radium they need, it’s a relatively simple process to make a nuclear reactor.
If it's not the exact same process that Handl was using to make his own reactor, it's pretty close. He linked to it on his blog to illustrate what he was trying to do. However he wasn't the first to try to build a fission reactor at home. This video comes from a film called "The Nuclear Boy Scout" about David Hahn who at the age of 17 built a nuclear breeder reactor in the tool shed behind his mother's house. In 1998, Ken Silverstein writing for the Harper's Magazine documented how a high school kid could set up his own miniature Manhattan Project in his back yard.
Getting trace amounts of nuclear material is startlingly easy; getting enough to build something interesting is quite another matter entirely and requires a lot of forethought and careful planning. A surprisingly large number of easy to come by consumer products contain tiny amounts of radioactive material. Thorium can be found in lantern mantles, radium in old glow in the dark watches and americium in smoke detectors. Through cleverness, tenacity and downright luck in some places, Hahn found ways to acquire enough of all the needed materials to sustain a fission reaction and in the process get his mom's back yard declared an EPA superfund cleanup site in the process.
It looks like Handl was in at least some way inspired by Hahn. Handl had one advantage over Hahn, the internet! He said that he bought most of the radioactive materials he needed over eBay. At the same time, it's clear that Handl's lack of forethought about the project was his undoing. Handl was arrested and shut down five months into the project after he realized that what he was doing might be against the law. He contacted the Swedish Radiation Safety Authority to see what the law said about playing with nuclear fissile materials in his kitchen. Shortly thereafter the police showed up and led him away.
Really though, if he wanted to play around with high energy physics in the comfort of his own home, fusion is the way to go. It's safe, it's the way of the future (fission is so 1942), and it glows! Last year Mark Suppes became the 38th person to build a homemade working fusion reactor… right in the heart of Brooklyn. Wait a second, isn't that exactly the plot of Spiderman 2?