The mantle in gas lanterns, the small cloth pouch over the flame, is coated with a compound containing thorium-232. When bombarded with neutrons it produces uranium-233, which is fissionable. David bought thousands of lantern mantles from surplus stores and blowtorched them into a pile of ash.
To isolate the thorium from the ash, he purchased $1000 worth of lithium batteries and cut them in half with wire cutters. He placed the lithium and thorium ash together in a ball of aluminum foil and heated the ball with a Bunsen burner. This purified the thorium to at least 9000 times the level found in nature, and up to 170 times the level that requires NRC licensing.
Teenager builds fission reactor in Mom's shed out of household parts. Seriously.
