DIY Fusion—Makeshift
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Building a mini nuclear reactor in your home requires only spare parts and basic physics

— DIY Fusion

Call it extreme DIY. Across the globe, handfuls of “fusioneers”—engineering hobbyists and amateur physicists—are building nuclear fusion reactors in their basements and backyards. They’re driven partly by the thrill of tinkering and partly by the promise of solving one of the world’s biggest problems: how to create clean, carbon-free energy on the cheap.

In nuclear fusion, atoms are forced together at high temperatures and pressures, a process that releases energy. According to, the main hub for fusioneers, nearly 60 people have achieved nuclear fusion from a homemade reactor—the youngest of whom is just 14 years old. Building a tabletop nuclear plant involves lethal electricity voltage levels, explosive gases, and potentially hazardous x-ray exposure. But it doesn’t require plutonium or uranium. Here’s an abbreviated guide adapted from our friends at Instructables:

Get a vacuum chamber
Shop eBay for a spherical vacuum chamber, which pumps out air and other gases to create a low-pressure environment. Or scrounge for parts—including two steel hemispheres, eight-inch rims called “flanges”, and bolts—and weld them together using tungsten inert gas.

Prepare the vacuum pump
Find a diffusion pump, fill it with low-vapor oil, and connect the pump’s inlet to a valve on the vacuum chamber. This will lower the chamber’s pressure (making it a stronger vacuum). Then attach the diffusion pump to a mechanical pump, which will remove gas molecules.

Build an inner grid
Assemble your electrical wires, preferably ones made of tungsten, since the metal has a high melting point. Attach the wires to a high-voltage (around 40 kilovolts) electrical feedthrough. Don’t get zapped.

Assemble the Deuterium system
Select a fine tank of deuterium from your cellar of dangerous and explosive gases. Attach a high-pressure regulator directly to the tank; this will keep the flow of gas at a safe pressure. Add a needle valve to more precisely regulate the gas flow. Connect this all to the vacuum chamber.

Configure the power supply
Snag a high-voltage power supply module on the web. Take the negative voltage output and attach it to the chamber, and throw on a large ballast resistor, which will limit the amount of electrical current flowing through the circuit.

Set up the neutron detector
To prove you’ve fused atoms, you’ll need to detect neutron radiation. The easiest and most accurate way to do this is with a “proportional tube”. You can buy ones filled with BF3 or Helium-3 gases and attach a counting device. This will detect electrical pulses each time neutrons pass through the tube. These tubes are extremely expensive, so fusioneers have created their own versions.

Let’s fuse
Ready? Turn on the mechanical pump and oil diffusion pump, and wait for it to warm up. Throttle the valve that connects the pumps to the vacuum chamber, and gently open the needle valve to the deuterium gas tank. Flip on the power supply. Keep pumping gas and adding pressure until you detect neutron radiation pumping through your tubes. Congratulations! You’ve just fused.

This guide was adapted from an article on Instructables by christensent —



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