Picture of Build A Fusion Reactor
Yes, you can build your very own nuclear fusion reactor in your house! But first, a few warnings:

-This project includes lethal voltage levels. Make sure you know your high voltage safety or have a qualified electrical advisor.
-Potentially hazardous levels of x-rays will be produced. Lead shielding of viewports is a must!
-Deuterium, an explosive gas, will be used. Make sure to check for fuel leaks.
-All the other inherent dangers of a home engineering project of this degree (a wide gamut of potential injuries, damage to the checking account, and the loss of general sanity)

Here are the minimum required materials:

-A vacuum chamber, preferably in a spherical shape
-A roughing vacuum pump capable of reaching at least 75 microns vacuum
-A secondary high vacuum pump, either a turbo pump or oil diffusion pump
-A high voltage supply, preferably capable of at least 40kv 10ma - Must be negative polarity
-A high voltage divider probe for use with a digital multimeter
-A thermocouple or baratron (of appropriate scale) vacuum gauge
-A neutron radiation detector, either a proportional He-3 or BF3 tube with counting instrumentation, or a bubble dosimeter
-A Geiger counter, preferably a scintillator type, for x-ray detection and safety
-Deuterium gas (can be purchased as a gas or extracted from D2O through electrolysis - it is much easier and more effective to use compressed gas)
-A large ballast resistor in the range of 50-100k and at least a foot long
-A camera and TV display for viewing the inside of the reactor
-Lead to shield the camera viewport
-General engineering tools, a machine shop if at all possible (although 90% of mine was built with nothing but a dremel and cordless drill, the only thing you really can't build without a shop is scratch building the vacuum chamber)
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JoshWolff73 months ago

I am really interested in this and would love to build it. Is it possible to hook this up with thorium instead of deuterium? How can I simplify this project? Is this fusion reactor hooked up to a capacitor or something of the like that it charges - how is the power harnessed?



Thorium is much more stable so it is harder to fuse. At this scale probably not.

Would would also need to pump in even more power than the deuterium would need in order to get a reaction if it were even possible.

How is the power harnessed?

The most likely way you would harness the power would be to use the heat coming off the reactor to drive a thermal process, probably with water becoming superheated steam to turn a generator turbine.

SobhanB JakeV29 days ago

Can you please explain what's the point? I don't think the efficiency of all this is 100%. So aren't we just using a lot of voltage to produce less voltage?

JakeV SobhanB29 days ago

Ultimately the idea would eventually be to use a fusion reactor to produce more power than it requires to run, but that's not what it's capable of right now.

Why bother doing this at all?

Even if it's not producing more power than it takes in, it still has its uses. I don't know about how useful it would be for home projects, but it does make a powerful neutron source for various kinds of analysis.

For examples of neutron spectroscopy, see

You're talking about a very different nuclear reaction. Deuterium is hydrogen with an extra neutron attached to it, and you get two Deuterium atoms colliding with each other to create heavier Helium atoms, releasing lots of energy in the process. This process is called nuclear fusion.

For Thorium, the reaction is nuclear fission. Take Thorium, bombard it with neutrons to turn it into radioactive Uranium, and the Uranium undergoes a chain reaction dropping off Helium nuclei and eventually leaving you with lighter lead.

Fusion creates heavier elements, fission destroys them.

Oh ok! I got it! Thank you for taking your time to explain that.

christensent (author)  JoshWolff73 months ago

No thorium, can't really be simplified much, no capacitor, and no power harnessing

can we set it up to use ( I hope I spell it right ) helium ( my spelling sucks )?

christensent (author)  ElectricBlue1232 months ago

No, deuterium and tritium are the only gasses that will produce fusion in a DIY fusor. Deuterium is the only one that is legal to use.

Can the valve be manual ones? I prefer to use manual (for simplicity) but can high voltage be dangerous that I shouldn't use a manual valve? I'm not familiar with pneumatic valves or other type of valves.Thanks in advance.

ty by the way

what there are resticshens ??? wich counchery is that ? ( sorry for spelling ) and can we use magnets to control it so make a ( by way of trikel filling and emtiying ) a sustand fusion reactor?

Thank you!

caolandix12 days ago

Hello, I am looking to purchase HV power supply to start building this and they wanted to know what frequency it should be. I have no idea what to tell them as I am new to this field of physics. I explained to them that Ia m a graduate student focusing on plasma physics with an interest in fusion.

Here's a link to the PS I was lookign at:

pienapple2720 days ago

Did you build an external grid or did you connect the chamber itself to ground potential ?

kodama10 months ago
Still in the early stages of researching this. Can they be modified to harness generated power?
JakeV kodama29 days ago

Getting physical breakeven is something physicists have been working on for many decades -- they still have to pump in more electrical energy than they can extract out of it, even in the most sophisticated reactors.

crob0910 months ago
Maybe a dumb question but how's a Fusion-Reactor used to produce electricity, isn't it threw steam generation?
If it is, the how can the Reactor be deemed efficient, or is efficiency in this case a measurement of something else?

Very cool project!!!

This reactor has a massive net loss of energy. It doesn't have much of a use other than having your own star :)

It has a great use as a neutron radiation source, if you have any use for that. Neutron spectroscopy is a powerful analytical tool that lets you get a good look at a full range of molecular dynamics, unlike the restricted molecular dynamics you can tease out of FTIR and Raman spectroscopy.

ARahman1777 months ago

Would an air diffusion pump work instead of the oil diffusion pump or would it have to be oil or turbo?

It has to be some kind of hi-vac pump. Oil, turbo, or cryo. Diffusion doesn't work at hi-vac, because the gas molecules aren't interacting in such a way you can get diffusion, they act more like ballistic particles at hi-vac pressures.

christensent (author)  ARahman1777 months ago

I don't know, not familiar with that. If it reaches similar pressures and pumping rates as an oil diffusion pump, sure. I think that might be for higher pressures though.

when you say at least 75 microns do you mean anything below it...would a 25 micron vacuum pump suffice?
christensent (author)  ARahman1777 months ago

75 microns would get you a demo fusor, but no fusion. You really need a pump that will get you <1 micron and then you backfill with deuterium up to about 10 micron to run. And a super nice mechanical pump that says 1 micron will not work since that is an ideal measurement, and also it has no pumping speed at that pressure.

thanks for the info...where did you get the two pumps that you used in this reactor?
christensent (author)  ARahman1777 months ago

Ebay... just about everything for a project like this will come from ebay unless you have tons of money to blow on nice new stuff

What roughing pump did you use in this reactor

Would There Be A Chance Of It Working, If It Was Built On A Bigger Scale, And Would It Be Able To Power A Ship That Has A Maximum Speed Of 5000 MPH.

It works, it creates fusion, but it does not output more power than it draws. Its use is more likely to be found as a neutron radiation source. Scientists with much bigger, much more sophisticated equipment have yet to run a fusion experiment in a lab that produces more power than the electricity put into it. So far the sun is the only fusion reactor we can get significant amounts of power from.

As to powering a ship capable of going 5000mph, in the water that's basically impossible so far, as you run into the problem of cavitation behind the boat. The technique for going faster has always been to make a boat that has a smaller water profile to make cavitation smaller, and the fastest they've ever gotten was around 320MPH. A more reasonable and usable boat likely has a physical speed limit of around 50MPH before cavitation presents a hard limit to the speed. The problem isn't getting MOAR POWER, it's mostly solving hydrodynamic problems.

ARahman1773 months ago

how did you shield the viewport with lead exactly

You can buy leaded glass.

bigdyl1231 month ago

I would like to know how to make your vaccum chamber. i tried looking for hemespheres and i cant find any. think you can point me in the direction for parts?

pienapple271 month ago

I was just wondering, because of the chamber materials, how hot does it actually get when the reactor is operating? Is it safe to attatch a glass viewport to one of the chamber flanges?

Marsh1 month ago
In physics, the first thing we check are the units. You appear to be citing microns as a measure of vacuum, when it is actually a measure of distance. If this is an error, can you correct it? If not, can you explain?
christensent (author)  Marsh1 month ago
When discussing vacuum pressure, microns refers to microns of mercury

how much tritium does it produce? and can you please tell me how much neutrons are emitted?

adityayo632 months ago

What valve do you recommend for the one between diffusion pump and vacuum chamber? I've looked through ebay and leskers but I couldn't find a kf flanged gate valve that is bellows sealed under $150. Many on recommends a gate valve that is bellows sealed but it is way too expensive.

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