Pinkie Pie Guide to Building a Fusion Reactor · 12:26am Mar 4th, 2019
Anyone see this story in the news a couple of weeks ago about a 12-year old who built a fusion reactor? This is a well-established DIY project. The design is a Farnsworth-Hirsch fusor, which uses high electric fields to force hydrogen atoms into fusing together. There is a whole community of fusion fans building reactors in basements and garages around the world. Sadly such devices are not at the scale required to solve the world’s energy crisis. That challenge is being taken up by large international collaborations such as the ITER project.
Let’s get Rainbow Dash and Pinkie Pie to talk us through this. (Read Rock Farms and Nuclear Reactors first).
What is nuclear fusion Pinkie?
Well, y’know how nuclear fission is when a really big fat nucleus like uranium-235 splits apart and kicks out neutrons, which go on to hit other uranium atoms and cause them to split apart and create a chain reaction.
Yeah…
Fusion is the opposite of this. We get two really little nucleususes—like hydrogen—or better deuterium and tritium—DT—and fuse them together—
Deuter—what?
Deuterium is made of a proton and a neutron, while tritium has a proton and two neutrons. Fusing them is kinda tricky as the protons have a positive charge and positive charges repel other positive charges so it’s really hard to get them close to each other. You give them a gentle push and they just fly off in another direction. But if you force them to make the effort and get them really close together so they tunnel into each other hearts, then they feel the strength of the strong nuclear force and they realise how sweet it is to be bestest friends and they remain stuck together forever. Unless you try really hard to pull them apart! And forming this new bond of friendship makes them all warm and happy and giving out lots of energy. Except some of the neutrons are a bit more wild and free and fly off.
Can you build a reactor to do that?
Yes, if you gimme a vacuum-tight chamber, a really good pump to get all the air out, a high voltage power supply to make a big electric field, some steel wire, insulating tape, a good soldering iron, pair of pliers, some snacks, and a friend or two to help. But seriously Dashie, baking cupcakes is just as much fun, and has the bonus that the end you get a load of cakes to eat, while all a little fusor would do is spit out a few neutrons. Or you could get a glowing plasma, except you would need to make as window in your chamber to see it, which makes it a bit more work.
Can’t you make a big fusion reactor to generate energy like your fission reactor?
What? A fusor big enough to kick out more energy than you feed into it? That wouldn’t fit in my basement.
Why not?
That’s like making a small sun. You would need to make the plasma really really hot, like a few hundred million degrees hot. You would need a really big tokamak (or doughnut) to keep it in, made of super strong materials to withstand all the neutrons flying out. Nopony has been able to do that yet.
OK. Let’s go for cupcakes instead.
All you have to do is take a tokamak reactor,
Add a DT mix,
Now to up the plasma power gain factor
Compress the field in a pinch,
Making this feat, sure ain’t a cinch,
At a hundred million Celsius,
Easy it is not, to keep it this hot,
But you’ll make your friends envious!
Fusion! Got great potential!
Fusion! Still experimental!
Fusion! Fusion! Fusion! FUSION!
[It's a work in progress.]
More on fusion research:
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You dont need to build it big, you just need to build it so it has a gain better than 1. Then just like houses and cars, you build a few billion of them.
The bigger ones, the shielding I considered for my high pressure double acting compression ignition fusion reactor, was to force a metre or so of liquid hydrogen to flow round the inside of the cylindrical chamber. Supercooling, shielding, fuel breeding and reaction damping. Its safe because its designed to blow up. a hundred times a second. Any weak designs are just trying to cut costs you wont have to consider after because get fusion working properly and you can move to post scarecity. Especially if you build the design using as little high tech stuff as possible.
Impressive about the build. Im suprised that his parents gave him $10 thousand and the room in the house to build it. Closest I could get for a eye dropper cold fusion reactor design was the large buried fishpond in the garden, and palladium wires that sold out within acouple weeks from a company thats now bust.
I still like the idea of replacing the NIFs glass laser with a million Toyota laser sparkplugs. Pity theres not the market for ICE vehicles to support the necessary production of such lasers any more.
That is, given it gets exponentially harder to make a stable reactor the bigger you go, why not make an unstable reactor? Billions of explosion driven vehicles cant be all that wrong?
So, this is how the world will end..... By children building tiny nuclear reactors that then explode everywhere. Too bad, I thought it would be zombies.
Clever song at the end
Nice
5022657
It's a great vision, but I've not read any convincing proposal for micro fusion reactors. This seems to be the reason fusion is always 20-30 years in the future. Industry would like a small scale project to demonstrate feasibility. But it's only feasible on a huge scale, which comes with all the risks of any big project. It may be commercial fusion reactors are not economically viable, but the potential benefit is so great, it's worth researching through projects like ITER and NIF.
5022658
Trouble is, it's hard to think of any way you could get a fusor to explode. Anything that causes damages will immediately cool the plasma and stop the reaction. Writers looking for a plot where a teenage nerd causes the end of the world would probably do better going for the trope where they hack into a military computer system. Or zombies.
5022696
I learnt my song writing skills from the best.
5022739
Thanks
Last I heard tokamak research was at a hurdle. Might have better luck with LENR at this point. I am reminded of an "ecat" device that I heard about years ago, which a friend of mine (happening to have been a Nuc) commented on the presence of Lithium-6 in the modified nickel/hydrogen design. Heard about it back in 2014,wonder if there's been any progress on that avenue...
Sure, such a reactor could meet our energy-needs. The simplest way is to scale it up to the mass of 2*10^29 KG.
5022824
Good, because zombies are much cooler! And a more realistic scenario, too.
5022825
LENR? Isn’t that just another name for Cold Fusion? Nope, no progress there.
5022841
. I correct my previous statement that it’s hard to think of any way you could get a fusor to explode
Just don’t go more than
onetwo orders of magnitude above that or it might explode5022948
1 order of magnitude larger is the mass of Sol:
Sol is 2*10^30 KG. The smallest stars are under 2*10^29 KG.
5023097
Well I failed that test.
5023361
Well now, you are not an AstroPhysicist. A star with the mass of 2*10^29 KG should live about 10^13 years. as these stars die, gas between galaxies (each Hubble-Sphere will only have 1 supergalaxy, with a mass of about 10^50 KG), which is currently suspended between galaxies by light-ppressure will fall into the supergalaxies and form the last stars. By 10^15 years from now, it will be extremely unlikely to find even 1 live star anywhere in the Hubble-Sphere of the supergalaxy which will be the result of galaxy-merger. The universe will be dark and dead. That is very sad. Maybe, you can write a story about immortal alicorns in a dying universe set 10^13 years from now (when the red dwarves will die).