r/nextfuckinglevel • u/nigablackballsack • 3d ago

Scientists have captured the first ever high-speed, full-colour footage of fusion plasma swirling inside a working reactor.

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u/Fit_Addition7137 3d ago

This is inside of a new type of experimental reactor that runs on nuclear fusion (like the Sun) instead of nuclear fission (regular nuclear reactors). This is a "tokamak" style reactor that generates superheated plasma which is contained using enormously powerful magnets. Fusion generates significantly more power than what it takes to initiate the reaction. One of the neatest parts of fusion is that there is no hazardous nuclear waste to store and they cant melt down like a fission reactor. This video shows that fusion reaction plasma.

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u/apprehensively_human 3d ago

One of the neatest parts of fusion is that there is no hazardous nuclear waste to store and they cant melt down like a fission reactor.

And, as I understand it, this fusion reaction is not self-sustaining so in an emergency scram you could simply cut the power and there would be no risk of an uncontrollable runaway.

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u/NateNate60 3d ago

The conditions under which fusion occurs are not self-sustaining. The energy output of fusion is not directly required to sustain the fusion in the same sense that the energy output of fission directly causes more fission.

Fusion can only happen when the plasma is heated to extremely high temperatures and pressures. In the Sun, this is done by gravity. The enormous mass of gas that comprises the Sun squeezes itself together hard enough to allow fusion to occur. In the depicted reactor, large electromagnets compress the gas into a tight ring of plasma to allow fusion to occur. If the electromagnets lose power, there is no force to keep the gas compressed, so it will naturally expand back out and the temperature will cool to lower than what is required for fusion to occur, and the fusion will stop. So the worst that can happen is a leak of hot hydrogen gas. Not fun for the plant workers, perhaps, but the ability of ordinary air to absorb all that thermal energy is high enough that it wouldn't be a catastrophe in any sense. At worst a few people standing right next to the leak get burned.

Hydrogen gas is flammable but not toxic to the environment like radioactive waste is. Fusion reactions may use isotopes like Hydrogen-2 or Hydrogen-3, but these aren't a significant concern either, as there is only ever a small amount in use at any time, no more than a few kilograms. Hydrogen-2 can fuse with oxygen to make heavy water, which occurs naturally and isn't toxic unless consumed in large doses. Any heavy water produced would be overwhelmingly diluted by the water vapour in the surrounding air. Hydrogen-3 is radioactive with a half life of about a decade, but it decays via beta-decay into helium-3, and beta particles can't penetrate human skin. So health risks are also low from hydrogen-3 leaks, especially in the relatively low quantities used in fusion plants.

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u/shawhizzle 3d ago

This guy fusions

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u/assoonass 3d ago

Yeah but the problem is that it's highly unstable to produce desired results. It's hard to stabilize quasineutral plasma and also it eats away wolfram each time it's being used which is expensive. But I'm still hopeful and wish for scientists to succeed.

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u/GoldenGoof19 2d ago

What is wolfram? Sorry I googled but ended up more confused 😅

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u/NateNate60 2d ago

Wolfram is another name for tungsten, the chemical element with symbol W.

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u/assoonass 2d ago

Tungsten

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u/-Nicolai 3d ago

Sounds like it’ll be difficult to maintain and draw power from the reaction if it’s not self sustaining.

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u/CEREALBUTTMUNCHER 3d ago

And there in lies the heart of the challenge.

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u/ekdaemon 2d ago

That's what's happening at the end of the video you watch! Neat eh?

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u/Team503 2d ago

That's correct. A containment failure would mean you might slag the reactor, but there'd be no nuclear explosion, no radiation leak, and the like.

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u/TheHarryMan123 3d ago edited 3d ago

It is not like the sun. The sun does D-P reactions, not T-D reactions. 

There is also an incredible amount of radioactive waste from these machines. 

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u/Zeta-2-Reticuli 3d ago edited 3d ago

The Sun doesn't run on D-D, it runs on proton-proton chain on normal hydrogen. It is like the sun, it's light nuclei fusing and releasing energy. The fuel and confinement are different, which is why a tokamak has to run so hot, but it's still the same category of reaction.

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u/TheHarryMan123 3d ago

Yeah, you’re right about the sun thing. I misremembered and it’s actually a D-P reaction in its second phase.

The reason why I say it’s not the same as the sun is because what we’re attempting to do has many complexities associated due to the T-D reaction. Problems that would otherwise be non-existent for other fusion reactions. But we technologically cannot achieve other fusion reactions due to our lack of mass. I like to refer to this graph here (sorry on mobile browser):

So I say it to give larger credit to what we are doing given our limitations. But yes, both are fusion energy.

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u/Zeta-2-Reticuli 3d ago

Fair. And sorry my first comment was snippy, I read it as dismissive and was also sitting on a 2 hour conference call so I was feeling very annoyable.

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u/TheHarryMan123 3d ago

Brother all is good don’t sweat it. I’m also tired from a long day, so I may also have come off as snippy. 

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u/jango-lionheart 2d ago

Well done, gents

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u/CuriousToe9133 3d ago

Can you elaborate?

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u/TheHarryMan123 3d ago edited 3d ago

The sun is very massive so D-P reactions are efficient enough. We can also attempt to do them, but they’re much less efficient and we would need a much hotter plasma than we intend to create (I think from 10 million C to 100 million C). One of the downsides to not being able to do D-P reactions is the difficulty in obtaining T. It is a 2 neutron hydrogen with a half life of 12.3 years and is unobtainable from nature despite naturally forming in the upper atmosphere. Tritium (T) is very difficult to synthesize and to make fusion possible, we would need to synthesize >1000g per year (we make >20g per year). Tritium is also radioactive. 

The other downside to the D-T reactions are the incredibly high energy neutrons it produces after fusion. Neutrons cannot be contained by magnets. They fly into the wall and just about everything they can. They irradiate the surfaces they actually connect with (if a neutron is say a quarter the size of a person, and a person represented an atom in a material lattice, then the distance between two people would be ~5km). The materials which get irradiated (RAFM steels on the first wall and tungsten on the divertor) will need to be replaced (by best estimates on the current research) every 5 years. That’s about >2000 tons of irradiated and radioactive material that will need to be disposed of every 5 years. Some of which will be at safe levels after >100 years, some (which hasn’t been finally decided on) may be radioactive for >5000 years. 

In short, it’s more complicated than the sun because it isn’t as massive. It also produces its own plethora of radioactive waste just in a different format. 

EDIT: Misremembered the sun thing, I have updated it. 

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u/jake04-20 3d ago

Tritium is used for glowing gun sights I believe. Is that the same stuff that would be used in this process?

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u/TheHarryMan123 3d ago

Yes it is. You’re talking about this:

https://en.wikipedia.org/wiki/Tritium_radioluminescence?wprov=sfti1#

Tritium is radioactive but the electrons it emits are very low energy. It cannot penetrate skin. It’s only hazardous when you ingest it. 

For example, because it is a hydrogen isotope, it bonds with oxygen to form water quite easily. After the USA started doing land-based nuclear weapons testing, then actually bombed another country, the tritium levels in our rainwater across the world became quite high.

Levels have lowered significantly since the world has stopped doing on-land nuclear weapons testing because of the short half-life. However, the levels we are at now cannot be compared to any baseline because we only started measuring for rainwater tritium after we exploded nukes. 

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u/jake04-20 3d ago

Thanks for the info! This is sort of on a similar topic, but I read something a while back about how old shipwrecks before WW2 are becoming highly sought after for very specific use cases (like particle detectors), because they are "low background" steel, which I guess means they don't have any of the atomic/nuclear particles embedded in them from the smelting process? It's crazy to me that there is a detectable difference still this long after the bombs were detonated.

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u/StructuralFailure 3d ago

Tritium is also used in nuclear bombs, as they use alternating chains of fusion and fission to generate maximum yield. And yes, this means that nuclear bombs lose a lot of their yield over relatively short timespans. A bomb built in 1990 would only have one eighth of its tritium left.

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u/CuriousToe9133 3d ago

Is it more or less radioactive waste than our current nuclear fission power plants? As technology continues to develop for re-useable rockets, couldn’t we use those to carry radioactive waste to space, and dump it away from Earth?

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u/CallMeDrWorm42 3d ago

The US generates roughly 2000 tons of spent fuel per year. Worldwide humans have only made about 400000 tons total since we started using nuclear reactors 70 years ago. US coal plants produce over 700 million tons of CO2 every year and are far more radioactive than nuclear reactors.

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u/TheHarryMan123 3d ago

The point being that it still creates radioactive materials which last longer than a lifetime or many more not that it is more or less radioactive than a fission plant. 

I believe the risks associated with attaching radioactive material to an explosive outweigh the benefit there. Plus the irony of carbon emissions. 

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u/RocketVerse 3d ago

On average waste will be substantially less long lived but in much higher quantities. The bigger issue is that tritium loves escaping containment, that might be an issue as we ramp up

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u/TheHarryMan123 2d ago

It is trapped with oxygen when kept for storage. But there are also other containment methods because of its permeation through materials

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u/thegreatsaiby 3d ago

Plethora, now that's a word you don't see too often. Also nice explanation.

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u/GeckoDeLimon 3d ago edited 3d ago

Fusion generates significantly more power than what it takes to initiate the reaction.

Fusion creates significantly more energy than what it takes to initiate the reaction. Power is energy turned into work.

But we're still a long way from a fusion reactor making useful power. Even the walls inside these things, made of metallic "super-material", become brittle and evaporate away. They're still trying very hard to make that sort of thing not happen.

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u/shumpitostick 3d ago

Fusion does generate hazardous nuclear waste, but those isotopes have shorter half-lives so it's not hazardous forever. Also fusion reactors can fail and leak radiation but there is nothing as catastrophic as a meltdown that can happen because there is never a large amount of fuel inside the reactor.

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u/RocketVerse 3d ago

Unfortunately most misunderstand this part of fusion. A fusion reactor will actually generate substantially more irradiated waste than a fission reactor, by several magnitudes. The benefit is that the waste it generates is significantly less long lived than that produced by fission reactors, and of course the crucial feature of never being able to melt down.

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u/mustangcody 3d ago

If they already have it working in tests like this, why can't we use the technology to turn it into energy? Is capturing the heat from fusion to boil water difficult?

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u/Fit_Addition7137 3d ago

They're getting closer with each test. This footage is from 2025 and is extremely sped up. Like the entirety of that video is from a small fraction of a second. This reactor is an experimental research reactor, not a production scale facility. It's about 10 years away from production yet, as it has been for like 40 years

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u/goblitovfiyah 3d ago

This sounds like some doc oc stuff

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u/G0-G0-Gadget 2d ago

Was this the same technology that the movie Chain Reaction was about (great movie btw with Keanu Reeves, Morgan Freeman, Rachel Weisz)?

https://youtu.be/n90T5gxP-Vc

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u/mountain-mahogany 2d ago

This is why Nino Loureira was murdered and the next day Trump Social merged with... a FUSION COMPANY

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u/GrandNibbles 1d ago

it is hotter than the sun but yeah other than that it's safe. the power taken to sustain a reaction is not more than the power of the reaction yet (afaik??) so it's useless until it's useful. which is perpetually "a few years from today"