If the goal of fusion power research is to harness the power of the sun to produce power, shouldn't they be trying to replicate the conditions in the sun?
I'm not really too clear on fusion research, but it seems like they're trying to get self sustaining reactions by using low density plasma in a magnetic field.
Wouldn't it make more sense to try to replicate the conditions inside stars by using extremely dense hydrogen? Like pressurizing hydrogen to extreme levels and then heating it?
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>conditions in the sun
can't do, the pressure is too big to replicate
lack of pressure is offset with much higher temperatures than in the sun
Our current magnets are insufficient to recreate density and pressure akin to the centre of the sun. I don‘t know how you thought we could do that. It‘s the center of the fucking sun. I‘m also fairly sure that creating such a strong magnetic field would use up too much energy as well even if we could.
If we‘re disregarding magnetic confinement for sustained reactions, I guess you could look at wacky concepts like fusion engine. I wouldn‘t get my hopes up about that though.
We can already fuse hydrogen, we just can't do it on a small enough scale.
Is it even possible to hold hydrogen ions at high pressures using only a magnetic field?
The goal of thermonuclear power research is to harness the thermonuclear power.
>ions
>magnetic field
True.
While on sun, Deuterium Deuterium fusion runs at 15 million degrees of Celsius, in earth reactors temperature must be around 10 times that. So far, hottest continuous plasma was 80 million degrees. At this rate, fusion yet occurs, but is bellow critical mass, to provide continuous burning of plasma (this is the reason why all reactors so far consume more energy than they produce, since plasma must be constantly heated). Imagine carbon. We all know that once it gets burning, it emits large quantities of heat, but try to light it directly by simple match, and you will fail miserably.
Personally, Wendelstein x 7, not Iter, is way to go. I don't know much about pollywell reactors
?
...
So wouldn't the solution to the inability to reach critical mass with current techniques be to add more mass?
Exponentially more mass.
More than can feasibly be achieved with current technologies.
The better solution is improved technology, but this takes time and inspiration. Time is easy enough to come by, after all, fusion energy has been a 'in 20 years' technology for 50 years or so, inspiration, on the other hand, is more difficult.
Technically if you have enough of a budget you can hire enough scientists to brute force a solution. Issue is there's no gauge on how much money, or time, that involves, and there is no guarantee it will work.
True innovation just requires the right person to be in the the right place with the right resources at hand.
There's no guide on finding that person though, so things are probably just going to keep on going until that person shows up.
So when you say exponentially more mass, wouldn't a few gallons of liquid hydrogen be enough given that they're just using a few atoms at the moment?
we already know how to use fusion power. You push two atoms together very tightly until they ionically fuse and you get a star. Popsci baby-boomers figured they'd get free medical care with it so they keep throwing money at it.
>critical mass
the condition for fusion is not the same as fission. the equivalent criterion for ignition for a D-T reaction for example is to get the fusion triple product on the order of 10^21 KeV*s*m^-3.
this is the product of the plasma density, plasma pressure, and mean bulk plasma temperature
yes.
>the power of the Sun, in a rubber band
The forces involved are insane big, very hard to control.
ionise 1 mg of hydrogen, have the protons in one pile and the electrons in another pile 1 km(!) away - they still pull at each other with about 84 million N, comparable to the weight of the Eiffel tower.
youtube.com
Anyone interested in fusion should watch this video. Tokamak reactors are easily the best and most promising type of fusion generating device we have built and are likely to build for a long time. Stellarators may be good too but they're much more complex and would be difficult to mass produce, which is what we'd need to do in order to power the world with fusion.
Boiled down, the big breakthrough recently for fusion technology is the ability to construct new magnets out of a very high temperature superconducting material which previously couldn't be produced in pieces bigger than microscopic crystals. This new material will let us build much more powerful magnets using existing cooling technology, which in turn means much smaller magnets can hold higher density and higher temperature plasma. Essentially this means the minimum size of a net positive tokamak has dropped by a little more than an order of magnitude.
The old fusion technology pathway involved building ITER, a massive building-sized machine that would only be capable of sustaining conditions at the bottom of the range where self sustaining fusion power is possible. Instead, we can now build a reactor capable of the same level of sustained reaction as ITER which would fit into a normal sized room, and an actual fusion reactor producing gigawatts for the grid will only be a few times bigger.
Your triple product is nonsense. $P=P(\rho,T)$
Stronger magnets can't help you if the rest of your reactor gets ripped apart by the forces involved.
Seems like a meme, but i have yet to watch the video.
The high density approach is called Inertial Confinement Fusion.
You don't need high densities. The first thing you want to do is to overcome the mutual Coulomb barrier of two protons. The sun does that via Tunneling (c.f. the famous Gamov-peak). That's where the high densities come in, you need them for sufficient tunneling probabilities.
On Earth, because we can't recreate the densities, instead we overcome the Coulomb peak by brute-force heating.
Which is of course only true for the central part of the plasma. Due to the inefficiency of plasma to conduct heat, strong temperature gradients are generated, so that the plasma temperature reduces down to a comfy room temperature at the reactor walls.
How much fuel you inject into the reactor will control your number of reactions and is thus set by the demand in energy.
That's how we arrive at the low reactor densities. Simply not much material is needed if every reaction releases 20 MeV.
I'm intrigued by some of the smaller fusion efforts,General Fusion and Helion energy really pique my interest. GF has a big leg up in terms of practicality-their reactor has a lot of natural neutron shielding due to its in-built lead-lithium liquid vortex design for fuel breeding, so the actual metal it's made of has a lot less of an issue with helium erosion and neutron degredation. They have a way to go but it's a nifty idea to use shock waves to give a plasma the final push to fusion temperatures and pressures and they've made strides in heat and general TRL.
Helion arem ore mysterious but have some benefits in terms of direct energy conversion and using a less-nuetron intensive form of fusion, but i've heard much less out of them.
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sounds like a great idea! One more step towards becoming a Type 1 Civilization.
user....are you okay?
Case is, most great deal of electricity that current fusion reactors consume is trapped in cooling the super-magnets. Imagine, (according to one article) our current most advanced operating tokmak, JET, produces in pulse 25MW of heat energy, probably resulting in 16MW electric energy. Problem is, that for heating the plasam, cooling the magnets, which two presents mayor energy consumption in proccess, 700 MW of electricity is consumed.
If we managed to achive continious reaction, (which is advantage of stelator type reactor), it rid the need of further hating. Still, cooling the magnets of current generation to -270°C is extremely energy consuming, since you have to basically cool them with liquid helium. Now, if we manage to reduce temperature of superconducting magnets to higher temperatures, it would massively cut the energy expenditure of reactor. In turn, this would d lead us close to net energy surplus.
This is the challenge of today. If we manage this, we won huge victory for the world. Yet, this wont be easy, or at all, possible. But, we must try to figure out the answer.
Corection, magnets have to be cooled to -239, so liquid hydrogen
S-sorry, user. I went crazy there for a second.
Is cracking fusion primarily a monetary issue, or an engineering/theory issue?
As in, if Bill Gates wrote a blank check could we do it without much trouble?
we're already investing a lot of money in it
it's an engineering issue mostly. Gotta do some progresses in materials science before we get there.
Wendelstein 7-X will cost only a little over $1B across 20 years. The F-35 program is $1.5T over around 50 years.
Surely we could go further and achieve more with that kind of money?
Well ITER is 20B€
>tokamaks
>ExB drift
>good
you have absolutely no idea what you're talking about
Total brainlet when it comes to E&M here, but I have a question. What if we had a long, straight tube with a solenoid wrapped around it to provide a longitudinal magnetic field like in a tokomak, and additionally had foil rings outside as well with a voltage between each one such that the central foils are negatively charged and the end foils are positively charged. The plasma would also have to be positive. This potential difference from center to end would do work on the particles, reducing their collective pressure and/or temperature to levels at the ends that the container can withstand physical contact, while maintaining fusion conditions in the center. One end can have a slightly easier to escape well, such that there is a net flow through the device and the gas escaping the easy end is at a high temperature that can be used to heat water. Fuel can be jetted into the harder to escape end. Would this work?
Did not mean to say additionally and as well in the same sentence.
do the math, then tell us
It is also critically underfunded since ever
C'thulu fthagn
The half life of a hydrogen atom in the sun is about 4 billion years. The power production of the sun is about 276.5 watts/m3. The pressure is 3.84 trillion psi. For comparison humans at rest generate 1408.5 watts/m3.
Turns out its a hell of a lot easier to make small scale (something we can build on earth) fusion by increasing the temperature rather than the pressure.
Wrong, they are building a massive fucking fusion reactor in Europe. It sucked up pretty much all the worlds fusion reactor building budget. It was designed on old superconductor tech, the new shit is like 4x better and due to scaling could have cut the cost by about 30x, but they will keep building this massive piece of shit into the foreseeable future because too many jobs rely on it.
And on top of that we are pretty sure stellarators work quite a bit better than tokamaks.
>Wouldn't it make more sense to try to replicate the conditions inside stars by using extremely dense hydrogen? Like pressurizing hydrogen to extreme levels and then heating it?
That’s exactly what tokamak reactors (the one in your pic) do. Its called magnetic confinement fusion, which involves use of magnetic fields, centrifugal force, high temperature, and pressure to try to simulate the conditions in stars like the sun. Its the closest analog to a star we can build without learning how to manipulate gravity first.
>Personally, Wendelstein x 7, not Iter, is way to go.
Optimized stellerators are looking pretty sexy right now. But I can't help but shake the feeling that they'll just be too complicated and therefore too expensive for wide-scale use.
ITER will still get results eventually. Cancelling it at this stage wouldn't really help anyone anymore. Although I'll admit it would be both hilarious and sad if a project like Tokamak Energy's for example would get results quicker with a fraction of the cost and time by the mid 20s
>Is cracking fusion primarily a monetary issue, or an engineering/theory issue?
Money and construction time issues. Theory is not the issue. Theory is doing fine.
The problem is that everytime we have a cool design it takes fucking 20 years or so for it to get fucking built.
Wendelstein 7X is a project from the late 80s.
Same with ITER.
Sure, some recent advancements in super conductors, especially the really cool high-temperature stuff may have been found independent of reactor experiments, but still, we probably could've had fusion much sooner. With a more concentrated and more well-funded approach.
ITER is especially infuriating in that regard, because the way they divide work between partner countries is basically set-up as inefficiently as possible. Sure, there was some idea about every country getting the knowledge about fusion reactor tech by building a bit of every component themselves, but with how much that has delayed everything and by how much that amplified the costs, it's pretty much impossible to justify.
That fusion development took so long is especially infuriating considering the timescale of climate change right now. With the 2 degree goal basically demanding a total stop of carbon emissions by 2050 or so, at the current timescale, fusion is basically set to arrive exactly by the time that shit should've already been sorted out through renewables.
>Theory is not the issue. Theory is doing fine.
The part I don't understand about this is, if it is all "figured out" theoretically, why do people keep building reactors that don't sustain a chain reaction? Shouldn't they know ahead of time if it's going to work or not if the theory is sound?
probably because that's just the ramblings of some guy on an anonymous Taiwanese dairy cow image forum who has no knowledge of plasma physics
I didn't say theory was done. I said they were doing fine.
There are still a lot of smaller things to work out and all manor of engineering issues and possible optimizations. A reactor doesn't need to be to-scale to figure a lot of that stuff out.
Also the basics are figured out. ITER won't go live and suddenly produce twice as much or half as little as they expected unless they completely fucked up somewhere during construction.
Hydrogen would freeze. It also embrittles metals, which is why it's difficult to use as rocket fuel.
Helium not only has a lower boiling point, it also has no freezing point at standard pressure, so you can cool it until it becomes a super-fluid if you want to. Helium is the only liquid that can exist at temperatures cold enough for use inside modern superconducting magnets while also being feasible to use from a materials standpoint.
I say modern superconducting magnets but really I mean everything except a very new material that just recently we have been able to produce in batches large enough to be useful for building magnets, and is superconducting at temperatures high enough that we can use liquid nitrogen instead of liquid helium. Nitrogen is non reactive in the environment of the coolant loop and doesn't cause embrittlement, plus it's far cheaper and there is no shortage unlike helium. If we want to build thousands of fusion power plants in the future, we can't use helium as a coolant, because we simply don't have enough. The ability to use much higher temperature cryogenic liquids would massively improve the feasibility of a fusion-only large scale power grid.
I'm actually not a huge advocate for fusion power by the way, I'm in the fission camp. Breeder reactors use fuels that are much more common than fusion fuels, unless we can get H-H fusion feasible, which doesn't seem to be possible. Breeder reactors are also orders of magnitude easier in pretty much every way, and if you're smart about fuel reprocessing they don't produce any long term radioactive waste. There are thorium reactor designs that wouldn't make trans-uranics, and would burn up 99% of the fuel load, with the remaining 1% being bred into the plutonium isotope that NASA uses to build RTGs. It's also possible to make fission reactors small and light enough to power spacecraft, whereas fusion has no hope of achieving this.
> but still, we probably could've had fusion much sooner.
how? Without modern tech it is physically impossible to build a practical fusion plant. One that is robust and actually produces power
>global warming rant
oh i see, you people
W7-X is a neat plasma stability experiment, but it's farther from sustaining a power positive fusion reaction than the tokamak design.
The problem with fusion that people are trying to solve isn't plasma instability, although that is an issue. The problem is achieving enough fusion reactions per second that the plasma temperature remains high of its own accord. All current fusion reactors are too small to achieve this Q factor, and their magnets are not powerful enough. To achieve a high Q factor you either need a very big fusion chamber, working with the square-cube law, or you need to go much hotter, which requires a more powerful magnetic field. With current magnet technology we need a reactor the size of ITER (840 cubic meters of plasma volume) to achieve the minimum Q factor to keep the reactor running of its own accord. With better magnets, using higher temperature superconductors for example, the maximum confine-able plasma temperature goes up, and the minimum size required for a Q factor of 1 goes down in proportion.
Stellarators could become dominant over tokamaks in the future, but they're so much more complex and difficult to build that it's unlikely that they'd ever out-compete tokamaks even if the latter never achieves robust plasma confinement. I any case, stellarators using modern magnet technology would still need to be much bigger than the W7-X for net-positive fusion power to be achievable.
We know how to get fusion to work, what these experiments explore is how to deal with the conditions present inside the reactor, like extreme neutron flux and plasma instability.
The W7-X exists specifically to explore better ways of confining plasma. ITER should generate power, but it's meant more specifically to explore means of shielding the reactor walls from neutrons and methods of breeding tritium from those neutrons. Since deuterium-tritium fusion is the only really feasible fusion fuel mixture at this point, and tritium is extremely rare, we'll need to be able to produce the tritium we need from the relatively common deuterium we can pull out of the oceans if fusion power is ever going to become a significant contributor to the grid.
Solving these problems should be feasible according to theory, but working out the reality of the engineering is the challenge. Don't want to build a massive ten meter fusion power reactor for energy production just to figure out it can't breed fuel effectively enough or too much erosion of the walls is contaminating the plasma and stopping the fusion reaction.
Real fusion power begins when multiple fusion reactors are fused together...
that has already been researched in the 70's. What you're describing is a capped magnetic bottle. Ppl have burned whole careers on this.
Doesn't work.
Hah, the thorium meme.
U got any video explaining recent research?
>fusion power research is to harness the power of the sun to produce power
You're thinking of solar power
Any fusion proponents care to explain what material could possibly be used to overcome the neutron irradiation and subsequent degradation?
>Woops I accidentally confinement failure
I-Fields that naturally occur as a result of the M-particles produced by the Minovsky-Ionesco fusion reaction.
Just like in real life.
FLiBe. Watch the video user linked above.
It can do everything. Absorb slow neutrons (you still need additional shielding for fast ones), take out the heat by absorbing the slow neutrons, and breed tritium in the process.
The technology has been there for decades brainlet.
>doesn't explain
>just spouts memes
Its retarded in a way that its still just going to generate heat and spin the turbines. The next generation energy generation should involve direct electron transfer
>thorium
Poo in loos are sitting on most of the exploitable reserves. If you're not a britbong, good luck securing that resource.
youtube.com
Suck on a solar-powered dick, you piece of shit.
It was a joke dude calm down.
A lot of the support for solar and wind come from the zero-growth, Malthusian sociopaths because they know this shit will never provide enough power for a developed, first world nation and it will force the Western nations to lower their standard of living and even population.
No love for Polywell fusion?
If you can get it work, sure.
Solar is seeing exponential increases in output per cost, eventually it will be the only rational choice, obviously that day is not here yet
Crystals, there is solid grid and material in it that carries, you stimulate carry so much it hit eachother.
Lawson criteria for fusion is temperature x density x confinement time.
So far, we can't achieve all 3 simultaneously.
Can't hold high pressure long in a magnetic field.
Another factor, rarely mentioned, is that dense objects (denser than a fair vacuum) radiate heat as the 4th power of absolute temperature. At fusion temperatures, plasma would lose heat much too fast to "ignite". (Also melt the reactor, but that's a secondary issue.) 4th order rule doesn't apply to very thin plasmas.
"Duplicating the Sun" is a misnomer. Reactions proceed _very_ slowly at sun-core conditions. YOU generate more energy per pound of your mass.
We have to use faster reactions (deuterium and tritium) and much higher temperatures to get useful power.
The primary problem is that it takes too much power to run the electromagnets right?
Couldn't they just run it off another generator until the reactor produces enough power to run the magnets on its own?
the radiating of energy from the plasma is less about typical "radiation" heat loss, and more a problem of the loss of energy from electrons processing about the magnetic field line (with larmor radii much smaller than the ions)
plasma microinstabilities and heating are significant challenges
>heating is a significant challenge
Nigga just turn the microwave up to 11.