"the only commercial entity to achieve fusion so far"
...is this true? It's pretty trivial to achieve fusion (laughabe efficiency, but still fusion!) with a few thousand dollars and a well-funded garage. Maybe "commercial entity whose goal is to generate positive-yield fusion" is what they mean..
> Maybe "commercial entity whose goal is to generate positive-yield fusion" is what they mean..
Maybe, but that wouldn't be true either. Zap Energy has demonstrated neutron production in D-D reactions. I think Helion has, too (and possibly in D-T reactions as well?). Neither is particularly close to break-even, but then, neither are these people. It's a baffling claim.
C. L. Stong's "The Amateur Scientist" column in Scientific American described building a Van de Graaf accelerator capable of inducing fusion at a cost of $200 (in 1959). https://www.jstor.org/stable/24944895
I think that the title is a bit click-baity as the Q ratio reported for the experiment is still 0.00005 (0.005 percent quoting the article).
Still an impressive achievement, but would've not used the word "groundbreaking" IMHO. I believe that in the context of nuclear fusion that word is often used to allude at reaching an energy surplus out of the reaction.
> "HB11 Energy’s research demonstrated that its hydrogen-boron energy technology is now four orders of magnitude away from achieving net energy gain when catalyzed by a laser," reads the press release. "This is many orders of magnitude higher than those reported by any other fusion company, most of which have not generated any reaction despite billions of dollars invested in the field.
> HB11 claims is a "world-first 'material' number of fusion reactions by a private company
So they have a result which is 10x better than they thought will be, but still way lower than stellarator etc.
And still lower than other laser systems using inertial confinement. If I'm reading NIF's recent paper right, they're claiming Q_a of above ~1.4, or Q = ~0.28
Edit: Wikipedia suggests that they were using a different method to calculate Q, only measuring the power input to plasma vs output from fusion, not including system losses. So that figure is probably not directly comparable.
> the NIF used ~477 MJ of electrical energy to get ~1.8 MJ of energy into the target to create ~1.3 MJ of fusion energy
The spin is also a bit weird... suggesting that their experimental results were ten times better than their theory predicted doesn't exactly lend a ton of confidence to me in their theory.
It's interesting, at that scale. But just imagine if someone designing a power plant said that their reactor generated 10x the power calculated.
That depends on what you mean by "close" and "viable", imo. We know that tokamaks will work if we build them big enough. So it's essentially a matter of dumping sufficient billions into large construction projects, i.e. ITER and DEMO. There are of course some open engineering questions, but afaik, they mostly concern economic viability, e.g. durability of materials involved.
Big enough, or high-enough field strength. For a given power density, I think required radius scales inversely with the fourth power of the field strength, or something along those lines. ITER was designed when niobium-tin superconductors where the best available, which will limit their field strength to around 13T, but newer HTS magnets should allow some of the upstarts to achieve comparable power densities with much smaller reactors, which should help with at least the economic concerns (durability is still a big concern, though).
CFS has an interesting design for that, too. MIT demonstrated joints in REBCO tape that don't introduce significant resistance. By putting these joints in the coils, CFS has a design that will let them open up the reactor and replace the inner wall annually. The inner wall will be 3D-printed, and immersed in a pool of molten salt that functions as coolant and breeding blanket.
We definitely don't "know" that yet. There is for example no experiment that has ever actually tried to extract any energy from the fusion reaction - it's assumed that the lithium blanket idea will work, but this remains more or less purely theoretical. It's sound science, but we're nowhere near sound engineering there.
This video gets posted lately every time anyone posts any fusion news lately. It's not a bad video, but I think the point everyone is trying to make is like, "we're not even close, we're orders of magnitude away!", and that's true, but I think maybe a bit misleading. Since fusion experiments began in earnest in the mid-20th century, we've improved in terms of Q by about four orders of magnitude, and the pace of improvement was pretty steady through about the mid-90s, when ITER started to suck all the air (funding) out of the room. Commercial viability is probably somewhere between Q=10 and Q=30, depending who you ask and what specific technology you're talking about, and the best we've done so far is around Q=0.7. So... four orders of magnitude so far, and between one and two still to go. And finally ITER has some competition that could get progress back on track. It's a big lift, but not, like, impossibly or unattainably large.
Q=10, for the Q in typical use, would have no chance of commercial viability. More precisely, it would have substantially less commercial viability than fission, which today lacks it. If we got to Q=1000, we would have viability that might match fission. Viability better than fission is not possible with hot-neutron fusion.
Thus, hot-neutron fusion is a dead end. It might be that things learned chasing hot-neutron fusion will turn out to be useful for something else, such as aneutronic fusion. But work on aneutronic fusion, itself, would be overwhelmingly more useful. Very little work is being done on aneutronic fusion.
....but if I'm understanding the article, and comments here from others more knowledgeable than me, this development is, in fact, work being done on aneutronic fusion.
Qplasma = infinity just means that you have transferred the burden from just getting your plasma fusing reliably to the problem of converting the energy coming out into useful form. That second burden is one nobody has even started on. All indications are that it cannot match the economic value, even, of fission, at any Q.
260 GW electrical power is being generated from fission neutrons right now.
The fact that a fusion test reactor hasn't done this yet is a flimsy point. A burning plasma test machine hasn't even been made. How would you propose blankets and shields be demonstrated if not in a burning plasma machine?
> 260 GW electrical power is being generated from fission neutrons right now.
At enormous cost. Nobody even has a plan for a way to operate a fusion plant at anything close to matching fission's cost, and fission itself gets less economically competitive with each passing day.
If a fusion plant could be operated competitively, surely running the same energy collection system wrapped around a fission pile would do just as well, and thus better than existing fission plants? Try it and see!
This notion of cost is misguided. Fossil fuels are not charged for their externalities. Mankind collectively pays for it decades later.
And what of renewables? We couldn't run our society on wind and solar while still feeding everyone with the land we have without displacing millions. Even if we did, the total effort (cost) to society to build and replace terra scale machine arrays would be incredible.
Fission offers a much more dense path. But what of the proliferation and accident concerns? If you set aside quarterly profits just for a moment you might see a path for humanity to stay on its current industrial path if it takes its medicine and solves its energy crisis.
As has been explained to you numerous times in this space, the amount of land needed for enough solar panels for all our energy needs is less than the space currently devoted to fossil fuel extraction.
Furthermore, there is never any need to devote space exclusively to solar panels. They coexist well with buildings, where their shade extends the life of roofing material, with parking lots, where they protect cars from damaging sun, with canals and reservoirs, where they reduce evaporation, and with pasture and crop land, where they increase yield by reducing heat stress, and cut irrigation demand by reducing evaporation.
I hope you will choose in the future not to propagate falsehoods you have already been corrected on.
It has also been explained that energy from renewables is radically cheaper than from nukes. So, if building out solar were too expensive, building the nukes for the same output would be overwhelmingly moreso. But in fact cost for renewables and for storage is still in free-fall, so nukes of any sort get less competitive every day.
Fission lacks commercial viability in large measure due to extreme, overly burdensome regulatory regimes that require dramatic overbuilding for safety margins, high barriers to adopting potentially-cheaper but architecturally novel designs (basically anything other than pressurized water reactors), and years and years of capital-cost-incurring red tape to deal with compliance.
I think on paper, you're right that fission ought to be more commercially viable than anything any of the fusion people will be able to achieve any time soon, but I think there's at least a chance that fusion technologies will manage to get themselves regulated in a way that makes the all-in costs of fusion projects much more manageable, even if the reactor itself is more expensive, less power-dense, etc. In an NRC roundtable discussion last week, there was discussion suggesting that much of the need for, say, handling tritium, could be regulated under existing, relatively lightweight regulatory structures already in place for things like nuclear medicine waste, and it seems like both the US and UK energy regulatory authorities are pretty interested in building streamlined regulatory structures that make fusion much more approachable than fission historically has been.
Nukes lack commercial viability because they lack commercial viability.
Much of their cost overburden arises from corruption tax, a problem common to public works projects massively expensive enough to need buy-in from a wide range of stakeholders who then expect patronage, to be charged to extreme cost overruns and schedule slip.
Since no nuke plant has ever been built with private money, and there is no realistic prospect of one ever being built with only private money, this overburden will be lifted only when corruption has been suppressed. Then we will still have the enormous, foreseeable decommissioning cost, the very high operating cost, and the astronomical liability subsidy always omitted from cost figures, but charged to the general public.
> Q=10, for the Q in typical use, would have no chance of commercial viability.
This statement is not necessarily universally true. In particular, if one can convert the fusion energy to electricity with high efficiency (i.e., not by an ordinary thermal cycle as would be needed for the neutron energy in a DT fusion reactor), and if one could also recover the input energy to the plasma with high efficiency, then it could be practical to have a much lower Q.
Helion's scheme is like this. I understand they've demonstrated 95% recovery of plasma energy (no fusion occurring, just heating and compressing the plasma, then recovering that energy to capacitors), which is rather impressive. Their commercial 50 MW concept would have Q = 2.
Helion is the fusion company I feel most positive about, for that and other interrelated reasons.
She conflates ICF and MCF. There are numerous reasons to be pessimistic about ICF.
MCF is quite close to triple product performance of a burning plasma, where self-heating becomes dominant. There is a financial hurdle going from a research device to a nuclear machine capable of burning plasma. People are doing it right now though.
That video makes it sound like we're far away, because we need tokamak output to be about a hundred times better than we've achieved.
What it ignores is that tokamak output is highly nonlinear. It scales with the square of plasma volume, and the fourth power of magnetic field strength. Double the field, 16X the output. These scaling laws are very well established at this point.
The plasma volume scaling is why ITER is so big. But after ITER was designed, people invented REBCO superconducting tape, which can support much stronger magnetic fields and is commercially available.
Using those fields, CFS is building their SPARC reactor, which will get ITER-level output (Qplasma=10) from a reactor half the size of JET, which was built in four years. (Three years for the building, one year for the reactor inside.) If that goes well, the next step would be build their ARC reactor, which will be the same size as JET and get commercial-level output.
(Some of the alternate designs also have great scaling in theory, but we don't understand their plasma physics as well so it's harder to predict how they'll turn out.)
Perhaps, but in that case I would have phrased with something similar to: "New approach to Nuclear Fusion using PW lasers shows promise". Sorry, my new year resolution is to try to pay more attention to this kind of click-bait. Once you start paying attention you see that 1) it is actually everywhere, 2) that since you now notice it is really annoying like being in a room where everyone is screaming, and 3) you can't unsee it :( .
>HB11 Energy’s research demonstrated that its hydrogen-boron energy technology is now four orders of magnitude away from achieving net energy gain when catalyzed by a laser
the accelerator based fusion - like accelerating protons into a solid target - is probably among the easiest ways to get some fusion. Improving it is though a completely different thing - as even the solid targets are really mostly space between the atoms (and thus the overwhelming majority of the incoming protons lose the energy by heating the target instead of hitting the target's atoms), the density of the target to achieve break even should be on the scale of like 10x density of lead. The only known ways to get such matter densities is by compressing the matter by something like X-rays of the power comparable to that of the nuke explosion generated X-rays (like for example is done in Sandia Z-machine or NIF lasers).
> Its first demo has produced 10 times more fusion reactions than expected
I'm not a physicist or a professional scientist in any way. But is this at all normal? 10 times means a whole order of magnitude. Is that a sign that the math is wrong somewhere or that some measurement is wrong somewhere?
For those who are not aware why this might be important, the hydrogen-boron fusion reaction is the easiest among the so-called aneutronic fusion reactions, i.e. among the fusion reactions whose products are all stable nuclei.
This kind of fusion is the only kind of fusion that may be considered clean, because the risks of producing radioactive waste are negligible.
The easier kinds of fusion, which are attempted by almost all fusion research projects, e.g. the deuterium-tritium fusion, produce most of the energy in the form of high-speed neutrons, which must be absorbed by some shield. The shield will soon become radioactive, generating a lot of radioactive waste, even if it may be hoped that by choosing carefully the shield material the kind of radioactive waste that is produced may be less dangerous than the waste generated by fission reactors.
So any research results about hydrogen-boron fusion are far more important than the results about easier fusion reactions.
Unfortunately, even with these positive news, there is no clear path towards developing some kind of fusion reactor that could use this better fusion reaction.
>So any research results about hydrogen-boron fusion are far more important than the results about easier fusion reactions.
That's like saying research results in exhaust filters was much more important than research into combustion engines back when we had none - how does that make any sense ? Disposing radioactive waste isn't impossible, it's just not trivial, if that was the only downside of fission plants I doubt many people would have a problem with them. Pollution produced by coal plants is categorically worse and yet we have those all over the place.
It is not just the problem of disposing the waste.
Any neutron shield will be destroyed in a relatively short time, so it will have to be replaced and processed for the separation of the radioactive waste.
This is certain to greatly increase the cost of operation for a fusion reactor.
Also the fusion energy carried by the neutrons will be recovered only partially, because it will be transformed in heat in the shield and taken away by a coolant and then the heat will be used in electric generators, like the heat produced by fission or by fossil fuel burning.
Because the products of an aneutronic fusion reaction are high-speed charged particles, it is theoretically possible to make a direct electric generator, without using heat as an intermediate, which could have a much higher efficiency.
Making a small fusion reactor that produces neutrons would be always impossible if living beings are close, due to the need for a neutron shield. So you will never have e.g. a car with such a fusion reactor. There are no known size limits for a fusion reactor with hydrogen-boron, so it might be possible to make reactors small enough to power a house or a vehicle.
So if it would be possible to control a fusion reaction like hydrogen-boron, it would be possible to make fusion reactors that could produce much cheaper energy than it is possible with the easier fusion reactions, for which it remains to be proven if they could become economically viable, even long after the technical problems needed to enable the production of more energy than consumed will be solved.
However, many real breaktroughs would be needed to discover how to do aneutronic fusion reactions, at the scale needed for energy production.
The easier fusion reactions, like deuterium-tritium or deuterium-deuterium, have so many intrinsic disadvantages and so little advantages over fission reactors that it does not seem likely that they could ever become the main method for energy production.
Billion degree partials produce very high energy photons. Thus it’s still producing ionizing radiation so scaling down to a car sized reactor isn’t going to practical.
Further, Hydrogen born is also only aneutronic if the chamber is kept free from everything else to an impractical standard. So, yes in theory you don’t need neutron shielding, but in practice you very much need shielding at useful sustained power outputs. In the end you will still produce radioactive waste, just less of it.
There are negligible chances that a fusion reaction like hydrogen-boron will ever be achieved by thermal means.
If such fusion reactions will ever be used, some means to accelerate the nuclei will have to be used, so that they will have a directed movement not a random thermal movement.
So there will be no billion degree plasma in thermal equilibrium, radiating gamma-ray photons.
Some high-energy photons will be produced in secondary reactions, but that cannot be compared to standard fusion, where producing neutrons is the intended result of the reactions.
It cannot be predicted yet how much shielding might be needed, but in any case that would not be comparable with the needs of standard fusion.
The real problem of the hydrogen-boron fusion is that, for now, there is no known method that could ensure a high-enough probability of collisions between accelerated nuclei and a solid target or other accelerated nuclei, so that the rate of collisions would be high enough to generate more energy than consumed.
HB11 Energy's method is non-thermal. They use a petawatt picosecond laser, which is so intense that it shoves the target nuclei sideways into the nuclei behind them.
> Disposing radioactive waste isn't impossible, it's just not trivial
Source? To my knowledge, all radioactive waste disposal systems we have tried to this day have profoundly failed... and some even have failed years before they were scheduled to store any nuclear waste (eg. deadly gallery collapse in Bure, France).
Most radioactive waste disposal schemes I've heard of have been shelved because of NIMBYism. But it hasn't even been an issue, because most radioactive waste is so benign that just leaving it in storage containers on-site is fine anyway.
There are today 0 long term waste facilities in the world, so none have failed obviously. There are a lot of (non-military) medium term waste facilities (since that is all we need right now) and none of them have experienced any radiation leak.
That's indeed the case, but it also avoids the neutron embrittlement of the reactor building, it avoids a lot of the costly maintenances associated with it (replace strut X every 1.5 years of operation), and said maintenances would also have been complicated by having to operate in a building which is now itself radioactive due to neutron activation.
The beauty of pB11 is that it just produces (mostly) helium, so it doesn't make the place radioactive. A very small amount of reactions result in short lived C11 (20 minutes half life) and the occasional neutron, but nowhere near the amount of DT (1 neutron per reaction).
No proliferation potential, no waste disposal problem, no dangerous fuel also lead to greatly reduced security costs. And very little decommissioning costs.
It will still produce neutrons via the (alpha,n) reaction on 11B. And it will produce very energetic gammas by the (p,gamma) reaction. These gammas are energetic enough to cause photonuclear reactions in the surrounding materials, including production of photoneutrons.
While the amount of neutrons would be so low that materials could handle them, they'd still make the reactor hot enough that hands-on maintenance would not be possible (it would make it easier on remotely operated repair machines, though.)
It's a shame none of the p-11B schemes appear to be workable. Helion's approach seems more realistic (if still a stretch) and would also greatly ease neutron levels, if not to the same extent p-11B would.
I was under the impression that the neutron flux would be very low, and those neutrons would not be likely to activate any material due to their energy - I stand corrected, thank you.
Yes, the neutron flux would be very low. But it doesn't take much activation to exceed the limit for hands-on maintenance of the innermost part of the reactor.
Another advantage of hydrogen-boron fusion is that all the reaction products are charged. Therefore (theoretically) it would be possible to use *very* efficient magnetohydrodynamic methods of converting the reaction energy to electric energy.
More mainstream fusion methods have to go through the typical hot water -> steam -> steam turbine route. There is a theoretical limit to the efficiency of this conversion (around 40%). In addition, the cost of electricity has a lower limit based on the capital expense of the steam turbine/generator. H-B11 fusion could be order of magnitudes cheaper.
So if I understand this correctly this essentially creates an electric charge from initially uncharged particles. Wouldn't running a fusion like this lead to us accumulating more and more of a one-sided charge over time?
I guess it doesn't matter so much on Earth, but for instance if you ran a fusion reactor like that on a space station. Wouldn't it become electrically charged?
No, there are still plenty of electrons. You start with hydrogen (one proton, one electron) and boron (five protons, five electrons). You end with three heliums (each with two proton, two electrons).
The energy isn't extracted because of a build-up of charge. What happens is that each nuclear reaction is a tiny explosion. The helium nuclei shoot out really fast, and they're positively charged. You just need them to push through a magnetic field, and then you're getting electricity, like any generator moving magnets through a coil.
That is not HB11's proposed direct conversion scheme. HB11 proposes to have the alpha particles go up a large potential gradient, in effect charging a capacitor.
I don't think their scheme works, btw.
Having the ions move against a magnetic field doesn't change their energy. What would be needed for that scheme is to subject the ions to a changing magnetic field to produce an electric field that reduces their energy. Helion proposes something like this.
Ok fine, that's a separate issue, maybe you're right.
But also maybe there's a chance that there's a way to make it work (as your link suggests at the end). It seems to me that the initial impetus, a small explosion of charged particles, is the same for both HB11 and Helion. So it doesn't seem like it matters if HB11's energy extraction doesn't work, as long as Helion's does.
I feel like worrying about the cost/efficiency of the heat engine of a fusion device at this stage is putting the cart before the horse. 40% efficiency is really good when the reactants are practically free.
IMO the reason that HB11 may actually succeed is that the reaction keeps most of the output energy in charged particles in the plasma, so it's more feasible to achieve true ignition than when neutrons carry most of the output energy away from the plasma.
I have already mentioned the problem in another reply above.
People try mostly the fusion between hydrogen isotopes, or at most between hydrogen and lithium, because these nuclei have a low electric charge, 1 for hydrogen and 3 for lithium, so that the repulsion forces between them are relatively small.
When nuclei with greater electric charge are involved, e.g. boron, the repulsion forces increase. To overcome them, the nuclei must have a higher relative velocity before collision.
There are 2 ways to obtain high-speed nuclei, either by heating some plasma until the nuclei have a random thermal motion with high-enough typical velocities, or instead of heating everything and hoping for random collisions, you accelerate somehow some nuclei towards others, so that their movement is directed, not random.
It is already very difficult to contain plasma hot enough for deuterium fusion. There are very small chances for being able to contain and control the much hotter plasma that would be needed for fusion reactions with heavier nuclei.
So attempting to do hydrogen-boron fusion with the methods tried for deuterium-tritium seems doomed to fail.
The workaround is to abandon the thermal way and to search for a way to cause the fusion of accelerated nuclei, using some combination of electric fields, magnetic fields and lasers.
To produce more energy than consumed, it is required to have a very high probability that the accelerated nuclei will collide with their target (which might be fixed or also accelerated). For this either the ion beams would have to be very dense, or their positions would have to be controlled with nanometer precision or a single primary collision should cause multiple secondary collisions, or some other means would have to be discovered to ensure that the accelerated ions collide with the target instead of missing it.
All of the methods that have been imagined yet have a collision probability lower than needed by a few orders of magnitude.
So several real breakthroughs would be needed to be able to produce energy in this way.
The only hope for this is based on the fact that are no known reasons that would make this target impossible, while for the deuterium based fusion reactions there are a few serious disadvantages that are impossible to overcome, mainly caused by the facts that the energy is produced as neutrons and that deuterium and tritium have low availability.
Helion's DD (+ D3He) approach produces much fewer (and lower energy) neutrons than DT reactors, to the extent that the first wall could become a lifetime component of the reactor.
If you want extremely low neutron production, Princeton Satellite Systems has a scheme using a field reversed configuration (like Helion) but driven by an "odd parity" rotating magnetic field. This scheme causes 3He ions to have high energy, but the D ions to not, so DD fusion is suppressed. Neutron output is claimed to be just 0.1% of the fusion output, similar to p-11B. But you'd need a source of 3He. I have a question about recovery of energy from scattered 3He ions that didn't fuse in this scheme.
Yes, as you say, the main problem with this is that 3-helium has a much lower availability than even tritium, which has to be produced from deuterium, consuming a part of the energy output of a deuterium-tritium fusion reactor.
It seems that there is some 3-helium stored in the core of the Earth, but only a small part of it trickles continuously to the surface. When it reaches the atmosphere without being captured, it is lost quickly to the outer space.
Because of that, 3-helium is very expensive, but more importantly, the quantity that could be extracted each year is limited.
Even if the entire flow of 3-helium from the core could be captured, the energy that could be produced would be much less than what can be produced from uranium, not even counting the much larger reserves of thorium.
There have been some speculations that there might be larger reserves of 3-helium on the Moon, so that the only possible use of deuteron-helion fusion reactors in a not too distant future might be in some Moon stations.
3He is very sparse in the lunar regolith, maybe 10 ppb. So that's not a long term source, and extracting it would be very difficult.
I have hoped there's a "Planet X" in the outer solar system that's sufficiently small to easily land on and return to space, but large enough that it could retain some primordial helium in its atmosphere. If so, it might be the best place in the solar system to obtain the isotope, assuming a D3He fusion rocket could get out there and back quickly enough.
We know very little yet about the precise chemical composition of the many large bodies from the Kuiper belt.
So, at least until we will know more, there is still a chance for your hope to be fulfilled.
It is plausible to expect a larger 3-helium content there, but it cannot be estimated yet whether it would be so abundant that it would be worthwhile to extract and bring back.
It might be useful in situ. I.e., maybe you don't need to bring it back.
In the distant future, most civilization will be in and beyond the Kuiper belt, because while energy is as cheap as a supply of 2H and 3He (and eventually H and 11B), cold is hard to get in substantial quantity except far enough from a star. We will need a lot of cold.
If intelligent life developed D + D fusion it could live independently of stars since a high fraction of the mass of outer solar system, cometary, and interstellar objects is water, water which is a bit more D-rich than terrestrial water.
D + D fusion isn't that much harder than D + T fusion and it's imaginable that a scaled up version of a D + T reactor would work for D + D. (By "scaled up" imagine a large space colony with a closed ecosystem which uses D + D energy to replace sunlight.)
D + D fusion produces copious amounts of T and He3. These isotopes would burn up quickly in such a reactor but certainly some could be extracted. The He3 can be captured and used directly for fuel. The T decays with a 12 year half life. It could either be fed into D + T reactors or allowed to decay to produce more He 3.
The best use for D + He3 imagined yet is something like
which might be realizable with heavy ion ignition but the ignition system would be physically large which would scale the whole spacecraft up to "manned interstellar colonizer" as opposed to "very long range Voyager."
Now a D + D culture would already be "interstellar" in that it could support large populations in the spaces between the stars. A civilization like that would be able to cross from one star to another in 10,000 years or so but they might not care at all because they can live their lifestyle just fine without stars. Thus they might not be that motivated to develop in-a-human-lifetime interstellar travel.
Note a D + T fusion economy also could produce large amounts of He3 if that was wanted because a D + T economy is going to breed large amounts of T from lithium. If some of that is allowed to decay you get He3 which can be diverted to whatever use people have for it.
Adding up those options I think the trace quantities of He3 that might turn up away from Earth don't move the needle.
3He has almost exactly the availability of tritium, around here, because (almost) every last atom of tritium you manufacture will, in pretty short order, become 3He, unless you go fusing it first.
It seems likely that the atmosphere of Neptune has a useful fraction of 3He. But you need to get there first, with apparatus to collect it. For that, you probably need a fusion rocket, and 3He to burn in it.
3He can be produced, as you say, by storing the tritium and waiting for it to decay.
Making the tritium requires another fusion or fission reactor, in which case there is no point in trying to develop a 3He fusion reactor, because it will be advantageous only if it can replace the fission reactors and the "dirty" fusion reactors.
If those are still needed to produce the nuclear fuel, nothing is gained by using 3He.
If there would have existed a natural source of sufficient 3He, then things would have been very different and the deuterium-3He fusion would have been the top priority in fusion research.
A much more likely use of 3He is inside the so-called tritium-suppressed deuterium-deuterium fusion reactors.
The deuterium-deuterium reactions produce both tritium and 3He. If the tritium is removed continuously from the fusion reactor, then it is stored for a long enough time until it decays into 3He, and then it is fed back into the fusion reactor, that fusion reactor would use only deuterium as primary input fuel and because it will fuse internally larger quantities of 3He than of tritium, it will produce a flux of neutrons significantly lower than a standard deuterium-deuterium fusion reactor, even if not so low as a reactor that could use 3He as a primary input fuel.
This idea is promising, but the conditions for deuterium-deuterium fusion are more difficult to attain than for deuterium-tritium fusion.
Moreover, all the papers that I have seen about this concentrated on the great advantages that would happen if one would remove the tritium from the reactor as soon as it is produced, but none of them mentioned the practical means to do this. Removing promptly the tritium from the plasma of a fusion reactor is something much easier said than done.
D + He3 is easier than p + B11 (in terms of required temperature and pressure) but is not so clean because you get some D + D that produces some T which then reacts with the D to make very hard neutrons.
He3 though is hard to get. If you had D + T or D + D fusion running at scale you could breed a lot of it though. He3 was proposed as a starship fuel in the 1970s Daedalus project. It’s not that hard to believe it could be made to work IF you had a heavy ion beam ignition which in turn means you make a very big ship (… like a manned starship, not a ultra-long range Voyager.)
In a D + T cycle it is easy to multiply hard neutrons to breed more T from Li.
If you've got an excess of T you can let some decay. Today we produce He3 using expired T from nuclear weapons. On a scalable basis we'd be either liquefying the T or compressing it to store it as gas, either way you'd have to remove the radioactive decay heat.
HB11 is proposing to use an "avalanche" mechanism where alpha particles from the fusion run into and accelerate protons to energies > thermal to continue the reactions (a chain reaction).
Unfortunately, this doesn't appear to work, by about two orders of magnitude.
Their proposed direct conversion scheme is also problematic, for several reasons (electrons would short out the spherical capacitor, the necessary ion current greatly exceeds the space charge limit on the current, and the alpha particles from p-11B are not monoenergetic, meaning that ions would either not have enough energy to reach the collecting electrode or would reach it with so much kinetic energy the surface of the electrode would experience too much heating.)
"Hydrogen-boron fusion doesn't create heat, it merely creates "naked" helium atoms, or alpha particles, which are missing electrons and thus positively charged. HB11 plans to simply collect that charge to create energy, rather than needing to superheat steam and drive lossy turbines. No nuclear waste is created."
> "the only commercial entity to achieve fusion so far," making it "the global frontrunner in the race to commercialize the holy grail of clean energy."
This statement does not inspire confidence. Many, many commercial companies have achieved fusion. None of course have achieved net-positive-EROEI fusion, which is what is needed for power generation.
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[ 53.7 ms ] story [ 714 ms ] thread...is this true? It's pretty trivial to achieve fusion (laughabe efficiency, but still fusion!) with a few thousand dollars and a well-funded garage. Maybe "commercial entity whose goal is to generate positive-yield fusion" is what they mean..
That could be, they don't want to deal with neutron flux for no reason.
It's definitely not true that no commercial entity has built and operated a chair.
https://www.sciencedirect.com/science/article/abs/pii/S09698...
Maybe, but that wouldn't be true either. Zap Energy has demonstrated neutron production in D-D reactions. I think Helion has, too (and possibly in D-T reactions as well?). Neither is particularly close to break-even, but then, neither are these people. It's a baffling claim.
That still sounds like an interesting project, but I would not call it trivial.
I googled a bit and found this: https://www.discovermagazine.com/the-sciences/how-to-build-a...
Still an impressive achievement, but would've not used the word "groundbreaking" IMHO. I believe that in the context of nuclear fusion that word is often used to allude at reaching an energy surplus out of the reaction.
We are not near a viable fusion reactor yet. Not close.
> "HB11 Energy’s research demonstrated that its hydrogen-boron energy technology is now four orders of magnitude away from achieving net energy gain when catalyzed by a laser," reads the press release. "This is many orders of magnitude higher than those reported by any other fusion company, most of which have not generated any reaction despite billions of dollars invested in the field.
> HB11 claims is a "world-first 'material' number of fusion reactions by a private company
So they have a result which is 10x better than they thought will be, but still way lower than stellarator etc.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8791836/
Edit: Wikipedia suggests that they were using a different method to calculate Q, only measuring the power input to plasma vs output from fusion, not including system losses. So that figure is probably not directly comparable.
> the NIF used ~477 MJ of electrical energy to get ~1.8 MJ of energy into the target to create ~1.3 MJ of fusion energy
https://en.wikipedia.org/wiki/National_Ignition_Facility#Bur...
It's interesting, at that scale. But just imagine if someone designing a power plant said that their reactor generated 10x the power calculated.
Neat, at that scale. But very strong spin.
"Durability is still a big concern" translates to "but it doesn't help, in the end."
I think we know that they will work, once they actually work.
And the main important question remains, if they will also work economically.
Thus, hot-neutron fusion is a dead end. It might be that things learned chasing hot-neutron fusion will turn out to be useful for something else, such as aneutronic fusion. But work on aneutronic fusion, itself, would be overwhelmingly more useful. Very little work is being done on aneutronic fusion.
The fact that a fusion test reactor hasn't done this yet is a flimsy point. A burning plasma test machine hasn't even been made. How would you propose blankets and shields be demonstrated if not in a burning plasma machine?
At enormous cost. Nobody even has a plan for a way to operate a fusion plant at anything close to matching fission's cost, and fission itself gets less economically competitive with each passing day.
If a fusion plant could be operated competitively, surely running the same energy collection system wrapped around a fission pile would do just as well, and thus better than existing fission plants? Try it and see!
And what of renewables? We couldn't run our society on wind and solar while still feeding everyone with the land we have without displacing millions. Even if we did, the total effort (cost) to society to build and replace terra scale machine arrays would be incredible.
Fission offers a much more dense path. But what of the proliferation and accident concerns? If you set aside quarterly profits just for a moment you might see a path for humanity to stay on its current industrial path if it takes its medicine and solves its energy crisis.
Furthermore, there is never any need to devote space exclusively to solar panels. They coexist well with buildings, where their shade extends the life of roofing material, with parking lots, where they protect cars from damaging sun, with canals and reservoirs, where they reduce evaporation, and with pasture and crop land, where they increase yield by reducing heat stress, and cut irrigation demand by reducing evaporation.
I hope you will choose in the future not to propagate falsehoods you have already been corrected on.
It has also been explained that energy from renewables is radically cheaper than from nukes. So, if building out solar were too expensive, building the nukes for the same output would be overwhelmingly moreso. But in fact cost for renewables and for storage is still in free-fall, so nukes of any sort get less competitive every day.
I think on paper, you're right that fission ought to be more commercially viable than anything any of the fusion people will be able to achieve any time soon, but I think there's at least a chance that fusion technologies will manage to get themselves regulated in a way that makes the all-in costs of fusion projects much more manageable, even if the reactor itself is more expensive, less power-dense, etc. In an NRC roundtable discussion last week, there was discussion suggesting that much of the need for, say, handling tritium, could be regulated under existing, relatively lightweight regulatory structures already in place for things like nuclear medicine waste, and it seems like both the US and UK energy regulatory authorities are pretty interested in building streamlined regulatory structures that make fusion much more approachable than fission historically has been.
Much of their cost overburden arises from corruption tax, a problem common to public works projects massively expensive enough to need buy-in from a wide range of stakeholders who then expect patronage, to be charged to extreme cost overruns and schedule slip.
Since no nuke plant has ever been built with private money, and there is no realistic prospect of one ever being built with only private money, this overburden will be lifted only when corruption has been suppressed. Then we will still have the enormous, foreseeable decommissioning cost, the very high operating cost, and the astronomical liability subsidy always omitted from cost figures, but charged to the general public.
This statement is not necessarily universally true. In particular, if one can convert the fusion energy to electricity with high efficiency (i.e., not by an ordinary thermal cycle as would be needed for the neutron energy in a DT fusion reactor), and if one could also recover the input energy to the plasma with high efficiency, then it could be practical to have a much lower Q.
Helion's scheme is like this. I understand they've demonstrated 95% recovery of plasma energy (no fusion occurring, just heating and compressing the plasma, then recovering that energy to capacitors), which is rather impressive. Their commercial 50 MW concept would have Q = 2.
Helion is the fusion company I feel most positive about, for that and other interrelated reasons.
MCF is quite close to triple product performance of a burning plasma, where self-heating becomes dominant. There is a financial hurdle going from a research device to a nuclear machine capable of burning plasma. People are doing it right now though.
https://twitter.com/jb_fusion/status/1506964692627034118
What it ignores is that tokamak output is highly nonlinear. It scales with the square of plasma volume, and the fourth power of magnetic field strength. Double the field, 16X the output. These scaling laws are very well established at this point.
The plasma volume scaling is why ITER is so big. But after ITER was designed, people invented REBCO superconducting tape, which can support much stronger magnetic fields and is commercially available.
Using those fields, CFS is building their SPARC reactor, which will get ITER-level output (Qplasma=10) from a reactor half the size of JET, which was built in four years. (Three years for the building, one year for the reactor inside.) If that goes well, the next step would be build their ARC reactor, which will be the same size as JET and get commercial-level output.
(Some of the alternate designs also have great scaling in theory, but we don't understand their plasma physics as well so it's harder to predict how they'll turn out.)
the accelerator based fusion - like accelerating protons into a solid target - is probably among the easiest ways to get some fusion. Improving it is though a completely different thing - as even the solid targets are really mostly space between the atoms (and thus the overwhelming majority of the incoming protons lose the energy by heating the target instead of hitting the target's atoms), the density of the target to achieve break even should be on the scale of like 10x density of lead. The only known ways to get such matter densities is by compressing the matter by something like X-rays of the power comparable to that of the nuke explosion generated X-rays (like for example is done in Sandia Z-machine or NIF lasers).
I'm not a physicist or a professional scientist in any way. But is this at all normal? 10 times means a whole order of magnitude. Is that a sign that the math is wrong somewhere or that some measurement is wrong somewhere?
This kind of fusion is the only kind of fusion that may be considered clean, because the risks of producing radioactive waste are negligible.
The easier kinds of fusion, which are attempted by almost all fusion research projects, e.g. the deuterium-tritium fusion, produce most of the energy in the form of high-speed neutrons, which must be absorbed by some shield. The shield will soon become radioactive, generating a lot of radioactive waste, even if it may be hoped that by choosing carefully the shield material the kind of radioactive waste that is produced may be less dangerous than the waste generated by fission reactors.
So any research results about hydrogen-boron fusion are far more important than the results about easier fusion reactions.
Unfortunately, even with these positive news, there is no clear path towards developing some kind of fusion reactor that could use this better fusion reaction.
That's like saying research results in exhaust filters was much more important than research into combustion engines back when we had none - how does that make any sense ? Disposing radioactive waste isn't impossible, it's just not trivial, if that was the only downside of fission plants I doubt many people would have a problem with them. Pollution produced by coal plants is categorically worse and yet we have those all over the place.
Any neutron shield will be destroyed in a relatively short time, so it will have to be replaced and processed for the separation of the radioactive waste.
This is certain to greatly increase the cost of operation for a fusion reactor.
Also the fusion energy carried by the neutrons will be recovered only partially, because it will be transformed in heat in the shield and taken away by a coolant and then the heat will be used in electric generators, like the heat produced by fission or by fossil fuel burning.
Because the products of an aneutronic fusion reaction are high-speed charged particles, it is theoretically possible to make a direct electric generator, without using heat as an intermediate, which could have a much higher efficiency.
Making a small fusion reactor that produces neutrons would be always impossible if living beings are close, due to the need for a neutron shield. So you will never have e.g. a car with such a fusion reactor. There are no known size limits for a fusion reactor with hydrogen-boron, so it might be possible to make reactors small enough to power a house or a vehicle.
So if it would be possible to control a fusion reaction like hydrogen-boron, it would be possible to make fusion reactors that could produce much cheaper energy than it is possible with the easier fusion reactions, for which it remains to be proven if they could become economically viable, even long after the technical problems needed to enable the production of more energy than consumed will be solved.
However, many real breaktroughs would be needed to discover how to do aneutronic fusion reactions, at the scale needed for energy production.
The easier fusion reactions, like deuterium-tritium or deuterium-deuterium, have so many intrinsic disadvantages and so little advantages over fission reactors that it does not seem likely that they could ever become the main method for energy production.
Further, Hydrogen born is also only aneutronic if the chamber is kept free from everything else to an impractical standard. So, yes in theory you don’t need neutron shielding, but in practice you very much need shielding at useful sustained power outputs. In the end you will still produce radioactive waste, just less of it.
If such fusion reactions will ever be used, some means to accelerate the nuclei will have to be used, so that they will have a directed movement not a random thermal movement.
So there will be no billion degree plasma in thermal equilibrium, radiating gamma-ray photons.
Some high-energy photons will be produced in secondary reactions, but that cannot be compared to standard fusion, where producing neutrons is the intended result of the reactions.
It cannot be predicted yet how much shielding might be needed, but in any case that would not be comparable with the needs of standard fusion.
The real problem of the hydrogen-boron fusion is that, for now, there is no known method that could ensure a high-enough probability of collisions between accelerated nuclei and a solid target or other accelerated nuclei, so that the rate of collisions would be high enough to generate more energy than consumed.
It’s not magic, you can set useful lower bounds knowing an actual reactor would be worse.
Source? To my knowledge, all radioactive waste disposal systems we have tried to this day have profoundly failed... and some even have failed years before they were scheduled to store any nuclear waste (eg. deadly gallery collapse in Bure, France).
https://www.hsfk.de/fileadmin/HSFK/hsfk_downloads/Strong_Neu...
The beauty of pB11 is that it just produces (mostly) helium, so it doesn't make the place radioactive. A very small amount of reactions result in short lived C11 (20 minutes half life) and the occasional neutron, but nowhere near the amount of DT (1 neutron per reaction).
No proliferation potential, no waste disposal problem, no dangerous fuel also lead to greatly reduced security costs. And very little decommissioning costs.
Now if it wasn't just so damn hard to ignite...
While the amount of neutrons would be so low that materials could handle them, they'd still make the reactor hot enough that hands-on maintenance would not be possible (it would make it easier on remotely operated repair machines, though.)
It's a shame none of the p-11B schemes appear to be workable. Helion's approach seems more realistic (if still a stretch) and would also greatly ease neutron levels, if not to the same extent p-11B would.
More mainstream fusion methods have to go through the typical hot water -> steam -> steam turbine route. There is a theoretical limit to the efficiency of this conversion (around 40%). In addition, the cost of electricity has a lower limit based on the capital expense of the steam turbine/generator. H-B11 fusion could be order of magnitudes cheaper.
I guess it doesn't matter so much on Earth, but for instance if you ran a fusion reactor like that on a space station. Wouldn't it become electrically charged?
The energy isn't extracted because of a build-up of charge. What happens is that each nuclear reaction is a tiny explosion. The helium nuclei shoot out really fast, and they're positively charged. You just need them to push through a magnetic field, and then you're getting electricity, like any generator moving magnets through a coil.
Having the ions move against a magnetic field doesn't change their energy. What would be needed for that scheme is to subject the ions to a changing magnetic field to produce an electric field that reduces their energy. Helion proposes something like this.
Would it be possible to use Helion's scheme for HB11 (assuming they manage net power)?
pdf: https://arxiv.org/ftp/arxiv/papers/2012/2012.14533.pdf
But also maybe there's a chance that there's a way to make it work (as your link suggests at the end). It seems to me that the initial impetus, a small explosion of charged particles, is the same for both HB11 and Helion. So it doesn't seem like it matters if HB11's energy extraction doesn't work, as long as Helion's does.
IMO the reason that HB11 may actually succeed is that the reaction keeps most of the output energy in charged particles in the plasma, so it's more feasible to achieve true ignition than when neutrons carry most of the output energy away from the plasma.
I know very little about this field - but thankfully I know just enough to understand everything you said above.
> there is no clear path towards developing some kind of fusion reactor that could use this better fusion reaction
If you have the time to spare, could you unpack this a little bit?
I'm sure many of us would appreciate the added insight.
Thanks!
People try mostly the fusion between hydrogen isotopes, or at most between hydrogen and lithium, because these nuclei have a low electric charge, 1 for hydrogen and 3 for lithium, so that the repulsion forces between them are relatively small.
When nuclei with greater electric charge are involved, e.g. boron, the repulsion forces increase. To overcome them, the nuclei must have a higher relative velocity before collision.
There are 2 ways to obtain high-speed nuclei, either by heating some plasma until the nuclei have a random thermal motion with high-enough typical velocities, or instead of heating everything and hoping for random collisions, you accelerate somehow some nuclei towards others, so that their movement is directed, not random.
It is already very difficult to contain plasma hot enough for deuterium fusion. There are very small chances for being able to contain and control the much hotter plasma that would be needed for fusion reactions with heavier nuclei.
So attempting to do hydrogen-boron fusion with the methods tried for deuterium-tritium seems doomed to fail.
The workaround is to abandon the thermal way and to search for a way to cause the fusion of accelerated nuclei, using some combination of electric fields, magnetic fields and lasers.
To produce more energy than consumed, it is required to have a very high probability that the accelerated nuclei will collide with their target (which might be fixed or also accelerated). For this either the ion beams would have to be very dense, or their positions would have to be controlled with nanometer precision or a single primary collision should cause multiple secondary collisions, or some other means would have to be discovered to ensure that the accelerated ions collide with the target instead of missing it.
All of the methods that have been imagined yet have a collision probability lower than needed by a few orders of magnitude.
So several real breakthroughs would be needed to be able to produce energy in this way.
The only hope for this is based on the fact that are no known reasons that would make this target impossible, while for the deuterium based fusion reactions there are a few serious disadvantages that are impossible to overcome, mainly caused by the facts that the energy is produced as neutrons and that deuterium and tritium have low availability.
If you want extremely low neutron production, Princeton Satellite Systems has a scheme using a field reversed configuration (like Helion) but driven by an "odd parity" rotating magnetic field. This scheme causes 3He ions to have high energy, but the D ions to not, so DD fusion is suppressed. Neutron output is claimed to be just 0.1% of the fusion output, similar to p-11B. But you'd need a source of 3He. I have a question about recovery of energy from scattered 3He ions that didn't fuse in this scheme.
It seems that there is some 3-helium stored in the core of the Earth, but only a small part of it trickles continuously to the surface. When it reaches the atmosphere without being captured, it is lost quickly to the outer space.
Because of that, 3-helium is very expensive, but more importantly, the quantity that could be extracted each year is limited.
Even if the entire flow of 3-helium from the core could be captured, the energy that could be produced would be much less than what can be produced from uranium, not even counting the much larger reserves of thorium.
There have been some speculations that there might be larger reserves of 3-helium on the Moon, so that the only possible use of deuteron-helion fusion reactors in a not too distant future might be in some Moon stations.
I have hoped there's a "Planet X" in the outer solar system that's sufficiently small to easily land on and return to space, but large enough that it could retain some primordial helium in its atmosphere. If so, it might be the best place in the solar system to obtain the isotope, assuming a D3He fusion rocket could get out there and back quickly enough.
So, at least until we will know more, there is still a chance for your hope to be fulfilled.
It is plausible to expect a larger 3-helium content there, but it cannot be estimated yet whether it would be so abundant that it would be worthwhile to extract and bring back.
In the distant future, most civilization will be in and beyond the Kuiper belt, because while energy is as cheap as a supply of 2H and 3He (and eventually H and 11B), cold is hard to get in substantial quantity except far enough from a star. We will need a lot of cold.
D + D fusion isn't that much harder than D + T fusion and it's imaginable that a scaled up version of a D + T reactor would work for D + D. (By "scaled up" imagine a large space colony with a closed ecosystem which uses D + D energy to replace sunlight.)
D + D fusion produces copious amounts of T and He3. These isotopes would burn up quickly in such a reactor but certainly some could be extracted. The He3 can be captured and used directly for fuel. The T decays with a 12 year half life. It could either be fed into D + T reactors or allowed to decay to produce more He 3.
The best use for D + He3 imagined yet is something like
https://en.wikipedia.org/wiki/Project_Daedalus
which might be realizable with heavy ion ignition but the ignition system would be physically large which would scale the whole spacecraft up to "manned interstellar colonizer" as opposed to "very long range Voyager."
Now a D + D culture would already be "interstellar" in that it could support large populations in the spaces between the stars. A civilization like that would be able to cross from one star to another in 10,000 years or so but they might not care at all because they can live their lifestyle just fine without stars. Thus they might not be that motivated to develop in-a-human-lifetime interstellar travel.
Note a D + T fusion economy also could produce large amounts of He3 if that was wanted because a D + T economy is going to breed large amounts of T from lithium. If some of that is allowed to decay you get He3 which can be diverted to whatever use people have for it.
Adding up those options I think the trace quantities of He3 that might turn up away from Earth don't move the needle.
It seems likely that the atmosphere of Neptune has a useful fraction of 3He. But you need to get there first, with apparatus to collect it. For that, you probably need a fusion rocket, and 3He to burn in it.
Making the tritium requires another fusion or fission reactor, in which case there is no point in trying to develop a 3He fusion reactor, because it will be advantageous only if it can replace the fission reactors and the "dirty" fusion reactors.
If those are still needed to produce the nuclear fuel, nothing is gained by using 3He.
If there would have existed a natural source of sufficient 3He, then things would have been very different and the deuterium-3He fusion would have been the top priority in fusion research.
A much more likely use of 3He is inside the so-called tritium-suppressed deuterium-deuterium fusion reactors.
The deuterium-deuterium reactions produce both tritium and 3He. If the tritium is removed continuously from the fusion reactor, then it is stored for a long enough time until it decays into 3He, and then it is fed back into the fusion reactor, that fusion reactor would use only deuterium as primary input fuel and because it will fuse internally larger quantities of 3He than of tritium, it will produce a flux of neutrons significantly lower than a standard deuterium-deuterium fusion reactor, even if not so low as a reactor that could use 3He as a primary input fuel.
This idea is promising, but the conditions for deuterium-deuterium fusion are more difficult to attain than for deuterium-tritium fusion.
Moreover, all the papers that I have seen about this concentrated on the great advantages that would happen if one would remove the tritium from the reactor as soon as it is produced, but none of them mentioned the practical means to do this. Removing promptly the tritium from the plasma of a fusion reactor is something much easier said than done.
It is yet to be seen whether remote laser or local fusion will be more useful for powering outer-solar-system spacecraft.
If you only need neutrons to make 3H, they don't need to be hot, and are more useful cold.
He3 though is hard to get. If you had D + T or D + D fusion running at scale you could breed a lot of it though. He3 was proposed as a starship fuel in the 1970s Daedalus project. It’s not that hard to believe it could be made to work IF you had a heavy ion beam ignition which in turn means you make a very big ship (… like a manned starship, not a ultra-long range Voyager.)
If you've got an excess of T you can let some decay. Today we produce He3 using expired T from nuclear weapons. On a scalable basis we'd be either liquefying the T or compressing it to store it as gas, either way you'd have to remove the radioactive decay heat.
Unfortunately, this doesn't appear to work, by about two orders of magnitude.
https://iopscience.iop.org/article/10.1088/1361-6587/abf255
Their proposed direct conversion scheme is also problematic, for several reasons (electrons would short out the spherical capacitor, the necessary ion current greatly exceeds the space charge limit on the current, and the alpha particles from p-11B are not monoenergetic, meaning that ions would either not have enough energy to reach the collecting electrode or would reach it with so much kinetic energy the surface of the electrode would experience too much heating.)
How is this charge collected ?
It’s getting more energy from fusion than it takes to start the reaction that is special.
This statement does not inspire confidence. Many, many commercial companies have achieved fusion. None of course have achieved net-positive-EROEI fusion, which is what is needed for power generation.