To be fair, that's not entirely the fault of HN. It's hard to get excited about fusion research when I almost always feel mislead, because it is almost never explicitly stated that we are talking about Q-plasma here. I don't expect much from science journalism, but I feel that the fusion scientists have no problem silently playing along this misconception, which they are perfectly aware of.
That is the way to keep the money flowing.
See
"How close is nuclear fusion power?" https://www.youtube.com/watch?v=LJ4W1g-6JiY
and (different area but about how high investment physics works, "just around the corner")
That device in the photo is great. Looks to be about 16AWG magnet wire. Guessing a 10mm ID of the coil, and about 25mm in length. To get to 26 Tesla, looks like you'd need to push about 33,000 A through that coil. Coil inductance might be about 1uH, and if the test lasts ~1us, then you'd need 33kV to push that 33kA through the coil. 30kV/inch insulation resistance, might not get arcing between the wires in air. Probably running the thing in vacuum? Looks like things check out.
https://www.eeweb.com/tools/magnetic-field-calculator/
>NIF has uncovered some new science
What is the new science? Seems like they are working on making the fuel pellets closer to perfect, which makes sense if you are trying to use the implosion shock wave inside the fuel to be the source of heat and pressure needed for further fusion. I'm imagining that the laser initiates the surface fusion, and then you want that fusion to propagate inward, and need thing perfect, so the fuel doesn't go squirting out the sides (so to speak) stopping the chain reaction.
https://www.llnl.gov/news/three-peer-reviewed-papers-highlig...
In particular, the original article talks about magnetic compression hypothesis being a byproduct of white dwarf simulation. With this new regime, they were able to apply the same ideas to fusion, resulting in the breakthrough.
With ignition being a regular thing in laser fusion going forward, I suspect many groups will have some slightly varied approach or some technique improvements.
If you're into fusion and lasers, there's a lot of areas that are still ripe for magnitude leaps.
- Laser power, timing, materials, and cost
- Metallurgy of the target canister
- Construction of the target and perfecting it as you mentioned
- Absorption of energy
I believe the NIF will focus on #2 and #3 as of course they focus more on making the "boom bigger" rather than making it cost effective of useful. IMO another group (startup or otherwise) will step in as an actual project in this space.
One area to innovate here is to use a different fuel mixture that doesn't produce neutrons. We wouldn't need liquid lithium/lead, breeding, or any of the complexities people very commonly complain about.
- https://en.wikipedia.org/wiki/Aneutronic_fusion
- https://en.wikipedia.org/wiki/Direct_energy_conversion
It's entirely within the realm of possibility that the technique to achieve ignition will open the door for 5:1 or 10:1 q with neutron-free fuels.
Even a total Q of 2:1 or 3:1 is a huge win, and that's within a magnitude of the modern tech.
--
Something I want to mention here too - the easiest aneutronic fuel mixture available is H2 + He3. It hasn't been explored too much since He3 is hard to come by on earth (though you can mine it from the moon!).
But, Helion has patented a way to generate He3 from H2 fusions. We don't need to mine He3 to achieve neutron-free fuels, just need to transmute it from seawater.
That is the coolest thing I'll read all month.
The patent was based on research analyzing the propagation of wavefronts on neutron stars[1]. I forget the term(s), but the critical aspect related to features which travel along the wavefront faster than light. This feature couldn't actually be used to communicate faster than light, obviously, however the patent claimed to be able to use it to defeat active radar jamming--more specifically, radar deception. Because this controllable wavefront feature (modulation? polarization?) could be FTL, and the waves themselves light-speed, it was thus intrinsically impossible to fake a correct return signature.
From a lay geek's perspective, I told my friend that AFAICT this aspect of the invention seemed not obviously flawed: it was FTL only in the sense that you could swing a flashlight across the moon and the apparent motion of the reflected beam could be faster than light. Normally such a phenomenon is merely a curiosity, but apparently the inventors had put it to some practical use, at least in theory.
[1] IIRC, either physical or magnetic waves generated by starquakes.
https://en.wikipedia.org/wiki/Phase_velocity
You can see the effect shown in the first animation of this article if you keep track of the wave peaks in the wake of a boat. They start at the back of the group of waves, move through it, and fade away as they reach the front.
Yes it does indeed. Amazing amount of trial and error to build such a machine.
People who want to prevent arcing flood the cavity with sulfur hexafluoride. Fun fact, it has 25,000 times the "greenhouse potential" of CO2. Dunno if that includes lifetime in the atmosphere, or just instantaneous opacity to IR. All the wind turbines are pumped full of it. There is an effort on to switch to something else of proprietary composition.
It's probably not feasible to pump to such low pressures in wind turbines, so they probably don't even try. But for NIF, it's common.
Provide links? Also, 25000 times might be ok, if the amount of gas released in the atmosphere is 1/10^6, say, of the amount of co2
"Data from Vattenfall suggests leakage emissions from Europe’s 100,000 wind turbines were about 900kg of SF6 over the last six years. This is equivalent to 3,525 tonnes of CO2 a year. This includes the release of gases during the reclamation and recycling process. At end-of-life the turbine switchgears are collected and the sulphur hexafluoride gas is reclaimed and reused in new equipment.
By comparison wind energy avoids the emission of 255 million tonnes of CO2 in Europe a year by generating 336TWh of electricity displacing fossil fuels. The SF6 leakage therefore represents around 0.001% of the emissions avoided thanks to wind energy every year."
individual wind turbines are not generating at more than 13.8kV so I would be surprised if they had any sf6 in them.
In order to make inertial confinement work, this process needs to occur multiple times per second
All the fancy stuff with the hohlraum, magnetic compression, target cryo cooling must be accomplished accurately and repeatedly, BUT ALSO shot out of an "injector" to fall precisely into alignment with the lasers, in vacuum within a plasma field...
When you write it all out! Yikes!
Then! This has not included any capture of energy, so that part must be implemented as well, which would effectively mean placing all of NIF target chamber inside a thermal heat exchanger.
So, no, inertial confinement is probably the furthest from ever being a suitable arrangement from a power production standpoint.
Physicists have an uncanny ability to ignore engineering.
As a proponent of fusion and fusion research, it's important to keep the focus on what is valuable about the work being done and not mislead the general public about flights of fancy.
If you want to understand radiative pressure and plasma characteristics, this is the place to be, for sure
https://www.youtube.com/watch?v=5Ge2RcvDlgw
Probably the hardest part is making sure the droplet is cost effective enough that we care.
Again, to op's point, this is an incredibly shallow analysis. The question I would be pushing towards is:
What are the hardest remaining engineering problems? How likely are we to overcome them? At the end of that process will it be a cost competitive outcome?
The laser does not hit the target, it hits the interior of the hohlraum. Generating x-rays, this creates radiation pressure on the cryogenically cooled target, which is inadequate for fusion without also pulsing a high magnetic field to confine the plasma (this is now inertial/magnetic confinement fusion).
The energy output is not sustained for any duration, but rather is nearly instantaneous. The plasma and debris must be cleared of the beam path for the next laser pulse and target injection.
These are the hardest remaining engineering problems if you discount the fact that energy must then be absorbed and put to use with constant material degradation of the target chamber and the necessary high output production of tritium filled beryllium capsules.
We are unlikely to overcome these challenges for substantially longer than the time period required to generate a functioning EUV machine.
It does sound like magic, but doesn't EUV involve some process similar to this? Something about shooting drops of tin with a laser? That sounds like magic to me too but is apparently a thing. Obviously two totally different things, but the level of magic to me is the same.
That means the reaction would only need a gain of 4, rather than 100, to generate net power.
JET Tokamak was within a factor of 2 and ITER will overshoot by a factor of 10.
My lazy quick skim of the main article here is that NIF has achieved a Q value of 1.2 presently.
ITER is aiming for a Q of 10 [0]; i.e. Q=10 means fusion outputting 10x the input energy, which is (by some considered) roughly enough to break-even in energy production [1], i.e. to recapture 10% of that energy (as heat or as electricity, not sure...)
So parent poster saying NIF is an order of magnitude away means Q=1.2 -> ~Q=10
And ITER seeking Q=10, means that's the goal that NIF is an order of magnitude away from, according to the parent poster.
[0] Q=10 for Iter: https://www.iter.org/sci/Goals#:~:text=ITER%20is%20designed%....
[1] Q=10 is a rough minimum for energy production (quick and dirty source from google) https://www.powermag.com/fusion-energy-is-coming-and-maybe-s....
1. It is, purely, bomb research dressed up as civilian activity for funding purposes. Everyone working on it has top-secret clearance.
2. It has no consequence for any civilian project. The target that produced a couple of MJ cost $10M. (2.4 MJ is <0.7 kWh.) A real plant would need to feed them in at a high rate. Q is not the important measure. Dollars out / dollars in is the right measure, and everyone is still at exactly zero, with no plausible prospect of ever exceeding 1.
3. Extracting useful energy would require capturing hot neutrons in a "blanket", heating it up, and running fluid through it to boil water to drive a steam turbine. The minimum practical size for such a "blanket" exceeds that of a large fission plant. To collect enough neutrons to be useful requires a huge volume of plasma, as even compressed plasma is very diffuse vs. fissiles.
4. Compressing the plasma with superconducting magnets could increase density, but then the neutron flux through the smaller surface area of the chamber wall would destroy it that much more quickly.
5. The hot neutron flux would also quickly weaken the structural parts required to contain the enormous forces exerted by the electromagnetic coils. Superconducting coils would impose even larger stresses. No research has gone into identifying a viable material, in decades, despite that none is known. After a short time the reactor parts would all become weak and (also) fiercely radioactive. Repairs would need robots not yet designed.
6. Civil fusion would require a large amount of tritium, which no one knows how to make economically.
7. Steam turbines cost a lot to operate, regardless of heat source. No other generation method relying on such steam turbines -- coal, fission, geo -- is today competitive vs. renewables. As the cost of renewables continues on down, they get less competitive by the day.
Fusion is intrinsically interesting, just not for power generation.
One company, Helion, is trying to make a fusion device that does not emit many hot neutrons. However, achieving conditions for this process, D-3He, is even harder than for D-T fusion. They hope to breed their own tritium, which would eventually decay to the 3He they actually need, but it is not clear how they will produce enough. (Fun fact, 3He loves to turn back into tritium.)
If they cannot, but they do get it working, it might end up usable for outer solar system exploration, which is difficult to power.
This "milestone" provides exactly zero meaningful information for the magnetic confinement fusion that is the only avenue being pursued for civil power.
Fusion offers no prospect of "unlimited free energy". It offers instead very expensive energy, or possibly none at all. We already have access to unlimited free energy, and need only build out the solar, wind, and maybe tidal systems to collect some as it goes by.
2. Again, all technology is expensive in the beginning. Who cares? The important thing here is to climb magnitude by magnitude. NIF climbed many magnitudes in recent history, making it notable.
3. As you mentioned, Helion and direct energy capture. D+He3 + DEC might be not feasible with a tokamak, but the scaling laws of fusion (size, current, B field) are in favor of experiments that get close.
4. See 3
5. See 3
6. See 3
7: See 3
I think you have a very negative take on what is an amazing breakthrough accomplishment. Even if the NIF doesn't end up converting their research into a commercial powerplant, they have at least demonstrated experimental viability of inertial confinement fusion. It's only a matter of time before the next generation shows viability of D+He3 fusion and then we'll have even more options.
You may call it a "milestone" if you like, even though it is a milestone on the way to nowhere. The only reason fusion gets any attention is because megaton bombs worked, and already demonstrated Q>1.
People are building out solar and wind power systems that stand some chance of fending off climate catastrophe, each day pushing fusion, like fission, farther from any prospect of competitiveness.
The consequences of a breakthrough are often not noted at the time. It is only when the consequences have happened that we recognize them and grasp the change which has been catalyzed by the discovery. Who, other than Mathematicians, cared about Number Theory when it was discovered?
I don't know enough about plasma physics to characterize this one way or the other, but I think looking for notable consequences is very slippy ground to stand on when dismissing a result.
along with 1.3 million others [0]. just sayin'
[0] https://news.clearancejobs.com/2022/08/16/how-many-people-ha...
But that they don't hire anybody without still tells us something.
These sorts of hard questions about scaling it up into real life have been some of the most persuasive fusion critiques.
And the bit you tapped into about the whole detachment from the gov research world from making something they have to justify with hard $$ and all that comes with it are very legitimate.
Mostly Agreed: there may be applications such experimental astrophysics, but that's certainly not the main motivation.
> 2. It has no consequence for any civilian project. The target that produced a couple of MJ cost $10M. (2.4 MJ is <0.7 kWh.) A real plant would need to feed them in at a high rate. Q is not the important measure. Dollars out / dollars in is the right measure, and everyone is still at exactly zero, with no plausible prospect of ever exceeding 1.
The cost of just about anything new regarding fusion experiments is not very meaningful: likely it had to be invented, designed and manufactured just for them. Of course it's crazy expensive, but it doesn't mean prices won't go down after an industry around fusion has been established. Just look at the price of a c-Si solar cell in the 70s.
> 5. No research has gone into identifying a viable material, in decades, despite that none is known. After a short time the reactor parts would all become weak and (also) fiercely radioactive.
I don't know about inertial confinement, but in magnetic fusion that is completely false. Materials with low activation, radiation damage resistance and good plasma properties have been continuously researched for the last 30 years: the current candidate for ITER is EUROFER97 for which you can find almost 800 publications. [1]
> 5. Repairs would need robots not yet designed.
Also false. Not only there are several remote handling designs for DEMO power plants, but they have also existed for a long time. For example, JET had been operated remotely since 1997, during the DT1 campaign. [2]
> 6. Civil fusion would require a large amount of tritium, which no one knows how to make economically.
Well, this is dishonest. Of course no one knows how to breed tritium economically: we don't know what the economy will look like in 40-50 years, but we surely know how to do it.
Fusion power plants are designed for self-sufficiency, producing more tritium that they consume by a factor of at least 1.05 (called tritium breeding ratio). Very briefly, this involves a breeding blanket that converts lithium to tritium and a complex chemical plant to extracts newly produced tritium from the blanket and also recovers it from the unburnt plasma fraction. See [3] for an overview of various design that will be tested in ITER.
For as long as there are a few CANDU reactors around, the current tritium supply will be enough to bootstrap future fusion plants without expensive ad-hoc production. [4]
[1]: https://www.journals.elsevier.com/nuclear-materials-and-ener...
[2]: https://yewtu.be/watch?v=hg6MnjG7m6U
2. Robots for fuel handling in a JET reactor are as far from robots for fusion plant repair as a Sopwith Camel is from Artemis. All they share is the word "robot".
3. Nobody can suggest any way to separate, every day, a few grams of tritium at PPB concentration from a thousand tons of molten FLiBe and lead.
I worked as a control systems engineer in the nuclear power industry for 8 years back in the '90s. I worked on Lungmen in Taiwan, ABWRs (Kashiwazaki 6/7) and even Fukushima (power uprates) in Japan and Grand Gulf and Pilgrim in the USA.
Fusion is billed as a "clean" alternative to fission reactors but I think this is (another) false hope of the technology. I still recall my nuke prof telling me that fusion (if it ever works) is going to be an even bigger waste problem than fission reactors. The 15 MEV neutrons are going to neutron-activate tons of shielding or heat extracting blankets which would be a huge disposal problem. He also thought that neutron embrittlement of plant structures was going to be a serious problem and is already a problem in fission plant cores that use thermal neutrons. Carting that waste away at EOL will kill the economics.
We should start building fission plants now which are safe and clean enough and can provide power until something better comes along.
Fission is distinguished by being the most expensive power in current heavy use. All the nukes will be mothballed, soon enough, unable find takers at a price that would pay for continued operation.
https://www.world-nuclear-news.org/Articles/First-Light-team...
Fusion has the strong advantage (and disadvantage) that it is a powerful neutron source. Even a very low performance reactor can be useful as a neutron source
https://ats-fns.fi/images/files/2019/syp2019/presentations/T...
Fusion might be useful for making isotopes long before it is competitive as an energy source. In the 1980s I know scientists were looking to hybrid systems that convert ²³²Th to ²³³U and ²³⁸U to ²³⁹Pu as fusion reactors produce so many high energy neutrons that they could be better than fast breeders for manufacturing fuel for thermal fission reactors. In fact, it is very possible a fusion reactor could be used to make fuel for nuclear weapons.
We see these comments on every science thread because almost all of these people lack the requisite expertise to weigh in on the actual details, so instead they make a high-level criticism to give the appearance of having some kind of knowledge on the subject. Moreover, they think that crapping on things equates to being a critical thinker, and have convinced one another that this is so.
I have no experience in fusion, so can't comment on that either way.
If the people working on it today want to make beef with someone, they should complain to the people who have been lying for long enough that a joke about it is at least three decades old. If the real problem is that the only way we’ve gotten funding for this is to keep misleading politicians on how long the remaining road is, that’s fine, but once you’re known for lying - intergenerationally - how on earth do you expect the general public to take anything you say seriously?
You mean, starting from the journalists writing the articles?
The article is old news before it was written. The article mentions the previous 'success' (yield was higher than previous experiments), and that was over a year ago now. They haven't been able to reproduce the previous experiment even knowing as precisely as they can what they perceive to be the preconditions necessary for an effective reaction. It also seems that this article was written about a single experiment. They will not be able to intentionally repeat the experiment. The manner in which they're exploring the pareto front is like groping in the dark to find a light switch that has an unknown texture and conformation. It's a classic monte-carlo simulation but they have one iteration every several weeks or months, and they cannot even possibly identify all the controlling parameters, nor do they have the necessary throughput or bandwidth to succeed in their pursuit without windfall.
The low hanging fruit providing the basic harmonics of the solution were discovered well before I was even introduced to this technology (in the 70's and 80's. Coincidentally around the moment of the genesis of many of our modern treaties on weapons testing).
You are overly optimistic, a 40-60% increase in nearly nothing is still nearly nothing. The PR campaign around this event is I think more significant in its political convenience, and in white washing the purpose of the facility. There are significant discoveries that still need to be made to even make the reactions consistent, and they will not come conveniently or quickly. Once the reactions are better understood and the mechanisms can be manipulated with intent the distance between the science and a practical industry / commercial product will require even more hurdles that stretch the imagination to be overcome. For instance I cannot conceive of a practical mechanism for actually utilizing any fraction of the massive amount of energy released in a fraction of a second in a chaotic murder of wavelengths and particles. The most practical way we've yet discovered for converting neutrons to electricity is through boiling water. Grossly inefficient in other contexts, I'm not sure that has even marginal utility in this scope.
I for one am 100% sure I barely know what I'm talking about. My disclaimer is that I'm not a physics guy, and high energy density physics was only a hobby of mine at one brief point in my life. Through perspicacity and access to papers and people, this is my honest mental model of the whole thing. You're welcome to your perspective, but although you seem well informed you sound very inexperienced.
> Very disappointed by the discourse in this HN thread. The same old quips over and over. "NIF is just a nuclear stewardship program", "it's not actually generating power", "fusion still 30 years away".
Basically, I came to the comments to hear from the skeptics. Of course, most of the skeptics fall victim to a mental trap.
I think there is one key difference between "what I was looking to read from skeptics" and "what most skeptics used as arguments". The information I was seeking: to understand the difference between what the "breakthrough" was being reported as and what the breakthrough actually was. The information I received was: "this is impossible for (reasons)"
An equally important thing I was seeking was to understand was how this work might affect other industries (before it results in "fusion power").
The thing I'm least interested in is hearing "why it will never happen." I think most of us know many of the reasons this is a "Marsshot" problem[1]. I think most of us get annoyed when the media presents news in a manner that provides the general public with extremely unrealistic expectations and are sensitive to the dangers of that, but we get frustrated by those kinds of comments because, likely, none of us need to be told that! :)
It's impossible to make a useful argument to a skeptic that "this technology will exist in (insert timeframe)." The point at which (timeframe) is a trustworthy estimate usually coincides with the technology maturing to the point that the skeptics fall off (or turn out to be right if "timeframe" is never). And there's a long way to go (I think I saw a list of 10 or so "extremely hard problems") but this certainly appears to be something that is chipping away at one of the "impossible problems." Over-simplifying as this is, the rate at which technology advances is not linear; it accelerates. The next problem may not be as difficult or knowledge we attain from solving this one may be able to be used to solve related problems[2].
[0] There were several others on the topic and being ft.com, I assumed it would require a subscription that I do not have.
[1] Maybe far more difficult, but I never liked "moonshot" when describing something that hasn't been done, yet.
[2] Again, not a physicist, but reading through various "fusion is doomed" lists, many of the problems center around "the word 'hot' is a woefully inadequate description".
Before this is not solved:
"it's not actually generating power"
I simply would not talk about a real power plant yet, because a real power plant has economic constraints. As long as the current approach is not even generating energy, all the scepticism is warranted, if we are talking about something that is supposed to solve energy generation and climate change. This is why people are upset with it - we need not promises of unsolved tech, but solutions now. So fusion remains exciting and cool tech and I love to read about its recent progress, but please without illusions. Even if they could generate power tommorow - it would still be a very long, unknown way, till it actually helps us.
https://coldfusionnow.org/power-equivalent-to-the-sun-we-alr...
This is one aspect of the problem. THe another aspect is that we should create decentralized technology that everybody can use at home. It would make our world a much better place, much more resistant to many things (including terrorism). I think the small amount of virtually infinite energy is a much better option.
I think it's very clear, given the past year that NIF has had, that they are very rapidly approaching a point where we have the tech to "solve" inertial fusion.
https://lasers.llnl.gov/news/papers-presentations
Getting fusion right is done a magnitude at a time. Right now NIF is within 1 magnitude if they built it with modern laser tech. Many fusion designs are 10 magnitudes away or more.
Their most recent article has a ton of great data and next steps:
https://lasers.llnl.gov/news/magnetized-targets-boost-nif-im...
This includes
- Cryo-cooling the main target
- New alloys
- Magnetic compression of targets
The recent advancement that helped reach ignition (in the last article) boosted performance 40%.
The advancement between then and now: nearly 60%.
Within the past 6 months, NIF has nearly doubled energy output of the reaction.
Plus, if you know anything about fusion research, you'd know that energy outputs tend to scale non-linearly with energy input and size. This tends to be on the order of the power 3 or 4. Hence the existence of ITER.
NIF has uncovered some new science, closed the magnitude gap, and made it actually realistic for inertial confinement to be a feasible tech for a power producing plant.