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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 generati

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". 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 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-implosion-performance 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.

zackees 4y ago
devin 4y ago
I am not a physicist. Most here aren’t but fancy themselves experts on things they know precious little about. I’m not surprised but I agree it’s disappointing.
floxy 4y ago
>Their most recent article has a ton of great data and next steps: 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/ 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.
- donquixote25 4y ago
  Yea, the whole target bay is in vacuum which helps with the arcing.
  - moloch-hai 4y ago
    Vacuum is supposed to increase arcing. 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.
    - donquixote25 4y ago
      That is only true to a certain point. Look up Paschen's law. After you go lower than a certain point, around 10 Torr cm depending on the gas, decreasing pressure increases the breakdown voltage. 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.
    - Gud 4y ago
      I don’t know about the actual turbines, but there is GIS switchgear and it’s sealed. Modern GIS don’t leak much(extremely little).
    - liketochill 4y ago
      A breaker can use sf6 gas but usually that is at 60 kV and above. For 35 kV and below vacuum bottle breakers are much cheaper than sf6. individual wind turbines are not generating at more than 13.8kV so I would be surprised if they had any sf6 in them.
    - mavhc 4y ago
      They're not pumped full of it though, are they. "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."
SantalBlush 4y ago
>Very disappointed by the discourse in this HN thread. The same old quips over and over. 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.
- deleted 4y ago
  [deleted]
- wingworks 4y ago
  They're probably going by past experience in other tech products, which get development news but then you never heard about it again, or, if your lucky it hits consumer markets like 10 years later. I have no experience in fusion, so can't comment on that either way.
  - hinkley 4y ago
    I have thirty years of experience with people telling me we’re really close on fusion. Next year or the one after will mark my 30th anniversary of having heard the phrase, “fusion is 30 years away and always will be.” 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?
- hyperbovine 4y ago
  I regret that I have but one upvote to give.
- anshumankmr 4y ago
  Quite true. And this is something I have been quite guilty of myself.
mjfl 4y ago
> Many fusion designs are 10 magnitudes away or more. JET Tokamak was within a factor of 2 and ITER will overshoot by a factor of 10.
- gertlex 4y ago
  I think you and the parent poster may be talking about different "goals". 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%20to%20yield,MW%20of%20input%20heating%20power 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-sooner-than-you-think/#:~:text=Q%20%3D%201%20represents%20the%20breakeven,above%2010%20to%20be%20economic https://www.powermag.com/fusion-energy-is-coming-and-maybe-s....
moloch-hai 4y ago
There is nothing disappointing in skepticism about the importance or value of this work. 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.
StreamBright 4y ago
Do you realize that this is 50% of the problem? The another 50% is how to "compress" fusion? https://coldfusionnow.org/power-equivalent-to-the-sun-we-already-have-it/ 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. https://ndb.technology/ https://ndb.technology/
deng 4y ago
> Very disappointed by the discourse in this HN thread. The same old quips over and over. 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.
- limaoscarjuliet 4y ago
  Plus, this is about 10-th time in the last 10 years we are told "we are around the corner, clean energy will save us". Please tune down the message.
  - fidelramos 4y ago
    I like how this graph describes why nuclear fusion technology always seems to be "just around the corner": https://imgur.com/a/59NO34a https://imgur.com/a/59NO34a
    - cptaj 4y ago
      I really hate what hippies did to nuclear energy. We would've long solved the clean energy problem by now if they hadn't violently opposed anything with the word nuclear
      - galuggus 4y ago
        nuclear energy is an existential threat to the green movement
        bheadmaster 4y ago
        green movement is an existential thread to nuclear energy
    - fnordpiglet 4y ago
ej3 4y ago
In my youth, I was familiar with the facility that came before NIF, built in the 70's the goal at the time was to use a smaller target to demonstrate that the foundational principles that would underpin the success of NIF would work. As far as I know, they never succeeded. NIF was built anyway because this type of device is well suited to allowing access to certain types or demonstrations of physics that are otherwise unaccessible and important in a specific field of research not directly related to the flourishing of our race. 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.
hutzlibu 4y ago
"and made it actually realistic for inertial confinement to be a feasible tech for a power producing plant." 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.
crest 4y ago
Even a 100x fusion gain wouldn't make the NIF net power producer, because last time I checked the lasers produce ~99% heat and <1% coherent light. The relevant metric is the ratio of energy input into the facility vs its output.
- BawsMcGee 4y ago
  NIF was never intended to produce net power output. It's a research facility. The latest result is a major milestone demonstrating that net energy gain is achievable. LLNL, and other labs, are developing diode-pumped laser systems which are closer to 25% efficient, rather than 1%, and can operate at the high repetition rate required for power production. That means the reaction would only need a gain of 4, rather than 100, to generate net power.
- boringg 4y ago
  Couldn't you use waste heat recovery to recoup some of the lost heat from lasers? I haven't ever ventured down that route and a I don't know the scale of heat here or quality of it. Think combined cycle gas plants. I recognize totally different tech but offering ways to get some value back.
mdip 4y ago
> 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". The interesting thing here is that every part of what you said I completely agree with. My behavior, however, indicates otherwise. I didn't read the article[0]. I went directly to the HN comments mostly because I wanted to cut through the hype. 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".
- moloch-hai 4y ago
  The key is that it is not a breakthrough at all. Breakthroughs have consequences, and this will have none. Soon they will claim "Q>5", "Q>10", etc. all equally inconsequential.
icare_1er 4y ago
HN is generally more excited in a minor release of well-known libraries or of GNOME, than in medical, space, or biology breakthroughs.
upsidesinclude 4y ago
Here's the thing: 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
- Unklejoe 4y ago
  > BUT ALSO shot out of an "injector" to fall precisely into alignment with the lasers, in vacuum within a plasma field... 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.
  - PaulHoule 4y ago
    The tin is reaching 400,000 K, a fusion reactor has to attain more like 100,000,000 K.
- zbobet2012 4y ago
  All of the problems you just described are solved for in EUV lightsources for lithography on chips at 100khz or more. These are less hard then you make them sound. https://www.youtube.com/watch?v=5Ge2RcvDlgw 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?
PaulHoule 4y ago
I get disappointed that I can't get interest in stories like https://www.world-nuclear-news.org/Articles/First-Light-teams-up-with-CNL-on-tritium-productio 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/TSS2_TLinden_ConstructingAFarnsworth-hirschFusorForNeutronGeneration.pdf 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.
AtNightWeCode 4y ago
Fusion energy is a holy grail in the field of nuclear power. The claims though out the years have been ridiculous. I think it is just natural that people are skeptical.

zackees 4y ago

devin 4y ago

I am not a physicist. Most here aren’t but fancy themselves experts on things they know precious little about. I’m not surprised but I agree it’s disappointing.

floxy 4y ago

>Their most recent article has a ton of great data and next steps: 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/ 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.

donquixote25 4y ago
Yea, the whole target bay is in vacuum which helps with the arcing.
- moloch-hai 4y ago
  Vacuum is supposed to increase arcing. 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.
  - donquixote25 4y ago
    That is only true to a certain point. Look up Paschen's law. After you go lower than a certain point, around 10 Torr cm depending on the gas, decreasing pressure increases the breakdown voltage. 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.
  - Gud 4y ago
    I don’t know about the actual turbines, but there is GIS switchgear and it’s sealed. Modern GIS don’t leak much(extremely little).
  - liketochill 4y ago
    A breaker can use sf6 gas but usually that is at 60 kV and above. For 35 kV and below vacuum bottle breakers are much cheaper than sf6. individual wind turbines are not generating at more than 13.8kV so I would be surprised if they had any sf6 in them.
  - mavhc 4y ago
    They're not pumped full of it though, are they. "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."

SantalBlush 4y ago

>Very disappointed by the discourse in this HN thread. The same old quips over and over. 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.

deleted 4y ago
[deleted]
wingworks 4y ago
They're probably going by past experience in other tech products, which get development news but then you never heard about it again, or, if your lucky it hits consumer markets like 10 years later. I have no experience in fusion, so can't comment on that either way.
- hinkley 4y ago
  I have thirty years of experience with people telling me we’re really close on fusion. Next year or the one after will mark my 30th anniversary of having heard the phrase, “fusion is 30 years away and always will be.” 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?
hyperbovine 4y ago
I regret that I have but one upvote to give.
anshumankmr 4y ago
Quite true. And this is something I have been quite guilty of myself.

mjfl 4y ago

> Many fusion designs are 10 magnitudes away or more. JET Tokamak was within a factor of 2 and ITER will overshoot by a factor of 10.

gertlex 4y ago
I think you and the parent poster may be talking about different "goals". 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%20to%20yield,MW%20of%20input%20heating%20power 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-sooner-than-you-think/#:~:text=Q%20%3D%201%20represents%20the%20breakeven,above%2010%20to%20be%20economic https://www.powermag.com/fusion-energy-is-coming-and-maybe-s....

moloch-hai 4y ago

There is nothing disappointing in skepticism about the importance or value of this work. 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.

StreamBright 4y ago

Do you realize that this is 50% of the problem? The another 50% is how to "compress" fusion? https://coldfusionnow.org/power-equivalent-to-the-sun-we-already-have-it/ 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. https://ndb.technology/ https://ndb.technology/

deng 4y ago

> Very disappointed by the discourse in this HN thread. The same old quips over and over. 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.

limaoscarjuliet 4y ago
Plus, this is about 10-th time in the last 10 years we are told "we are around the corner, clean energy will save us". Please tune down the message.
- fidelramos 4y ago
  I like how this graph describes why nuclear fusion technology always seems to be "just around the corner": https://imgur.com/a/59NO34a https://imgur.com/a/59NO34a
  - cptaj 4y ago
    I really hate what hippies did to nuclear energy. We would've long solved the clean energy problem by now if they hadn't violently opposed anything with the word nuclear
    - galuggus 4y ago
      nuclear energy is an existential threat to the green movement
      - bheadmaster 4y ago
        green movement is an existential thread to nuclear energy
  - fnordpiglet 4y ago

ej3 4y ago

In my youth, I was familiar with the facility that came before NIF, built in the 70's the goal at the time was to use a smaller target to demonstrate that the foundational principles that would underpin the success of NIF would work. As far as I know, they never succeeded. NIF was built anyway because this type of device is well suited to allowing access to certain types or demonstrations of physics that are otherwise unaccessible and important in a specific field of research not directly related to the flourishing of our race. 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.

hutzlibu 4y ago

"and made it actually realistic for inertial confinement to be a feasible tech for a power producing plant." 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.

crest 4y ago

Even a 100x fusion gain wouldn't make the NIF net power producer, because last time I checked the lasers produce ~99% heat and <1% coherent light. The relevant metric is the ratio of energy input into the facility vs its output.

BawsMcGee 4y ago
NIF was never intended to produce net power output. It's a research facility. The latest result is a major milestone demonstrating that net energy gain is achievable. LLNL, and other labs, are developing diode-pumped laser systems which are closer to 25% efficient, rather than 1%, and can operate at the high repetition rate required for power production. That means the reaction would only need a gain of 4, rather than 100, to generate net power.
boringg 4y ago
Couldn't you use waste heat recovery to recoup some of the lost heat from lasers? I haven't ever ventured down that route and a I don't know the scale of heat here or quality of it. Think combined cycle gas plants. I recognize totally different tech but offering ways to get some value back.

mdip 4y ago

> 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". The interesting thing here is that every part of what you said I completely agree with. My behavior, however, indicates otherwise. I didn't read the article[0]. I went directly to the HN comments mostly because I wanted to cut through the hype. 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".

moloch-hai 4y ago
The key is that it is not a breakthrough at all. Breakthroughs have consequences, and this will have none. Soon they will claim "Q>5", "Q>10", etc. all equally inconsequential.

icare_1er 4y ago

HN is generally more excited in a minor release of well-known libraries or of GNOME, than in medical, space, or biology breakthroughs.

upsidesinclude 4y ago

Here's the thing: 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

Unklejoe 4y ago
> BUT ALSO shot out of an "injector" to fall precisely into alignment with the lasers, in vacuum within a plasma field... 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.
- PaulHoule 4y ago
  The tin is reaching 400,000 K, a fusion reactor has to attain more like 100,000,000 K.
zbobet2012 4y ago
All of the problems you just described are solved for in EUV lightsources for lithography on chips at 100khz or more. These are less hard then you make them sound. https://www.youtube.com/watch?v=5Ge2RcvDlgw 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?

PaulHoule 4y ago

I get disappointed that I can't get interest in stories like https://www.world-nuclear-news.org/Articles/First-Light-teams-up-with-CNL-on-tritium-productio 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/TSS2_TLinden_ConstructingAFarnsworth-hirschFusorForNeutronGeneration.pdf 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.

AtNightWeCode 4y ago

Fusion energy is a holy grail in the field of nuclear power. The claims though out the years have been ridiculous. I think it is just natural that people are skeptical.