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.
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:
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.
>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.
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.
Before ignition, very little science had been explored in the "burning plasma" regime. Now that ignition had been figured out, an entire new field of experimentation has been opened up.
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.
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.
here's a video that shows a machine at Berkeley lab that makes a high-performance magnet wire, not sure if it's related to this project but still pretty interesting to see how complex just the wire is- https://www.youtube.com/watch?v=FmmNRaKpBTI&t=2138s
Ironically vacuum, unless super perfect, is not that good insulator. All hvac techs who started compressor on vacuum (albeit much less perfect) can tell :)
> 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.
>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.
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.
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
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.
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?
> 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.
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.
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.
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.
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.
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.
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.
1. The same research that brought us the atomic bomb brought us so much more. Who cares about the motivation of the research? This is such a bad take considering the history of technology evolving out of military development.
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.
I've read some very well informed critiques on HN. The general sentiment will always be super negative absent an easy topic or a clickbait headline which over simplifies a problem to tap into a commonly held feeling.
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.
> 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.
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.
> 1. It is, purely, bomb research dressed up as civilian activity for funding purposes. Everyone working on it has top-secret clearance.
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]
7. It doesn't matter, even if renewables were free. They is no way to store energy from intermittent sources that will allow to power human civilization. You are going to end up like Germany, replacing nuclear power with coal and gas.
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
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.
"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.
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.
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.
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.
> 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".
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.
After a few more major breakthroughs we'll be where fission was in 1942 after Fermi made the first man made neutron chain reaction. After that, we can see what a practical electricity producing plant looks like, and see how much people actually care about small amounts of tritium radiation.
At the moment fuel costs in fission are like 5-10% of total costs for a fission fleet. In fusion it could be lower, but that will not be any means mean the overall system will be cheaper.
We'll have to see the cost tradeoffs: fusion makes much less radioactive material per kWh than fission (but it still makes some) vs. simplicity. Fission is relatively trivial: just put special rocks in a grid and pump water over them as they pour out their star energy.
Progress is good and exciting, but I don't see any reason to think this will have major implications for energy systems anytime soon. Would be happy to be wrong though.
Disclaimer: I switched from studying fusion energy to advanced fission 16 years ago.
Personally I think fission power's failure is a political and marketing one. I don't agree that the waste disposal issues, or the safety issues, are quite the big deal people make of them. (Not saying there are no unsolved issues, just that the issues that exist are not significantly worse than those present burning fossil fuels, and are better in some dimensions. They're just different, and in some ways very emotionally so.)
I think it might be fine that fusion power may be more expensive in some ways than fission, as long as its reputation is kept clean (figuratively and literally). Market fusion power as the savior of humanity, and get enough people to believe it, and it'll be fine.
> Personally I think fission power's failure is a political and marketing one.
I think it's because of the occasional catastrophic failures that spatter our short history with the technology. Fukushima made headline news around the world, leaked large amounts of caesium-137 into the ocean, caused a 20km evacuation radius, is projected to take a total of 30-40 years to clean up, and people think of it as not that bad of a nuclear incident.
In comparison burning fossil fuels is a classic tragedy of the commons problem. Way less sensational. You can do math and say nuclear has a safer track record than coal/oil. You can point to design, engineering or management faults with historical failures. It doesn't change the fact that nuclear had a very fair chance at being the future and shown itself to not be trustworthy. If humanity was a little more perfect maybe we could have pulled it off
I think fissions failure is a inability to plan for complete failure scenarios, were society folds in on itself, suppliers are no longer available or power plants are actually fought over. So the inability is not to get the tech going, but to plan for how it can it be usefull in a unravelling world.
Already economic downturns corelate with fission problems, as plants are not properly maintained. We have one blowing up every thirty years atm. Our reach exceeds our grasp, and there is no shame in admitting to that.
> Personally I think fission power's failure is a political and marketing one
Probably the fact that it's literally the same thing that killed 140 thousands people in an instant and imposed the spectre of a nuclear winter upon us all, had its importance.
Fuel is hardly the only advantage, the major issue with fission is the enormous costs of trying to avoid problems or cleanup after them. Thus 24/7 security, redundancy on top of redundancy, walls thick enough to stop aircraft etc. Fission is still by far the most expensive power source even with massive subsides and is only even close to economically viable as base load power backed up with peaking power plants.
In theory much of that is excessive but there is a long history of very expensive mistakes with massive cleanup efforts. The US talks about three mile island as the largest nuclear accident ignoring the Stationary Low-Power Reactor Number One that killed 3 people. All that complexity and expense comes from trying to avoid real mistakes that actually happened.
LCOE of nuclear is cheaper than almost all other possibilities we have. sure nuclear is very expensive up front, but a nuclear powerplant can run for 100 years while wind and solar had to be completely replaced every 25 years.
your correct that nuclear has had some very expensive accidents, but the chance of a modern gen3+ plant that we'd build today causing any accidents like that in a western country is so very close to 0 that it's not even worth discussing.
Fusion will also have to go to enormous efforts to avoid problems -- not because of public safety, but because it's very difficult to repair anything in the reactor if it breaks. This was a lesson of Three Mile Island: a nuclear accident that doesn't kill anyone is still ruinous for a utility, since their large investment is destroyed.
Came here for the F.U.D and you did not disappoint.
>. Fission is still by far the most expensive power source even with massive subsides and is only even close to economically viable as base load power backed up with peaking power plants.
> the major issue with fission is the enormous costs of trying to avoid problems or cleanup after them. Thus 24/7 security, redundancy on top of redundancy, walls thick enough to stop aircraft etc.
A fusion reactor will also require wall thick enough to stop aircraft. Security will likey be the same to. And there is no fundamental reason why fusion should require any less for any of these.
In fact the actual cost of nuclear is CAPX and comes from the large civil engineering project with high specification, the steam turbine and water towers.
There are lots of fission based reactor designs that have non of these things. So nothing you describe has really much to do with 'fission' itself. Fission plants can also be made so that airborn radiation is practically impossible.
We simply stopped fundamentally advancing fission reactors in the early 70s and instead of solving problems fundamentally, we added lots of regulation.
It's still decades off but as I understand it, this was the hardest nut to crack. They got what, 2.5 megajoules out of 2.1 in?
I might be in the opposite camp as you but this is very much a "where were you when—" moment for me. I'm sure someone will pop in to disappoint me but I think the point is it's no longer a hypothetical exercise.
Of laser energy into a tiny control volume that doesn't consider how much energy went into the laser systems. If you draw the control volume around the building and see that the lasers require vastly more energy than what came out, I think you'll be less excited, right?
We've been getting lots of energy out of fusion since the early 1950s with thermonuclear bombs. We know we can get energy out of a control volume. But is it a practical energy source is still the question imho.
Not an engineer in this field, so I may have misread/misunderstood, but I read that 2.5MJ out for 2.1MJ of laser energy in, NOT the total energy needed to make the whole thing work.. So, in a layman’s world, it is not a net gain of power, only a small subset of the system yielding more power than it took in.
Happy to be proven wrong and told that it is more of a breakthrough than I think it is..
I'm not super excited about current SMR projects either, sadly. The economies of scale that they explicitly turn away from are very real. The economies of mass production that they rely on can't be achieved unless a lot of people are willing to buy the first N for high cost. But who will buy after the first few boondoggle a bit?
I am excited about standardized large light-water reactors at the moment, like the US/Japanese ABWR or Korean's APR-1400 designs. I wish there was more hype around them rather than SMRs and advanced reactors.
My favorite idea in nuclear to rapidly deeply decarbonize is to use a shipyard to mass-product large floating reactors. This gives you economies of scale and economies of mass production. Amazingly, this was seriously attempted in the 1970 and 80s in Jacksonville, Fl on Blount Island, where Offshore Power Systems installed the world's largest gantry crane and got an honest-to-goodness manufacturing license from the Nuclear Regulatory Commission to build 8 of these. [1]
Sadly, my concern above with SMRs happened to OPS and they couldn't break through. Such a good idea though.
Much of fissions complexity comes from safety/damage management. Even after years of advancements we hear about some incidents and radioactive leaks every other decade.
Fusion is a much safer alternative both in incidents and fallout
Is it? Well I guess it is because we don't have a working fusion power reactor yet so the likelihood of an accident is zero. However, if we did have a fusion reactor it would be producing a lot more radioactive waste than a fission reactor.
I definitely wouldn't want to make any broad sweeping statements about something that hasn't been built yet.
> At the moment fuel costs in fission are like 5-10% of total costs for a fission fleet.
Yeah and with a breeder fission reactor we could reduce this to below 1% probably. With a thorium breeder the fuel cost might be essentially 0%. In the vision of Alvin Weinberg you literally just drop some thorium into the fuel salt every once in a while.
But the real issue for nuclear energy is currently capital cost and time not fuel cost. And capital cost can go down massively with GenIV reactors as well.
So I don't see how fusion will be cheaper.
> In fusion it could be lower
But eventually you have to start breeding tritium, so wouldn't that make it more expensive.
> Disclaimer: I switched from studying fusion energy to advanced fission 16 years ago.
Awesome, we desperately need GenIV reactors (even if I dislike that term).
Right. But slapping boiling water around the burning plasma is kind of a rube goldberg usually. See LLNL's LIFE design for example [1]. Things like molten salt walls circulating through a steam turbine and all that.
There are other ideas too, but it's hard to beat a Rankine cycle.
I think we just haven't found the right fusion design.
If we use a reaction that primarily produces beta radiation or other high energy charged particle, sending it through a coil of wire would induce a voltage that we could extract as electric energy.
For that matter, appropriately located coils could be used to extract thermal energy from the plasma directly. The trick there is that we can't get much with the current tokamak and stellarator designs -- the thermal energy is too disordered to use a large coil and the plasma flow is not sufficiently confined to use small coils. There are almost certainly better configurations, but the electrohydrodynamics simulations are tricky. If we keep at it I'm sure we can find a stable configuration with fewer degrees of freedom.
I'm surprised too. I've looked into this before, and it's absolutely right - just not intuitive to me.
We do have radio-photo-voltaic devices, but they're so inefficient it's laughable. And we have RTG generators, which are only practical in limited situations, and again have a very low efficiency.
Well, there is hydro, wind and photovoltaic. And in the fusion field there are startups working on aneutronic fusion, which can generate power directly from charged particles. LPPFusion is one that seemed promising a few years ago, but unfortunately less so now.
This is great! Why is this great? It is great because between magnetic confinement and inertial confinement approaches to fusion generation it is the FIRST one to demonstrate energy gain.
If you are programmer, think of it like your program compiled successfully for the first time. It means that all of the bits between you designing the program, the program being compiled, and the operating system recognizing it as a program, all did what they were supposed to. Of course your program probably doesn't do what you want it to yet, but you have validated a huge chunk of the "pipeline" between what you are trying to do, and doing it with the equipment you have. That is what this is, "hello world" for Fusion Physicists.
And the reason they are so pumped is that they have literally been told for DECADES that why they proposed to do "wasn't possible" (and by that I mean creating actual fusion through inertial confinement.)
Steps 2 - n look a LOT more like engineering steps than "can this even work" steps, okay?
The efficiency of the lasers is awful though and they will have to get at least 100x that energy yield for it to be a net power source. A lot of heat winds up in the laser glass and it takes it a long time to cool between shots so you are doing very good to make a few shots a day. A real power plant is going to need more like 10 shots per second.
Heavy-ion fusion has been talked about since the 1970s and it seems much more practical than lasers for energy production because the efficiency of particle accelerators is pretty good (maybe 30% or more) but it takes a very big machine, the size of a full powerplant, to do do meaningful development. Something like that seems to need about 100 beamlines because otherwise space charge effects prevent you from getting the needed luminosity. Given that you are going to need to protect the wall of the reactor and the beamlines from the blasts and also have a lot of liquid lithium flowing around to absorb neutrons and breed tritium it is hard for me to picture the beam quality being good enough.
There hasn't been much work on it since then. If I had $48 billion to spend I'd think a heavy ion fusion lab would be better than some other things I could buy.
It's not worthless research (not that you said it was), as it still validates various aspects of fusion energy and some of the engineering around it. And it's always been ahead of magnetic containment devices because they only have to keep the conditions for nanoseconds.
But NIF was never, and is not, designed to be a generating reactor, or even a prototype of a testbed. It's a weapons physics facility that happens to do some energy generating research sometimes.
That aside, hitting Q=1 (and be able to use the device again) in any way at all using any equipment is a major milestone that proves humans can get there. From that point, in theory, it's just engineering.
Yeah, either heavy-ion beams or electrically-pumped excimer lasers seems like the path forward for the driver. Higher efficiency, higher repetition rate, possibly more robust. They also need to do away with holraums and switch to direct drive, to reduce target cost, ease alignment issues, and increase energy efficiency.
I don't hold out much hope for a practical, economical reactor from inertial confinement, but it's certainly exciting to see them achieve ignition & scientific breakeven, even if it's 10 years behind schedule. The one nice thing about ICF is that the energy gain shoots up dramatically once you cross the ignition threshold. That means they're arguably closer than tokamaks, even though both concepts need ~100x the demonstrated gain to get from where they are now to a workable reactor. (Ie, tokamaks have hit Q~0.3, need to get Q~30, vs ICF that has hit Q~1, needs Q~100).
Unfortunately large fusion is unlikely to ever be economic because the cost of solar/battery is coming down so quickly and is already in the 1-2 cents per kilowatt hour for the solar component. And costs will continue to drop.
Small scale fusion on the other hand would have a viable niche application at the poles, in the sea or underground or any other environment that is without sun or space.
We won't know what the cost of solar/battery will be in a sustainable energy economy, until someone builds a solar-powered solar panel and battery factory. At the moment, productions costs are heavily (as in, entirely) subsidised by fossil fuels (mostly coal).
I'd be very interested to see the breakdown of input energy costs. Most notable is the raw energy cost required to power the lasers and control machinery in the experiment. But then there are other costs, all of which must be amortized over time for any real-world use case to exist. I say this because the journalists in this piece imply that net gain is simply based off of the amount of energy pumped into the experiment while it operated, but the total input energy would clearly be more than that.
On the extreme end, there's the energy cost of building the machine and engineering its components. For the vast majority of these, we can probably all agree that were a fusion power plant to be built, the net gain would fully eclipse these initial inputs fairly quickly. This may sound silly, but remember that the economic context where fusion so often sits is one that centers on renewable energy and sustainability. These costs do have to be accounted for.
On the other end, there's the energy cost consumables. For example, the deuterium and tritium fuel input into the device, which need to be purified (deuterium from water, possibly tritium from the atmosphere) or otherwise isolated (from what I understand, tritium is a byproduct from fission reactors and they serve as its primary source in scientific applications). It may well be that the energy cost of acquiring these consumables is fractions to fractions of a fraction of the energy cost of running the device, effectively constituting a rounding error. But I think when we're talking about net gain, a clear definition and accounting of the input energy required to run the experiment would be useful to communicate to the public.
I hope we see disclosure of these details with all the expected caveats when the peer-reviewed article goes to print and journalists have another feeding frenzy.
Early reports are are not good. For every joule delivered to the chamber, it takes 100 joules of electrical power. Heat to electricity is 50% efficient at best. Reports are that with 2.1mj of input, they generated 2.5 mj of output. Taking inputs and electrical production into account, this means 0.6% is all they are getting out vs. what they put in.
These over-unity reports are meaningless, because every damn one of them only measures Q-plasma, not Q-total.
NIF people like to call this the “target gain”, but someone there has been whispering “net gain” to the journalists, in their ongoing campaign of deliberately deceptive hype. But “target gain” isn’t even (pellet output)/(laser output). The denominator is laser energy deposited in the hohlraum; the rest of it doesn’t count. And this deposited laser energy is estimated based on a model of laser deposition—it’s not measured. (At least, this is the way it was the last time I bothered reading a paper from NIF. I got bored with it a while ago.) The modeling codes are classified; no one without a need to know gets to examine them, and they are not well benchmarked. So the actual target gain is likely < 1 in any case.
I have personally taken a tour of the NIF at Livermore. The guide was an old hand, who constantly remarked about the efforts of NIF towards "stockpile stewardship," ie the maintenance of the US arsenal of nuclear weapons. It seemed like NIF was all about the stockpile stewardship first, and fusion research was a secondary consideration.
The capability of the NIF to get positive energy from the energy that they impart on the Hohlraum itself is neat, but I constantly discount any milestones that Livermore/NIF report, because the inertial confinement approach has such higher barriers to commercialization than tokamak style approaches, that I just consign it to "boondoggle" in my head.
Yeah, the lasers could be 20x more efficient, and yeah, they probably could figure out how to pump 10s of targets into the chamber per second, but the energy extraction is just completely missing from the considerations. The engineering challenges are a whole 'nother level for NIF, a big barrier to usability.
Seems like energy extraction would be similar to other D-T designs: surround the reaction chamber with molten FLiBe or lead-lithium and run some coolant pipes through it.
> surround the reaction chamber with molten FLiBe or lead-lithium
So manufacturing fusion reactors would use a lot of lithium, which is already in short supply. That would be an interesting complication with the demand of lithium for electric vehicle batteries. Maybe the Li supply situation will be eased by then.
Personally my money is on SPARC as a demo plant and its planned successor ARC as a commercial power plant prototype. Unlike ITER these systems use high field strength superconducting magnets, which directly translates to a much smaller machine for the same energy gain. Because of the smaller machine size, it can be built much faster than ITER. The company building SPARC plans to achieve first fusion around the same time as ITER, and since their machines are smaller, they should be able to move faster. That said ITER will be fantastically useful for proving a lot of science, and I am happy we have so many viable fusion projects in the works.
I'm a complete layman when it comes to ICF, but I'm assuming that there is a scaling factor between surface area and volume that would eventually help here? As in, the lasers initiate fusion on the surface of the fuel pellet, which propagates the fusion into the interior of the pellet in a chain reaction / positive feedback kind of way. So that if you increased the surface area of the pellet by a factor of 10, you'd get 100 times more total output energy (since there is 100 times more mass in a pellet with 10 times the surface area). So you'd need 10 times the current input power, but would get 100 times the output power.
That won’t work, I don’t think. You can’t make the pellets much larger because laser nonuniformities and hydrodynamic instabilities will kill the implosion; there will be no fusion at all. But that’s not a problem, you see, because in a commercial reactor you’ll have a pellet factory making the required one million targets per day, and they will be injected into the chamber 10 times per second, with practically no down time. And each shot will have gain > 100 to get net energy out.
Readit News
US Department of Energy: Fusion Ignition Achieved - https://news.ycombinator.com/item?id=33971377
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.
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.
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")
https://www.youtube.com/watch?v=9qqEU1Q-gYE
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.
You mean, starting from the journalists writing the articles?
I have no experience in fusion, so can't comment on that either way.
Deleted Comment
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?
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.
along with 1.3 million others [0]. just sayin'
[0] https://news.clearancejobs.com/2022/08/16/how-many-people-ha...
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.
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.
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
[3]: https://doi.org/10.1016%2Fj.fusengdes.2011.11.005
[4]: https://doi.org/10.1016/j.fusengdes.2013.05.043
Dead Comment
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.
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.
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.
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/
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".
Dead Comment
At the moment fuel costs in fission are like 5-10% of total costs for a fission fleet. In fusion it could be lower, but that will not be any means mean the overall system will be cheaper.
We'll have to see the cost tradeoffs: fusion makes much less radioactive material per kWh than fission (but it still makes some) vs. simplicity. Fission is relatively trivial: just put special rocks in a grid and pump water over them as they pour out their star energy.
Progress is good and exciting, but I don't see any reason to think this will have major implications for energy systems anytime soon. Would be happy to be wrong though.
Disclaimer: I switched from studying fusion energy to advanced fission 16 years ago.
I think it might be fine that fusion power may be more expensive in some ways than fission, as long as its reputation is kept clean (figuratively and literally). Market fusion power as the savior of humanity, and get enough people to believe it, and it'll be fine.
I think it's because of the occasional catastrophic failures that spatter our short history with the technology. Fukushima made headline news around the world, leaked large amounts of caesium-137 into the ocean, caused a 20km evacuation radius, is projected to take a total of 30-40 years to clean up, and people think of it as not that bad of a nuclear incident.
In comparison burning fossil fuels is a classic tragedy of the commons problem. Way less sensational. You can do math and say nuclear has a safer track record than coal/oil. You can point to design, engineering or management faults with historical failures. It doesn't change the fact that nuclear had a very fair chance at being the future and shown itself to not be trustworthy. If humanity was a little more perfect maybe we could have pulled it off
Already economic downturns corelate with fission problems, as plants are not properly maintained. We have one blowing up every thirty years atm. Our reach exceeds our grasp, and there is no shame in admitting to that.
Probably the fact that it's literally the same thing that killed 140 thousands people in an instant and imposed the spectre of a nuclear winter upon us all, had its importance.
In theory much of that is excessive but there is a long history of very expensive mistakes with massive cleanup efforts. The US talks about three mile island as the largest nuclear accident ignoring the Stationary Low-Power Reactor Number One that killed 3 people. All that complexity and expense comes from trying to avoid real mistakes that actually happened.
https://www.iea.org/reports/projected-costs-of-generating-el...
LCOE of nuclear is cheaper than almost all other possibilities we have. sure nuclear is very expensive up front, but a nuclear powerplant can run for 100 years while wind and solar had to be completely replaced every 25 years.
your correct that nuclear has had some very expensive accidents, but the chance of a modern gen3+ plant that we'd build today causing any accidents like that in a western country is so very close to 0 that it's not even worth discussing.
>. Fission is still by far the most expensive power source even with massive subsides and is only even close to economically viable as base load power backed up with peaking power plants.
https://www.statista.com/statistics/748580/electricity-cost-...
Seems Solar is the most expensive, and by a large margin?
It looks like nuclear is cheaper vs almost all "renewables"?
There is a nuclear power plant ~10KM from me that set world records:
- On October 7, 1994, Pickering Unit 7 set the world record for continuous runtime at 894 days, a record that stood for 22 years.
Can you provide the number of days that "WIND" or "Solar" have provided continuous power for?
That complexity and expense is because you are building machines which can run for 894 days NON-STOP. (CANDU plants can be refuelled while operating)
Diesel locomotives are expensive, a lot of this is attributed to the engine designed to run at high-output for an extended amount of time.
A fusion reactor will also require wall thick enough to stop aircraft. Security will likey be the same to. And there is no fundamental reason why fusion should require any less for any of these.
In fact the actual cost of nuclear is CAPX and comes from the large civil engineering project with high specification, the steam turbine and water towers.
There are lots of fission based reactor designs that have non of these things. So nothing you describe has really much to do with 'fission' itself. Fission plants can also be made so that airborn radiation is practically impossible.
We simply stopped fundamentally advancing fission reactors in the early 70s and instead of solving problems fundamentally, we added lots of regulation.
Seems like power generation still counts on externalities being external.
I might be in the opposite camp as you but this is very much a "where were you when—" moment for me. I'm sure someone will pop in to disappoint me but I think the point is it's no longer a hypothetical exercise.
Of laser energy into a tiny control volume that doesn't consider how much energy went into the laser systems. If you draw the control volume around the building and see that the lasers require vastly more energy than what came out, I think you'll be less excited, right?
We've been getting lots of energy out of fusion since the early 1950s with thermonuclear bombs. We know we can get energy out of a control volume. But is it a practical energy source is still the question imho.
Happy to be proven wrong and told that it is more of a breakthrough than I think it is..
It's always the same…
I am excited about standardized large light-water reactors at the moment, like the US/Japanese ABWR or Korean's APR-1400 designs. I wish there was more hype around them rather than SMRs and advanced reactors.
My favorite idea in nuclear to rapidly deeply decarbonize is to use a shipyard to mass-product large floating reactors. This gives you economies of scale and economies of mass production. Amazingly, this was seriously attempted in the 1970 and 80s in Jacksonville, Fl on Blount Island, where Offshore Power Systems installed the world's largest gantry crane and got an honest-to-goodness manufacturing license from the Nuclear Regulatory Commission to build 8 of these. [1]
Sadly, my concern above with SMRs happened to OPS and they couldn't break through. Such a good idea though.
[1] https://whatisnuclear.com/offshore-nuclear-plants.html
Because some countries consider even 500MW reactors SMR if they are GenIV.
SMR has become kind of widely used for lots of different things.
Fusion is a much safer alternative both in incidents and fallout
I definitely wouldn't want to make any broad sweeping statements about something that hasn't been built yet.
Yeah and with a breeder fission reactor we could reduce this to below 1% probably. With a thorium breeder the fuel cost might be essentially 0%. In the vision of Alvin Weinberg you literally just drop some thorium into the fuel salt every once in a while.
But the real issue for nuclear energy is currently capital cost and time not fuel cost. And capital cost can go down massively with GenIV reactors as well.
So I don't see how fusion will be cheaper.
> In fusion it could be lower
But eventually you have to start breeding tritium, so wouldn't that make it more expensive.
> Disclaimer: I switched from studying fusion energy to advanced fission 16 years ago.
Awesome, we desperately need GenIV reactors (even if I dislike that term).
I'm pretty sure I saw that in a 'goop' sales pitch.
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I guess we still don't have anything better than boiling water, right?
There are other ideas too, but it's hard to beat a Rankine cycle.
[1] https://en.wikipedia.org/wiki/Laser_Inertial_Fusion_Energy
If we use a reaction that primarily produces beta radiation or other high energy charged particle, sending it through a coil of wire would induce a voltage that we could extract as electric energy.
For that matter, appropriately located coils could be used to extract thermal energy from the plasma directly. The trick there is that we can't get much with the current tokamak and stellarator designs -- the thermal energy is too disordered to use a large coil and the plasma flow is not sufficiently confined to use small coils. There are almost certainly better configurations, but the electrohydrodynamics simulations are tricky. If we keep at it I'm sure we can find a stable configuration with fewer degrees of freedom.
We do have radio-photo-voltaic devices, but they're so inefficient it's laughable. And we have RTG generators, which are only practical in limited situations, and again have a very low efficiency.
So hot water it is!!
If you are programmer, think of it like your program compiled successfully for the first time. It means that all of the bits between you designing the program, the program being compiled, and the operating system recognizing it as a program, all did what they were supposed to. Of course your program probably doesn't do what you want it to yet, but you have validated a huge chunk of the "pipeline" between what you are trying to do, and doing it with the equipment you have. That is what this is, "hello world" for Fusion Physicists.
And the reason they are so pumped is that they have literally been told for DECADES that why they proposed to do "wasn't possible" (and by that I mean creating actual fusion through inertial confinement.)
Steps 2 - n look a LOT more like engineering steps than "can this even work" steps, okay?
Scaling up Qplasma from 1 to ~1000, and scaling up operating time from a microsecond to a megasecond are just two of them.
I have a feeling there is still some science to do.
Heavy-ion fusion has been talked about since the 1970s and it seems much more practical than lasers for energy production because the efficiency of particle accelerators is pretty good (maybe 30% or more) but it takes a very big machine, the size of a full powerplant, to do do meaningful development. Something like that seems to need about 100 beamlines because otherwise space charge effects prevent you from getting the needed luminosity. Given that you are going to need to protect the wall of the reactor and the beamlines from the blasts and also have a lot of liquid lithium flowing around to absorb neutrons and breed tritium it is hard for me to picture the beam quality being good enough.
There hasn't been much work on it since then. If I had $48 billion to spend I'd think a heavy ion fusion lab would be better than some other things I could buy.
But NIF was never, and is not, designed to be a generating reactor, or even a prototype of a testbed. It's a weapons physics facility that happens to do some energy generating research sometimes.
That aside, hitting Q=1 (and be able to use the device again) in any way at all using any equipment is a major milestone that proves humans can get there. From that point, in theory, it's just engineering.
I don't hold out much hope for a practical, economical reactor from inertial confinement, but it's certainly exciting to see them achieve ignition & scientific breakeven, even if it's 10 years behind schedule. The one nice thing about ICF is that the energy gain shoots up dramatically once you cross the ignition threshold. That means they're arguably closer than tokamaks, even though both concepts need ~100x the demonstrated gain to get from where they are now to a workable reactor. (Ie, tokamaks have hit Q~0.3, need to get Q~30, vs ICF that has hit Q~1, needs Q~100).
Small scale fusion on the other hand would have a viable niche application at the poles, in the sea or underground or any other environment that is without sun or space.
And they have to use traditional energy sources, or buy energy from neighbors.
On the extreme end, there's the energy cost of building the machine and engineering its components. For the vast majority of these, we can probably all agree that were a fusion power plant to be built, the net gain would fully eclipse these initial inputs fairly quickly. This may sound silly, but remember that the economic context where fusion so often sits is one that centers on renewable energy and sustainability. These costs do have to be accounted for.
On the other end, there's the energy cost consumables. For example, the deuterium and tritium fuel input into the device, which need to be purified (deuterium from water, possibly tritium from the atmosphere) or otherwise isolated (from what I understand, tritium is a byproduct from fission reactors and they serve as its primary source in scientific applications). It may well be that the energy cost of acquiring these consumables is fractions to fractions of a fraction of the energy cost of running the device, effectively constituting a rounding error. But I think when we're talking about net gain, a clear definition and accounting of the input energy required to run the experiment would be useful to communicate to the public.
I hope we see disclosure of these details with all the expected caveats when the peer-reviewed article goes to print and journalists have another feeding frenzy.
These over-unity reports are meaningless, because every damn one of them only measures Q-plasma, not Q-total.
The capability of the NIF to get positive energy from the energy that they impart on the Hohlraum itself is neat, but I constantly discount any milestones that Livermore/NIF report, because the inertial confinement approach has such higher barriers to commercialization than tokamak style approaches, that I just consign it to "boondoggle" in my head.
Yeah, the lasers could be 20x more efficient, and yeah, they probably could figure out how to pump 10s of targets into the chamber per second, but the energy extraction is just completely missing from the considerations. The engineering challenges are a whole 'nother level for NIF, a big barrier to usability.
So manufacturing fusion reactors would use a lot of lithium, which is already in short supply. That would be an interesting complication with the demand of lithium for electric vehicle batteries. Maybe the Li supply situation will be eased by then.
https://cfs.energy/news-and-media/new-scientific-papers-pred...