Fusion News Ignites Optimism
nature.comI like being optimistic, but there is nothing to be optimistic about when it comes to producing electrical power from laser ICF. It's a weapons program.
Also, I spent a few years as an engineer at a stellarator. This video[0] recently came out and I find it's the best crash course on the nuances of reactor design that I've seen. It really nails the thoughts and feelings of fusion researchers. It was especially refreshing to hear in public that ECRH is the only viable heating method for a reactor.
If you watch this you might think I'm pessimistic about fusion, but I'm not. Fusion has been sold as this secret Ace up our sleeve that will come in and decarbonize our grid in a matter of decades. It isn't that. That's what's been sold because it's difficult to justify the field when the timelines don't decarbonize the grid in 50 years. The important thing to know is that the world doesn't end in 50 years. Energy demands are ever increasing and the supply is ever diminishing. Fusion science is expensive and time consuming. Humans will have to do the work if they want to stay on the current track beyond the next 100 years. It might seem like a subtle point and a doomed one to make considering how shortsighted we as a society have demonstrated to be.
While I'm excited for this, I'm also cynical about the public reaction to fusion power as it gets closer to success and eventual general availability.
These past 2 years have highlighted to many how a combination of poor critical thinking and politicisation of so many aspects of our lives can lead to literal catastrophes.
Will the public see Fusion as the wonderful advancement for humanity that it will likely be, or will they see it as another dangerous nuclear thing? Will they see it as taking jobs from hard-working coal/oil workers? Will it be spun as the green energy sector not making their minds up and flip flopping between solar/wind/fusion/etc? Will there be stories about how we could accidentally create a black hole and destroy the world?
Hopefully I'm just being cynical, but I am worried about how the general public will perceive it, and/or how it will be sold by politicians and the less reputable parts of the media.
Use of fusion as an energy source removes a lot of threats our civilizations are facing but it also comes with some caveats rooted in human behavior.
Human energy consumption has always gone up when the supply got more efficient, from coal to oil to fission. While here, the power generation itself won't have such a drastic impact (unless humanity overdoes it, though, we seem to always do that) but maybe more power means more consumption and demand for other goods that get used up while using things that consume power. And with enough power you can think about making things that consume more or even build more things that consume more power. Lots of processes that were considered too wasteful suddenly become feasible.
Just like with digital documents, when people predicted that paper wouldn't be needed in the modern economy and the demand for paper would decline, it has actually skyrocketed - because a paper document isn't important anymore. You throw it away and print a new one when it has a crease.
Historically, we've been very bad at predicting such side effects. So I won't buy in a 'fusion solves everything' mindset. Fusion power can be a boon for humanity on a global scale but it could also make some problems worse.
Your first point is not supported by the data. The US Energy Information Agency keeps track of this[1], and the per capita energy use peaked around 2000.
And we are much better at running an energy-efficient economy: energy use/real $ GDP has halved in the last century.
The trend may not continue. People might start to do much more air travel (which would require massive runway building). Global warming might increase the need for AC. But my intuition is that there is some limit to the amount of energy one person can consume.
[1] https://www.eia.gov/totalenergy/data/annual/pdf/sec1_13.pdf
It is good to see that the per capita trend has reversed, maybe if the global population would not increase steadily we may actually not increase energy consumption steadily.
Edit: I found an interesting nature article[0] that looks at different correlations of population and consumption to identify if there is an anthropocene epoch. There are pretty clear-cut trends but who knows, maybe Earth's population will actually reach a kind of steady state.
Global population is expected to plateau soonish.
> the per capita energy use peaked around 2000.
1980, actually.
Yeah, capital-E Energy is mostly for capital-W Work and thermodynamics. Once you refrigerate your living space and don't walk anywhere and everything you want is brought to your door what else are you going to do?
I’m not sure whether you’re serious, but:
Bigger cars? Supersonic city trips to the other side of the world? Weekends in Antarctica? A week in one of SpaceX’s hotels? High-resolution screens on every wall of your home, plus the AC needed to keep your house cool? Reshape a mountain to improve your view? Transform lead into gold? Mine bitcoin?
If energy were free, I foresee accelerated destruction of nature. At best, the world would become a gigantic park.
> If energy were free, I foresee accelerated destruction of nature.
Perhaps the reverse, eventually. If costs of space travel dropped enough, we could push polluting industry out into orbit and further, and start repairing Earth. It's impossible now, but if there were little difference on the margin for the businesses between working on the surface and upwell, then businesses would hesitantly say "ah, what the hell, we'll do our stuff up there, you go ahead with your silly environmental programs if that floats your boat". Social progress happens when the market stops caring about it, and doesn't resist it anymore.
In a world where energy is free, I don’t see polluting industry as a problem. What pollution is there that can’t be prevented if you can spend as much energy as you want in recycling stuff? If you try hard enough, about everything can be taken apart into its chemical elements.
The problem would be the demand for resources. Yes, there’s the asteroid belt, but it is far away. Would we get there before we would have dug up the earth? Maybe.
The market is very much an engine for social progress. See eg https://www.econlib.org/jim-crow-more-racist-than-the-railro...
> Jim Crow laws established apartheid, that is, legally enforced segregation. Railroad companies provide an interesting historical example of business incentives. These private companies were often willing, against the political correctness of the times, to sell tickets to both blacks and whites and to not segregate their customers in different cars or compartments. Poor whites and poor blacks purchased second-class tickets, while rich whites and occasionally rich blacks rode in first-class cars. The situation was far from perfect, and violence sometimes erupted, but it was better than the segregationist state-enforced laws that followed.
> A historian of populism observes:
>> More than any other institution, train cars and railroad stations exemplified the modern dilemma of the racial order. They were places where mobile, unsupervised, anonymous travelers met in close quarters. Making the situation more explosive, those whites, including most farmers, who could not afford a first-class ticket met blacks on equal terms. In contrast to the workplace where blacks served white employers, or in the supply store where blacks owed debts to white merchants, in a railroad car blacks and whites paid the same fare for the same right to a seat. Accordingly, whites made the railroads a primary target of the new segregation laws. Reform-minded southerners considered these laws a mark of modern and progressive race relations. (Charles Postel, The Populist Vision, Oxford University Press, 2007, p. 178)
But, didn't the market trade the same people as property? How is the market an engine for social progress there? Isn't that a bit cherry picked?
Well, basically the 'market' is just people trading. People react to incentives and have preferences.
Luckily, people are hypocrites, so they will say that we should 'buy American', but then happily engage in free trade. Or they say that we should segregate races, but then greed dictates that it's more profitable not to discriminate like that.
Yes, if people are bought and sold, that also happens on a market. Alas.
Apropos that topic, you might like https://pseudoerasmus.com/2014/09/05/antebellum_ussouth_cott...
This is an interesting read as to the possible caveats of fusion power [0]. It's interesting, whether one reaches the same conclusion as the plasma physicist who wrote the article or not.
[0] https://thebulletin.org/2017/04/fusion-reactors-not-what-the...
> Lots of processes that were considered too wasteful suddenly become feasible.
I worry about this, too, but couldn't there be some positive effects here, too? E.g. what if it made desalination a lot cheaper?
Why do you even worry?
Because the secondary effects of something becoming more efficient can be harmful, in counterintuitive ways.
E.g. if some process in steel manufacturing is improved to require less power, you might think, yay, there's less power needed so less CO2 released. Good for mitigating global warming. But what might actually happen instead is that it becomes feasible to make more things out of steel because it is cheaper than before, so more energy is used on steel production in total, even though per unit it is more efficient.
The same thing could happen with fusion energy, but in ways we can barely imagine now. What high-power workloads are not even considered now that would be cheap enough with fusion power?
Yes, I understand that. But if you run your high-power workload with fusion, you won't be releasing any CO2.
Your explanation reminds of the common example that increased car safety leads to more speeding. And somehow arguing that increased safety is futile.
But people like having more steel and like being able to go faster at the same level of safety.
> While here, the power generation itself won't have such a drastic impact (unless humanity overdoes it, though, we seem to always do that) but maybe more power means more consumption and demand for other goods that get used up while using things that consume power.
Eh, we are sitting on a giant ball of matter. Not much worry about using stuff up.
(We might use up any one particular thing. But there are substitutes.)
> another dangerous nuclear thing
I think this really understates the case against nuclear power. The problem with nuclear power stations is they are prone to the same kind of industrial accidents all large plants are prone to, and they are on the more dangerous end of the scale when it comes to what can happen if there is an industrial accident. You can say that people aren't accurately weighing the risks, but you can't say it's irrational for people in, say, Japan, to be very skeptical of their government's capacity to either regulate industry or respond to industrial accidents and spills in a way that protects public health.
Fusion power, as far as I can see, is not on the more dangerous end of the scale, so would probably pass all of the mainstream, basically reasonable objections to new nuclear plants.
(For the record, I'm not anti-nuclear.)
No, the problem with nuclear power stations is they are way too expensive.
Fusion promises to make this main problem worse, not better.
Fusion is a great example of solving the wrong problem.
This is a really good point, and could well be true, although I think it's a bit more complicated.
Fission has two problems: the emotional one – weapons/danger, and the practical one – cost. Yes weapons could be a practical issue, but I think it's more an "emotional" issue.
The question is, is it only the practical reason that is preventing widespread adoption of fission power? On the surface, maybe! Unpacking it a bit, I'm not sure. Anti-nuclear sentiment has caused government policy changes, not the cost issue. Similarly, restricting nuclear power technology to only certain countries is a political issue, not a cost issue, and more closely aligned with the former.
Cost is a big issue, but I do wonder if we'd get over it if the danger aspect disappeared. The long term economics of nuclear power are actually really good, it's just that it takes ~10 years to realise those economics compared to (e.g.) ~3 for natural gas.
Cost has been the problem with fission. The first nuclear buildout in the US ended because of market forces, not because of TMI. Costs were higher than promised, a constant problem then and now. Electricity demand growth slowed, and with the passage of PURPA in 1978 non-utility sources started to be added to the grid. Nuclear could not compete with them even then.
Nuclear's long term prospects are poor, for one big reason: it has never shown good experience effects. This means its cost has not come down with time. Any technology like that is doomed, if it has competitors that are improving. PV started off orders of magnitude more expensive than nuclear (levelized cost of energy) but now is much cheaper, because PV improved 20% for each doubling of cumulative production and nuclear didn't.
> Nuclear's long term prospects are poor, for one big reason: it has never shown good experience effects.
Good point, I hadn't considered this. I would suggest that a possible cause for this is lack of investment though. We had the 1st generation. Most current reactors are gen-2 or gen-3. Gen 4 hasn't really started use, still in R&D I think. There are ideas for Gen 5 but no progress. Each generation seems to bring moderate energy improvements, and significant cost, safety, and waste management improvements, but the interest just isn't there.
I think the problem is not lack of investment, but how nuclear power plants are built. Experience effects come from people doing a task over and over, learning to do it faster and modifying it so it can be done faster and better. But there's little opportunity for that in nuclear construction. Most workers will not work on many NPPs, and the designs are not easily changed.
It might be better if a string of smaller but identical NPPs were built with overlapping construction timelines, so groups of workers could specialize on one part of the construction of each and switch to the next in line to repeat the process. This would be a kind of assembly line without a factory. But this would require construction of many reactors, which means they'd have to be small. Renewables benefit from having huge opportunity for this kind of pipelining, because individual units are so small.
"green energy sector not making their minds up and flip flopping between solar/wind/fusion/etc"
Since fusion does not work sustainable yet (or at all), I would not classify it as green energy. (Where is for example the tritium coming from?)
But once it works - it likely will not magically supply all of humanity at once in a way, that is way cheaper than what we can have with wind, water and sun now.
So why flip flopping? We use what works. If fusion really works soon, awesome.
But honestly, I have to see, to believe. What I see is, that solar and co. are working now and do not require a fundamental breakthrough for very, very complex machinery under heavy fusion fire to work consistently.
And desserts for solarfarming, we have enough. As well, as many, many roofes in the cities. Solarfoils might be the next big thing to cover them big scale cheaply. And stationary batteries can be made of cheap materials avaible in abundance. Lots of other possibilities, too. Simple, reliable tech, compared to Fusion. So fusion would be nice to have, but I would not allocate more critical ressources to it, that might be better spend elsewhere.
Sure, investing into the energy grid, sounds not as sexy and interesting as building a fusion reactor. But maybe that is, what is currently more needed, to make it more flexible for the fluctating renewable energy sources.
And with the sun, we have already a big working fusion reactor. Why not focus on harvesting that energy more?
> (Where is for example the tritium coming from?)
Yeah, I know that. Mostly from nuclear fission reactors. So currently not really sustainable. Or is the plan, to keep the fission reactors running, to fuel the fusion reactors?
You could do that. Or you could probably breed them from excess neutrons in some fusion reactor.
Why do you think fission wouldn't be sustainable? Or do you mean, fusion alone wouldn't be sustainable? I guess that you'd always have some auxiliary industries.
Certainly we'll have all of the above.
> Will it be spun as the green energy sector not making their minds up and flip flopping between solar/wind/fusion/etc?
Well, the green energy sector is big. Solar companies push solar, wind folks push wind, and well, fusion folks are pushing for funding and VC money.
But the important thing is, we need all of them. Plus batteries (and battery-like systems).
And, yes, there will be spin doctors trying to discredit "green" because X, but that's what they do anyway, fusion or not.
> Will there be stories about how we could accidentally create a black hole and destroy the world?
Good idea, maybe :D But we'll sure hear a lot about how much irradiated/activated waste it will produce, and how it's not green at all, and so on.
> But the important thing is, we need all of them.
Why do we need fusion?
Philosophically we don't _need_ anything of course :)
But fusion as a power source: abundant fuel source, cleanest (no emissions, minimal raw materials required, minimal waste to bury), safest (no proliferation risk, safest to install and operate, no need to climb towers), no intermittency problem.
All of those are desirable, but in no sense do any imply the necessity of fusion. They don't even imply the overall desirability of fusion, since one must also weigh the negatives, like cost.
The cost of development is amortized over infinity. (Sure, on the other hand the NPV of a perpetuity bond is finite.)
Of course (economically) the optimal allocation of current resources/funds probably would not involve fusion research, but instead instant (ASAP) replacement of coal, oil, gas power plants. Then working on fusion. But if we look at what fusion researchers should do, either they could be retrained or we can simply go ahead and print some money to pay them to work on what they want to do anyway (fusion research).
> fusion power as it gets closer to success and eventual general availability
IMO it is not clear that fusion will ever be useable for power plants: Depending on costs (construction/maintenance/decomissioning), it might never be competitive with (battery backed) photovoltaics (or wind), no matter how much progress we make.
Personally I believe that fusion research is worthwile no matter the outcome, but calling it a "purely academic waste of ressources without positive environmental/economical ROI" might turn out to be correct (playing devils advocate here but this is important to consider, no matter how much pro-nuclear you are).
A lot of the recent Fusion startups seem to be making worryingly unrealistic claims that make me somewhat skeptical.
Whenever they talk about putting a fusion reactor in a shipping container, or on the back of a truck that's a red flag. Any fusion plant capable of useful power output is going to have to kick out enough neutron radiation to need some pretty serious shielding that just makes that impossible.
Another problem is the way they often pitch the energy gain numbers. Q=1 sounds great, the output energy equals the input energy, but that's only the input energy required to maintain the plasma. The actual energy to power the plant and run the heat exchange system and such as a whole (Engineering Gain = 1) is likely to be about 22x that. Then to be economically viable in practice the gain might need to be an order of magnitude or more again.
> Personally I believe that fusion research is worthwile no matter the outcome, but calling it a "purely academic waste of ressources without positive environmental/economical ROI" might turn out to be correct (playing devils advocate here but this is important to consider, no matter how much pro-nuclear you are).
One thing to remember is that a major goal of fusion research is also weapons applications, those that is never publically admitted.
Not sure I agree with this; I just don't see the weapon applications of fusion power... Also most participants are either already nuclear powers (US, EU, Russia, China, India) or could just build thermonuclear weapons already if they wanted to (Korea, Japan, etc.)
Or maybe you had completely different weapon applications in mind?
No country in the world that doesn't already have them can "just build nuclear weapons if it wanted", international treaties are extremely prohibitive of that. In particular, if Japan wanted to build a nuclear weapon, it would face tremendous opposition from China, while S Korea would face the same from both China and N Korea.
Also, fission weapons tests are currently banned, which also indirectly bans fusion weapons tests, as fusion weapons require a fission step. ICF experiments perfectly mirror conditions inside a fission-fusion bomb though, so are a way of furthering research into improving the yields or other characteristics of such bombs (which have existed since the early 1950s, this is not some far-fetched concept).
> international treaties [...], political opposition
Are just reasons for countries to not want nuclear weapons. But if e.g. Japan announced a nuclear weapon program (or it was uncovered by foreign intelligence) I highly doubt that anyone could/would stop them-- hinder their economy or facilities with sanctions or sabotage, sure, but outright stop them from becoming a nuclear power? Unlikely.
IMO every bigger western-ish nation state has the ressources required to build nuclear weapons; they just lack motivation to do so.
Just consider that smaller states like France were already able to do this in the 1950ies, and relevant helper technologies (computer aided design, simulation, industrial control) are MUCH more accessible and advanced today.
Fusion research, on the other hand, is not going to help with the major challenge in becoming a nuclear power: it does not help with obtaining highly enriched fissile material.
If countries wanted to throw research funds at becoming a nuclear power, it seems infinitely more likely to me that those would go into "innovative reactor research" with the endgoal of producing HEU or plutonium.
I agree with you that there are lower hanging fruit than fusion research for becoming a nuclear power.
I do not agree with you that Japan could in practice successfully acquire nuclear weapons with only economic sanctions to fear. I believe that China would be likely to declare war before allowing Japan to become a nuclear power, and I think it would have significant international support. Of course, that would be many years away, as a last resort if all else failed and their weapons program is nearing fruition. But I do believe it would happen eventually.
Inertial Confinement Fusion is useful for H-Bomb research, and other styles of fusion are probably tangentially useful for understanding high energy physics.
Electricity for high power directed energy weapons. (This is my guess as to why Lockheed’s skunkworks has been working on compact fusion reactors.)
I have never heard of fusion weapons research, or what they would even be. My understanding is limited but where I can see fission leading to weapons, I can't see the same for fusion.
Could you give some more detail? What form would a fusion weapon take? Is it about the laser technology?
The first thermonuclear weapon (or H-bomb) test was successfully completed in 1952. That is, a nuclear bomb that uses a fission reaction to create the conditions for a more pworful fusion reaction, which is either the final step, or is used to power an additional fission step, amplifying the final explosion many times more.
The NIF experiment explained here, which uses a laser to generate X rays by heating the walls of a heavy metal hohlraum, and then uses these X-rays inside the hohlraum to compress a pellet of gas to ignite a fusion reaction is very similar to the conditions inside an H-bomb, which also generates X-rays (via a fission reaction) to compress and ignite a fusion reaction.
The weapons use is relatively simple - fusion reactions expel much more energy than fission reactions, and using the power of a fission reaction to compress and to ignite a fusion reaction inside a large amount of gas expels much more energy than simply exploding the power of the fission reaction outwards.
The NIF and some other facilities (eg the Sandia Lab Z machine) are for studying fusion plasmas in order to understand their behaviour in thermonuclear weapons first, and possible application in power generation as a distant second. That’s pretty explicit, it’s a way of keeping up nuclear weapons research and maintenance without detonating actual devices and breaching test ban treaties and causing various other messes.
JET, ITER, Wendelstein and other magnetic confinement facilities on the other hand are investigating fusion as a source of grid energy.
Thermonuclear bombs are fusion weapons (with a fission trigger).
Having relatively easily handled, high density energy sources would also probably lead to deployment of energy weapons.
Most modern weapon designs are actually fission-fusion-fission designs with most of the energy actually coming from the final fission step - the latter being driven by neutrons from the fusion step. Things get even more complicated with the fact that primaries are fusion boosted fission and the fusion step contains a fission "sparkplug".
Sure, but the fusion step is still important and somewhat poorly understood, so ICF experiments which mirror the conditions inside the fission-fusion step could be valuable for increasing yields.
Interestingly, a lot of recent developments in warhead design (e.g. the non-spherical primaries of the W-88) are actually about primary design - so I guess its possible this kind of research also feeds into the fusion boosting component of primaries.
I don't think it will as it should be radically cheaper. It should come with an economic improvement.
Given the current trends, it seems very unlikely that fusion will be even close to competitive with solar or wind by the time it arrives (which is still probably more than 20 years away as a commercial endeavor).
Fusion, in any of its forms, requires some of the highest technology ever produced by mankind. It then exposes these ultra-high-tech wonders to extreme temperatures, and extreme temperature differences, and large amounts of extreme radiation (neutron bombardment), plus corrosion from the extremely fine hydrogen gas. Initial fusion power plants will operate at a very small energy efficiency, and they will need constant maintenance via high-tech robots capable of withstanding the radioactive environment that the neutron bombardment will create all around the reactor. Most pieces of the reactor will probably not last for more than a few months or at best years, due to all of the pressures described before.
Not to mention, the potential for catastrophic failure, though much less than with fission, is still enough to completely destroy the reactor and a good chunk of the plant, if the plasma containment fails. While of course incomparably safer than a fission reactor meltdown, it would still be a massive economic issue.
So commercial fusion, when it does finally arrive (or if), will be extremely expensive, with its only plausible use case as a somewhat reliable base load. Cheap fusion, if it is even possible, is much further away into the future than that - I would confidently bet that cheap fusion will not exist this century, even if ITER or others reach all of their milestones as planned.
It's not that catastrophic failure destroys a good chunk of the plant, it's that any accident in the hot part of the reactor becomes very difficult to repair. So even a relatively minor accident can turn your multibillion dollar investment into junk.
It might be in the long term, but the same can essentially be said for nuclear (fission) power – the materials cost is low (compared to fossil fuels), but due to the extremely high capex needed to build a plant it's considered expensive.
I think the first ~50 years of fusion projects are likely to be very expensive and I'd expect that reputation to stick.
Depends on the return. Solar was too expensive until it was a better investment then a coal plant.
Why should fusion be radically cheaper? It's very complex, has much lower power density than fission, and pushes materials and systems more strongly (power/area through surfaces, for example; neutron flux as well) than fission.
If you claim either fuel cost or waste handling cost, neither of those is a major part of the cost of fission power. Capital cost is, and fusion moves that in the wrong direction.
Fusion is "cheap" if the externalities are priced in. (Of course that's currently a very big if.)
But even then, assuming a version of "fusion tech currently in R&D" realized today, we can probably build a lot of windmills and battery parks for the price of one fusion power plant.
Again, on the long term it seems ideal. (It can be made portable, abundant fuel in the universe, safer than fission, etc.)
And, will electrons generated via fusion be easier to track so that the government knows what you r doing with electricity
I don’t understand the appeal of this type of fusion (as opposed to the plasma reactor approach). We’ve known how to get positive energy out of fusion fuel since thermonuclear weapons in 1952. The really hard part would seem to be capturing that energy efficiently. This experiment is stuck at the ignition phase. When that’s positive energy they won’t be done, they’ll be able to start working on the practical problems of sustaining it. What am I missing.
What you're missing is that since the Comprehensive Test Ban Treaty came into effect it's illegal to test-detonate nuclear weapons. Which are narrowly defined in terms of fission devices, with or without a fusion booster.
Fission devices have been very well understood since the early 1950s, but fusion reactions are somewhat less so. The NIF provides an instrument for probing the plasma densities and temperatures that occur inside a nuclear fireball, so is directly relevant to H-bomb research.
This becomes trivially obvious when you realize that a laser implosion fusion reactor producing power would need to achieve in excess of ten ignitions per second to produce the sort of power output needed just to power its own lasers ... and that each hohlraum costs on the order of a third of a million dollars. (What kind of power plant costs $11Bn per hour to operate?) Answer: it's not a remotely practical design for generating electricity, so it must be something else, and promoting it as "clean energy from fusion power" is a cynical propaganda move to disguise a nuclear weapons research tool.
The final clue is that the NIF is operated by Lawrence Livermore National Laboratory, whose primary job is designing and ensuring the reliability of nuclear weapons.
This is why I often read the comments more than the articles here on hacker news.
> We’ve known how to get positive energy out of fusion fuel since thermonuclear weapons in 1952
Indeed, the brute-force approach is to simply detonate a hydrogen bomb underground, tap off steam, then repeat. That was seriously investigated (I believe as part of Project Plowshare https://en.wikipedia.org/wiki/Project_Plowshare ), but the high cost of the bombs made it uncompetitive with other methods.
I suppose you could look at it as a spaceship.
We have know for centuries that all you need to go high is a big fire pointing down, but soon realized that the hard part was maintaining the fire long enough to reach orbit or other planets.
And even when that would become possible, the problem of how to land in the destination, build shelters and grow food remains.
So, why we insist on this irrational pursuit?
First because we can.
Second because the the search needed to achieve that generates far more societal benefit than just the space goals.
And third because society can pursuit many goals at once. We have several people, just let them explore.
So, fusion is hard, but very probably not impossible. The pursuit of it will advance science and technology. If successful, can trigger societal changes we can only imagine today (serious carbon capture becomes possible. Smelting of very energy intensive alloys becomes cheaper and possible).
And if the ultimate goal of a miniaturized reactor becomes possible, our spaceships can fly basically anywhere.
There was a project to collect energy from thermonuclear bombs by blowing them up in an underground chamber cooled by a shower of molten salt. It was abandoned because the cost of making the bombs was too high, not the energy capture.
I don't know, what are you missing? You have fairly accurately listed the facts to the situation as it stands.
This is where we are at, that is what we are aiming for.
That fusion is not fission?
Thermonuclear weapons use fission to ignite fusion, and is how modern nuclear weapons work. Developed in the early 1950’s.
My guess is they are actually researching femtotech.
ED: By now I assume I would be ignored if I was wrong.
Until now Nuclear Fusion has produced optimism, careers and portfolio valuations but no energy.
The theory is there, but the implementation is not and worse than that, there is no "it will get cheaper with industrialization" in sigh, because we are not even at that stage and there is no indication there is a realistic path to achieve the efficiency needed to be economically viable ( ever! ).
The best positioned to deliver something tangible seems to be ITER, many of the rest seems to be more of a pump & dump scheme than anything else.
ITER may deliver something tangible, but also something that is not on any realistic path to being competitive. It's far too large for the power it (or DEMO) would produce.
It's also possible ITER will just deliver a negative outcome, if they can't figure out how to control disruptions sufficiently. A reactor that violently breaks itself is not something anyone would want to buy.
The primary reason for this is the use of Nb3Sn LTS confinement coils. REBCO is the next wave.
ITER has volumetric power density 400x worse than a PWR reactor vessel. ARC as described in the arxiv paper is just 40x worse. Better, but not by enough.
Can someone ELI5 to me how this design would be industrialised? How do you repeat this process day in day out?
Whenever there are articles written about inertial confinement, they always describe the current process (which I understand at a layperson level) but never how this design could be implemented in a repeatable manner?
More energy output than input such that output powers the input and so is a firehose of free money until energy no longer has monetary value.
The initial investment may be scary, but I think this is discounted per people's experience with Moore's law (whether right or wrong).
> until energy no longer has monetary value.
"Energy too cheap to meter" was already an obvious scam with nuclear power in 1954* (because plants obviously cost TONS of money to build/operate/decomission).
I don't see how fusion power is going to change that.
edit: * "Obvious scam" might be a bit harsh, but it was definitely naive overenthusiasm at the very least.
I understand the first cycle of the process - my question is how do you repeat the cycle?
I'm trying to ELI5 here, so, "keep dropping heavy-water pellets and pulsing laser beams."
That doesnt sound simple to me. But maybe it is?
A single pellet contains a lot of atoms. The current process is able to fuse some of those but soon the plasma cools down.
The goal is to start fusion by compressing the pellet using lasers and then use magnets to keep the plasma (charged, very hot gas/thing) confined to a small volume and hot enough so fusion becomes a chain reaction until all atoms of the pellet becomes a heavier element, when fusion stops (because a much higher temperature and pressure is required to fuse those).
This will generate a lot of energy which you car harness capturing the heat (by stoping the neutrons it emits or other method).
Use that heat to vaporize water to very high temperatures and use the high pressure to squeeze it through a pipe and then to push a generator.
So, this is a pulse thing. Pellet, laser, fusion, discard. Repeat.
In this case, is the pellet the highly precise gold holhraum described in the article? If that is the case, then isn't this whole thing obviously doomed to failure, given that the entire advancement described consisted of even more sophisticated methods of producing that holhraum?
The gold thing houses the pellet. It’s needed because the lasers by itself cannot compress the pellet. It’s the heat from the lasers that causes the gold thing to compress the pellet to the infernal pressure needed to trigger fusion.
Ok, but isn't the gold thing also essentially destroyed in the process? As far as I understand, for it to work,it has to be supremely smooth, or ot fails to generate the required patterns. Can it be re-used for a second pulse, after it is exposed to the thermal stress of the millions of kelvins and the mechanical stress of the explosion?
Destroyed.
So the extremely precisely machined piece of heavy metal is essentially part of the fuel. That seems like a no-go for commercial energy generation without any firther discussion.
Could someone enlighten me how laser fusion of prefabricated pellets (at least that's how I understand the idea in the article) can generate electricity? In a Tokamak or Stellarator, we collect heat on the outside, AFAIK and generate electricity in the good, old, "make something spin quickly" manner. But in a laser-ignition device, we need to shoot a pellet into some kind of chamber, so that chamber better be relatively cool or our pellet melts or deforms before it can be hit by the lasers, right? So how does one tackle that problem?
Magnetohydrodynamics converting ion current into electrical current is often floated but seldom explained in detail.
I get the impression that the rate of progress is increasing in fusion energy research. Finally!
Or is it just various fusion startups making PR waves to get more investments?
NIF is a national lab. Haven’t read this article yet but they made somewhat unexpected progress.
NIF is inertial confinement fusion. Magnetic confinement fusion startups have been making waves because of a new type of magnet which doesn’t need to be supercooled and can create the same amount of magnetic pressure w a smaller device (I think). In addition to that, there are the same old and not-so-old publicly funded experiments which have been making good progress of their own. ITER is still being built, but a lot of these publicly funded experiments are tied to ITER.
Fusion is reaching (or arguably has passed) its sell by date as alternatives crash in cost. So it's raise money now or never.
Great! Does that mean fusion is going to be here in just 10 years in the future as opposed to the 20 years in the future it's been for the last 50 years?
Who knows. The problem is not getting fusion, but getting fusion to economically produce power. Hopefully one of the startups figure out some way to make it work.
I have a hard time seeing the NIF approach becoming economical. It's more of a science experiment.
And very likely a weapons experiment, as has been said by others. This kind of indirect ICF is the closest model of what happens in a thermonuclear weapon.
Now that china is advancing with its mini artificial Sun, you can be sure the west will do whatever it takes to "catch up"