MIT-designed project achieves major advance toward fusion energy
news.mit.edu
news.mit.edu
Fusion energy was actually making rapid progress in the latter half of the twentieth century, going from almost no power output in the fifties and sixties to a power output equal to 67% of input power with the JET reactor in 1997. By the eighties there was plenty of experimental evidence to describe the relationships between tokamak parameters and power output. Particularly that the gain is proportional to the radius to the power of 1.3 and the magnetic field cubed. The main caveat to this relationship was that we only had magnets that would go up to 5.5 Tesla, which implied we needed a tokamak radius of 6 meters or so in order to produce net energy.
Well that 6 meter tokamak was designed in the eighties and is currently under construction. ITER, being so large, costs tens of billions of dollars and requires international collaboration; the size of the project has led to huge budget overruns and long delays. Recently however, there have been significant advances in high-temperature super conductors that can produce magnetic fields large enough that we (theoretically) only need a tokamak with a major radius of about 1.5 meters to produce net gain. This is where SPARC (the tokamak being built by the company in the article) comes in. The general idea is that since we have stronger magnets now, we can make a smaller, and therefore cheaper tokamak quickly.
Small tokamaks do have downsides, namely that the heat flux through the walls of the device is so large that it will damage the tokamak. There have been breakthroughs with various divertor designs that can mitigate this, but to the best of my knowledge I'm not sure that CFS has specified their divertor configuration.
This was just a short summary of the presentation by Dennis Whyte given here [0]. I do not work in the fusion community.
-Fusion has made consistent improvement, roughly in line with expectations for the level of investment (20 years away predictions were considering if we invested massively, which we did not).
- Fusion is in theory something that could give us true energy abundance. Want to just desalinate water like crazy? Want to extract gigatons of carbon? Working fusion enables these to happen woth existing technologies.
I like to think of solar, batteries, fission, and wind as compelling ways to go mostly carbon free and lower energy costs about 2x over the next 20 years or so.
Fusion is what reduces energy cost potentially another 10x, which really changes the game for lots of things. Exciting stuff. Kudos to this team.
Well, at least for a few hundred years but then:
> if you plot the U.S. energy consumption in all forms from 1650 until now, you see a phenomenally faithful exponential at about 3% per year over that whole span. The situation for the whole world is similar. […] the Earth has only one mechanism for releasing heat to space, and that’s via (infrared) radiation. We understand the phenomenon perfectly well, and can predict the surface temperature of the planet as a function of how much energy the human race produces. The upshot is that at a 2.3% growth rate [in energy consumption] (conveniently chosen to represent a 10× increase every century), we would reach boiling temperature in about 400 years. […] And this statement is independent of technology. Even if we don’t have a name for the energy source yet, as long as it obeys thermodynamics, we cook ourselves with perpetual energy increase.
Source: https://dothemath.ucsd.edu/2012/04/economist-meets-physicist...
The population will most definitely not continue to grow (in fact it will start to decrease slightly the more countries reach "developed" status), and the energy consumption per-capita will also stagnate. After all, there is a huge difference between going from living in a log house to a modern apartment with utilities and AC, and not much of a difference between one laptop and a slightly better one some years down the line. Also, attitudes towards environmental protection are changing with the generations so we are likely making different decisions 50 years from now.
If you increase the amount of energy flowing into the human body, the metabolism increases as well (although almost never proportionally - there are many variables) to compensate.
Similarly, it's rather unlikely that humans will continue to use exponentially increasing amounts of energy, unless we intentionally do something to effect that. Human population growth, which is partially driving energy consumption, is not exponential (it would be exponential absent of resource constraints or cultural factors, but guess what - both of those are in effect rather strongly in the real world) - and neither is energy consumption per capita. For instance, from 2005 to 2020, the US gained 30M people[1] while keeping energy consumption roughly constant[2].
[1] https://datacommons.org/place/country/USA [2] https://www.statista.com/statistics/201794/us-electricity-co...
The same goes for infinite growth. In the close future it sure looks infinite, but I'd say it's infinitely hard too to predict what will happen in say a 100 years (a fourth of the time before we hit the heat death wall predicted here).
I wonder, in a strictly thermodynamic way (ignoring CO2 etc), how big of an impact it would have to remove all internal combustion engines in land-based transportation and power generation (coal plants).
ICE's have like a 30-40% efficiency? Compared to electric engines 80-90%. But on the other hand, you probably consume quite a bit of energy producing the batteries...
How to tell an undereducated journo.
How did you arrive at that conclusion?
Fusion power plants still need land, buildings, generators, switchyards, wire, own power consumption, environmental impact reports, planning permits, regulations, inspections, and all the rest. And they need exotic materials and weird engineering in their construction.
Really: how does fusion get us to ~1% (correction: ~5%) of current power prices?
I've never seen a convincing explanation. Usually it's bare assertion. Infrequently it's handwavium/unobtanium.
But with fusion the endless claims of "too cheap to meter" are because how much energy there is in a fusion reaction. [0] We know that fission produces a lot of energy (but is expensive) but fusion produces significantly more. It also doesn't have the radiation drawbacks and so it is expected to follow the S curve (fission did initially but things changed. This is part of why France has so much nuclear).
So if (big if) fusion does follow this S curve (which there are good reasons to expect it to) then it could provide a very cheap and sustainable energy source. Yes, it is a bet, but every technology is. We won't know until we spend significant time and money into researching it. But honestly, a few billion dollars isn't that crazy for the potential upsides. We've spent that money on far greater risks with lower payout. Despite what the OP said, the money for ITER does not require international collaboration. Any rich country could do it themselves.
[0] (Fission and fusion can yield energy graph) http://hyperphysics.phy-astr.gsu.edu/hbase/NucEne/nucbin.htm...
Paper studies of fusion reactor designs given an availability figure, but this is mere aspiration, chosen because that number is necessary, not because it known to be achievable. The few actual studies of how available a fusion power plant would be (using MTBF and MTTR figures from related technologies) have come to very troubling conclusions: the plant may be operating just a few percent of the time. Getting fusion technology to the point where working reactors aren't perpetually down for repair is even more important than developing materials tolerating higher neutron displacements-per-atom (because it's hard to do the latter without the former). This requires building an experience base with all the kinds of things that will go into a fusion reactor. It also argues for making fusion reactors as small as possible (so there are fewer things to break); this is probably the best argument for these small high field devices (but an even better argument for high-beta plasma configurations).
The biggest problem is the 'in theory' part. With current plausible designs, the vast majority of the fusion reaction's energy is carried away by high-powered neutrons, which are entirely waste products.
I mean if we 10x the waste heat that could be produced by asics solely for the purpose of mining coins, it could be enough to create a mini climate.
There is nothing about fusion that makes it essential for putting carbon back into the ground.
> Fusion is what reduces energy cost potentially another 10x, which really changes the game for lots of things. Exciting stuff. Kudos to this team.
Citation needed... If the fusion reactors end up needing tape of room temperature superconductors to keep their confinement going, and they degrade rapidly due to neutron radiation, I could easily see solar being cheaper in the long run. I'm not saying this is exactly what will happen, but I have never seen compelling proof that fusion will really be so cheap in terms of capex or opex per Watt.
What does fusion give us that existing nuclear power plant tech doesn't?
The energy generated per unit mass in a fusion reaction is ~9 times that generated in a fission reaction[0]:
Considering the mass of the four protons/hydrogen
nuclei (4.029106u) and the mass of the Helium
produced (4.002603u) we get a mass difference of
0.026503u or 24.69MeV. So it is easy to see that
fusion reactions give out more energy per
reaction. However, the energy per unit mass is
more relevant. This is 0.7MeV for fission and
6.2MeV for fusion so it is obvious that fusion is
the more effective nuclear reaction.
The phrase "electricity too cheap to meter" is likely somewhat hyperbolic, but in comparison to pretty much any other mechanism fusion is enormously more productive and efficient.
Water is more abundant than Uranium?
Not much more nor less, since the amount of Bitcoin generated every 10 minutes is controlled by an algorithm independent on how many machines are mining.
I have a couple of physics degrees, hot fusion is the energy of the future and it always will be. This is not a physics problem, this is an engineering problem and we are just not willing to invest enough money to solve the engineering.
You're spot on. Which makes no sense at all. Given the potential of commercial fusion, we should be (globally) spending at least several tens of billions per year on R&D.
Assuming the engineering issues are solved, those hundreds of billions would be chump change compared to the economic benefits of volume of cheap, clean power.
It just doesn't strike me as obvious that reducing the major radius by a few meters would have such a huge impact on cost/timelines.
[0] https://library.psfc.mit.edu/catalog/online_pubs/iap/iap2016...
This quote from the presentation summarizes it well:
“The more money that's involved, the less risk people want to take. The less risk people want to take, the more they put into their designs, to make sure their subsystem is super-reliable. The more things they put in, the more expensive the project gets. The more expensive it gets, the more instruments the scientists want to add, because the cost is getting so high that they're afraid there won't be another opportunity later on- they figure this is the last train out of town. So little by little, the spacecraft becomes gilded. And you have these bad dreams about a spacecraft so bulky and so heavy it won't get off the ground- never mind the overblown cost.”
“That boils down to the higher the cost, the more you want to protect your investment, so the more money you put into lowering your risk. It becomes a vicious cycle.” - Rob Manning, Chief spacecraft engineer, JPL
SpaceX's advancement is impressive, but if NASA had never happened, I doubt SpaceX would even exist today.
>In 1992, Dan Goldin became the NASA Administrator. Goldin believed in a philosophy of Faster… better… cheaper—i.e., he thought NASA could do more with less. Hence, Goldin did not support the idea of having large EOS platforms in space and in fact once referred to them as “Battlestar Galactica.” He believed smaller, less expensive missions that could be built more quickly were the way to go and supported development of new programs that actually diverted funds from EOS.
[1] https://eospso.nasa.gov/sites/default/files/eo_pdfs/Perspect...
It's all completely bespoke scientific equipment hand made for this project only. The cryostat will be the largest stainless steel vacuum vessel ever made-- all welded by hand.
After welding, a substantial number of in-vessel components have to be installed by threading them through access ports, which is also quite a task: https://www.youtube.com/watch?v=pt70mO2nQac
That said building the first is a lot harder than scaling it up.
>It just doesn't strike me as obvious that reducing the major radius by a few meters would have such a huge impact on cost/timelines.
It would, easily. Past a certain size, production costs rise exponentially and require one-off tech.
Or is it massive like the tokamak is a 6 meter engine to a 100 km collider? Like there's a ton of other stuff being built in a massive structure?
1. As budget constraints tighten, the number of man-hours spent wrestling with bean counters (and/or waiting around with nothing to do until the bean counter wrestling completes) increases exponentially.
2. "Cheap solutions" often end up being unfit for purpose, and have to be reworked later at great expense.
3. Budget overruns lead to time overruns which lead to more budget overruns, ad infinitum.
Being delayed imposes costs on downstream work, which must now be ready but in some kind of holding pattern, which imposes costs on work downstream of that work.
So a large part of throwing "Manhattan project" / excess funding (and the potential savings by just funding it that way from the start) is avoiding these delays, to the extent possible.
It costs +$200,000 to tackle some challenge in a critical piece? Sometimes it's cheaper just to pay.
So there’s very little incentive to constrain costs.
We see it lately in the numerous military procurements (particularly the F-35 program), in NASA's SLS rocket, in California's bullet train to nowhere, and urban tunnels such as New York's 2nd Avenue subway extension. It is why nuke plants are invariably so expensive and late.
In a word, corruption.
Lately, this corruption has been arranged to be wholly legal, so there is no possibility of prosecution. The majority of the money spent is funneled into myriad private pockets without moving the project toward completion. Nobody involved, at the monetary level, has any desire for it ever to be completed, because that is when the gravy train stops.
Fusion projects represent the worst case of this phenomenon. Nobody knows what it should cost, and nobody in control of spending wants it over with, ever.
The chance that anything of any practical use could come out at the end was openly foreclosed before it ever started: it was never promised to produce any electrical power, and no turbines, or space for any, appear in any site plan.
Any sort of practically useful Tokamak plant would need to be overwhelmingly bigger and more expensive than ITER, and could never come anywhere near producing commercially competitive power, so the project is a known dead end, to be milked until it is finally cancelled in shame.
What is tragic is that each euro diverted to this boondoggle brings climate disaster terrifyingly closer.
The sole fact that such a scientific undertaking can be done internationally, over decades, is a great thing considering the global problems we face.
Yes, ITER doesn't follow the USA economic ideology of "much", "cheap", and "now", but the world doesn't consist only of the USA and not everything works well with that ideology.
ITER is not a PV or battery factory. It is more like the ISS.
Akin's law of spacecraft #29 "To get an accurate estimate of final program requirements, multiply the initial time estimates by pi, and slide the decimal point on the cost estimates one place to the right."
A 6m device occupies 666 (say) --216 m^3
a 10m device occupies 10 10 6 (say) -- 600 m^3
The scale of volume means that you have to build a much bigger facility to put it in (in order for the electronics to be kept dry and for people to be able to get around it to keep birds off it and things.
But worse - the weight. Concrete is 2400kg m ^3 so the small device might weigh 518 tonnes, but the bigger device is 1440 tonnes, so moving parts of it round becomes 3 * harder, the floors have to be 3* stronger, the supply chain has to be 3* better.
And then time - 3* scale, 3* engineering challenge -> many times more time to deliver, many more $$$ -> risk -> planning -> admin... the less capital at risk the less it's worth spending on avoiding the risk.. the less the overhead of the project is.
FWIW ITER is a science experiment - it's designed to find out more about fusion and that data will be very valuable for future reactor designs.
It's not that simple. The big problem with magnetic confinement fusion is that you need to control turbulence in the plasma so that you can contain the reactions for a reasonable amount of time to extract useful energy. However, turbulence increases with stronger magnetic field gradients, which is exactly what you get when making a smaller reactor chamber with stronger magnets. This wouldn't be the first project claiming to be able to build a small reactor, only to discover that it's virtually impossible without a major theoretical breakthrough. This is usually left out in the venture capital advertisements for these fusion startups. There's a reason why so much money and effort is spent on ITER - it is the only more or less guaranteed path to fusion with the tech and knowledge we have today.
Mmm, this isn't right. The stronger magnetic field reduces turbulence, it's the gradient of the pressure that generates turbulence. As best as anyone can tell, SPARC should be able to get Q~10 without any miracles involved -- the engineering rules of thumb and the advanced simulations all say the same.
https://www.cambridge.org/core/journals/journal-of-plasma-ph...
That's why I specifically said field gradients - i.e. the thing that gets larger when you have a stronger field in a smaller volume.
>it's the gradient of the pressure that generates turbulence
How exactly do you think that pressure is created?
Also, that link you provided is an editorial from one of the directors behind SPARC. If you want an objective analysis that is not geered towards possible investors, you need to look elsewhere. FYI, anyone selling you Q~10 designs without a considerable theoretical breakthrough is almost certainly conning you. If you don't believe me just look at how Lockheed's compact fusion reactor panned out. Stronger magnets are not some kind of miracle solution that will enable fusion tomorrow.
Maybe your equations and power laws are right, and a "big enough" tokamak would be a competitive source of power. But then there are the details, like "big enough will cost $25 Trillion". Followed by delays, cost overruns, etc.
I'm thinking that a rational, non-expert taxpayer would say, "This fusion thing is a hundred times worse than NASA's Senate Launch System. Stop wasting my money on it NOW, and let gullible investors waste theirs instead."
VIPER: an industrially scalable high-current high-temperature superconductor cable
Most notably, the extreme temperatures, hydrogen pumping, and high-energy neutron bombardment mean that, even with liquid metal blankets, the reactors will very quickly become brittle, probably not lasting more than a year or two. Since neutron bombardment also turns any material radioactive, not only do you need to tear down your fusion plant (or at least the expensive reactor part of it) every few years, but you have to do it with radiation-resistant robots, as human workers can't get close to the reactor after it's been operating for a while.
This talk by the MIT Nuclear Science department head explains the whole rationale behind ARC/SPARC, and this timestamp is where he starts talking about maintenance and the neutron blanket (5 minutes later): https://www.youtube.com/watch?v=KkpqA8yG9T4&t=2400s
I bought a new screen cover yesterday for my phone. It came with a full mounting kit that I discarded after the ten minutes that took me to place the cover. The same kit could have been used to mount at least a hundred covers. The small slice of civilization I'm part of is extremely wasteful!
But, let's analyze that waste. First, energy went into collecting and transporting those materials, plus collateral environmental degradation. Now, energy will be spent collecting and processing my waste, and if it can't be recycled, it will end up also provoking collateral damage.
But, if we had infinite cheap energy, recycling all of it would be a no-brainier. Even recycling materials contaminated by radiation would be easy; after all, we already do that to refine fission fuel.
Economic incentives? Those are trivial to legislate, absent the environmental cost and with a promise of green-house gases neutrality. Heck, had we infinity cheap energy, we can pack, move out of planet an leave all of Earth as a bio-reserve.
In other words, nuclear fusion holds the promise of being such a civilization game-changer, that the question of "is it better than solar in the next ten to thirty years?" is moot. With that said, the next ten to thirty years will be vital to attenuate climate change, so nuclear fusion should not be used as a deterrent for other climate investments we can do today.
The only useful outcome of any of this work is a generation of plasma-fluid physicists with practical experience. Pray we can find them something useful to do when the whole enterprise finally collapses.
Chiefly, how does that further the conversation? More pointedly, why should we listen to you?
Credentialism in this arena is valid, and what I currently see are multiple subject matter experts, albeit with a bias/incentive towards believing in themselves, versus you. Please substantiate your claims, or word them more carefully as to reflect them being conjecture.
A whole generation heard about it in school decades ago. Multiple generations by now, even. Its right up there with battery/energy-storage technologies. Headline after headline, enrapturing a newer and newer idealist set of people to quickly become disillusioned. People just get tired of it.
But I’m glad to understand whats going on behind the scenes now. I’ll pay attention. Looks like a real sleeper.
So, why is this particular announcement exciting? There are 3 factors:
1. This is a high temperature superconductor. I can't find any references, but as far as I remember the substrate they are using needs to be cooled to (WRONG, it was cooled to 20degK, see reply by MauranKilom) 60-70 degK to achieve super conductivity. Compare to magnets used in ITER which need to be cooled to 4degK. This is the difference between using relatively cheap liquid nitrogen vs liquid helium.
2. Field strength of 20 Tesla is significantly higher than 13 Tesla used in ITER. Given that magnetic confinement fusion scales significantly better with field strength vs reactor size, this will enable much smaller reactor to be power positive. See following links for more details on ITERs magnets: https://www.newscientist.com/article/2280763-worlds-most-pow... https://www.iter.org/newsline/-/2700
3. Finally, the magnet was assembled from 16 identical subassemblies, each of which used mass manufactured magnetic tape. This is significantly cheaper and more scalable than custom magnet design/manufacturing used by ITER.
The kicker is how 3 of the factors above interact with the cost of the project. Stronger magnets allow smaller viable reactors. High temperature superconductors + smaller reactors allow for a much simpler and smaller cooling system. Smaller reactors + scalable magnet design further drives down the cost. Finally, cost of state of art mega projects scales somewhere between 3rd and 4th power with the size of the device. Combining all of the above factors, SPARC should be here significantly sooner than ITER and cost a tiny fraction (I would guesstimate that fraction to be between 1/100 and 1/10,000).
edit: typos + looked at the cost of ITER and refined my cost fraction guesstimate + corrected some stuff based on the reply by MauranKilom.
> This is because energy gain and power density scale exponentially with magnetic field strength but only linearly with reactor size
Nit: It scales polynomially, not exponentially. Specifically (according to those formulas) energy gain scales with the cube of field strength and power density with the fourth power. Still massive scaling indeed, but exponentially would be something else.
> as far as I remember the substrate they are using needs to be cooled to 60-70 degK to achieve super conductivity
The video in the article shows 20 K. Could of course be that higher temperature is feasible and they just played it safe (or the video is wrong).
But they don't need to, do they? If their claim is sound, they could as well just optimize the magnets and wait for ITER to complete to offer an ITERation (pun very much intended) on the design. The fact that they focus on this weird race against an international research project makes me wonder if SPARC is mostly a vehicle to attract investors.
ITERs plasma density will be comparatively low, and that is where SPARC with stronger magnets comes in. SPARC will produce data on lower volume and limited burn time, but significantly higher plasma density.
The new superconductors that allow these larger magnets are also very recent, not in discovery but in actual mass production. So they don't have as much experience with using these as with the classical superconductors. So I hope there is still quite some quick improvement there on the table.
If I remember right from one of the videos from the SPARC reactor folks, they were experimenting with not bothering with insulation between the magnet windings. The ReBCO film is bonded to a layer of stainless steel, and they figured the conductivity of the film is so much better than stainless steel that they wouldn't actually get much loss from current leaking through. That seems kind of crazy, but I guess there's a lot of things about superconducting materials that don't behave intuitively.
Maybe manufacturers can make film that's bonded to a thinner layer of stainless steel or whatever, and thus allow for more windings in the same space?
One purpose of the support material that isn't super-conducting is thermal protection. If your superconducter quenches, you have to dissipate the energy contained in it without destroying the magnet. In classical ones they use copper wire around them as far as I remember, and the high-temperature ones are a very thin film of ReBCO deposited on metal tape, so the actual superconductor is always a small part of the material.
This is D-T fusion. Which means you have to have T. Which currently comes from fission reactor and has a half life of 15 years.
So the plan is to use a molten salt blanket with Be to breed T. But Be isn’t scalable for consumption, so maybe lead eventually. That’s probably do-able, it just slows down the rate new reactors can come online since Pb is not as good a neutron multiplier.
Once they breed extra T, they have to capture and refine it. Hydrogen is very corrosive and hard to work with… and T is radioactive hydrogen. Again, probably doable. But guess what? Refining spent nuclear waste in fission reactors is also do-able. It’s also super expensive.
And they still need a containment vessel that will withstand the wear and tear from sitting next to a mini hydrogen bomb all day.
These challenges are likely all surmountable. But are they surmountable AND cheaper than existing nuclear or other energy sources? Meh?
Though most of the reactors do not harvest the tritium, a small number do.
CANDU operators have long been ready to make the capital investments in tritium harvesting, once demand materializes. ITER has long been seen as a potential major source of tritium demand.
Also thinking, we target deuterium + tritium fusion because it's the least energy intensive. However, once we have working proof of concept reactors, could we just make them slightly bigger and fuse more abundant molecules/isotopes instead?
I'll have to find the citation, but IIRC the answer is "theoretically, yes" - the concept is that molten lithium could be used in a tokamak to absorb neutrons and produce tritium at the same time.
EDIT: Here are two citations I was able to find quickly - it looks like one of the ITER experiments will be to validate the concept [1] and that this could also be the way that heat is removed from the reactor. [2]
[1] iter.org/mach/TritiumBreeding
[2] https://www.euro-fusion.org/faq/top-twenty-faq/what-is-a-lit...
Their plan is to use FLiBe (Google it) blanket to breed tritium. The Be acts as a neutron multiplier.
As for non D-T fusion, the next best candidate is D-He3. Unfortunately, the only large scale source of He3 is on the surface of the moon and it would have to be mined, on the moon, and sent back to Earth.
Not as bad as I expected but not yet feasible economic wise. Assuming the fusion part exists.
"Fusing two deuterium nuclei is the second easiest fusion reaction."
"The optimum energy to initiate this reaction is 15 keV, only slightly higher than that for the D-T reaction."
If we have to scale up fission reactors to produce enough tritium to scale fusion reactors, then don't need the fusion reactors.
DT fusion solves the two biggest arguments that are always raised by nuclear energy opponents: storage of nuclear waste (it doesn't produce high-level waste) and safety (it's not perfect but it can't explode). I wouldn't call it a "meh", even if it comes off as much more expensive than fission.
It's not competing with fission, though. It's competing with renewables + storage + load shifting + efficiency. Compared to those, it might indeed be "meh".
Until prices do start to bottom out, investment in storage is wasteful, so dollars go to generating capacity of known utility.
Each square meter of panel that goes online delays climate disaster by a precisely understood amount. Each panel made can go into service almost instantly. No matter how big the project, it can start delivering power anytime. There is no smallest-useful facility, right down to the residential rooftop.
Every dollar diverted to Tokamak instead brings climate disaster nearer.
This is not intended as a rant against solar (again, I'm an enthusiastic supporter), but I'd guess a landscape of fusion generators would take fewer square meters of land than the equivalent using solar. And that is nothing to scoff at.
It is incredibly unlikely to offset the carbon related gains of solar, because the carbon sequestration efficiency of plants and trees is very low to begin with, far lower than solar's capacity to displace carbon emitted from coal when area is held constant.
Sure, it's better to put the solar where there is no existing tree cover, but it seems like most of Appalachia is covered in trees.
Renewables are key to having a sustainable energy economy. Fusion power is what will let us do the drastic things to recover from climate disaster that is already here.
It is: it's definitely the biggest challenge after plasma confinement.
> Molten isotopes salt and lead?
There are two main blanket technology in development: ceramic and liquid breeders. They're called breeders but are very different from the kind of breeders you have in a fission reactor. Both are based on converting lithium to tritium by capturing fusion neutrons, but in one case the lithium is in the form of solid pebbles, while in the other, in a molten mixture of lithium-lead (there are no salts AFAIK).
To produce more tritium than you start with you also need a neutron multiplier: beryllium in ceramic breeders and lead in liquid breeders. The problem is beryllium is rare (and also toxic): a 500MW reactor needs ~200 kg/year, which is not a lot, but there's very very little beryllium on earth. If you factor in the initial reactor inventory (170 t/reactor) it turns out ubiquitous fusion energy it's not sustainable if we choose beryllium. If you go with lithium-lead you need more material: 3 t/year (but remember lead is a lot heavier and more common too). If you plan to cover the world energy base load with fusion, you would need a lot of lead (~10% world annual production) but it's doable.
For me, the biggest problem right now is lithium: DT fusion needs lots of pure ⁶Li, which is extracted by enriching even more natural lithium. If we're not careful enough with recycling it from old batteries, we are likely to exhaust the world resources in a few decades.
> What do you do with when it goes bad? It may not go boom Chernobyl-style, but it's still far from the birds-in-the-sky deuterium-from-the-sea fusion dream.
The worst case scenario is still the loss of coolant accident (LoCA). The blanket is exposed to a ~2MW/m² heat load from the plasma (in addition to all kind of radiation), so failing to cool adequately a module means it will very rapidly turns into a (radioactive) molten mess that's not easy to handle. Yeah, it's bad but not nearly as bad as the same accident in a fission reactor.
https://en.wikipedia.org/wiki/FLiBe
> FLiBe is a molten salt made from a mixture of lithium fluoride (LiF) and beryllium fluoride (BeF2).
If we are lucky enough, none will be built.
Tritium is not pleasant though, but veeeeeeeeery far from anything that could do real harm: https://en.wikipedia.org/wiki/Tritium#Health_risks (you'd need to leak a lot of it continuously)
In the same way, a fusion plasma doesn't hold that much energy because of the extremely low density (4×10^-6 that of air). An explosion (a runaway/chain reaction) is also not possible: the reactor must continuously supplied with fuel or the fusion reactions will stop in a matter of seconds.
There are situations which could result in significant damage to the reactor components, but still not a public safety concern. Distruptions are events in which the plasma confinement is lost and a large amount of heat is released that could damage all components that face the plasma, but reactors are designed to withstand this.
Another drawback, if you like, are runaway electrons, which are populations of relativistic particles that become unbound and penetrare the vacuum vessel for several mm. Again, this is not a particular issue from a safety point of view, but they can do a lot of damage: if they hit a magnetic coil and cause a loss of the superconductivity state, the coil can heat very rapidily (due to the huge current that goes through it) and potentially melt. Replacing such a coil could cost years of maintenance, for this reason reactors are build with many fallback systems.
Costing hundreds or thousands of times as much as solar + storage is a more serious problem. Since it won't be built, that is a theoretical problem. But the project can absorb an unlimited amount of money first.
And you can burn up the waste majority of that waste, the leftover waste after that would not really a huge issue.
Both of these are far more political problems then actual real problems a society based on modern fission would have.
It does. You cannnot fuse just D+T, other trace gasses, and lighter isotopes will be present as well.
The radiative losses do exist, but are caused by detached atoms from the plasma facing components. Everything close to the plasma is made of light elements and specifically chosen to not produce dangerous radioisotopes when neutron activated: no high-level waste materials, meaning the half-life is lower that 10 years and they can be recycled in around 100 years.
[1]: http://www.iter.org/faq#Can_you_declare_fusion_is_really_saf...
"T is radioactive hydrogen": True, it emits low energy beta radiation, which is an electron, and is stopped by a sheet of paper. I used to have a wrist watch with a tritium dial; I haven't died of cancer yet.
I've never heard of hydrogen-filled balloons (at least not the kind of balloon you can hand to a kid) - we're you thinking of helium?
[0] unless Mark Rober is involved in some way.
For the other uninitiated, (or far enough out of secondary school and didn't take it further!) this seems to refer to Deuterium-Tritium fusion, D & T being the isotopes of hydrogen with an atomic mass of 2 (1 neutron, 'heavy' but stable) and 3 (2 neutrons, radioactive) respectively.
Very little is invested into fusion power as a project, overall. So advancements seem to come when outside influences cause breakthroughs.
I wonder how different the world would have been if it had for whatever reason been easier to produce fusion power than a fusion bomb. Military investment into the bomb would have probably pushed things forward a lot quicker. As is, the US military built thermonuclear bombs very quickly and then the appetite for advancement just dried up.
I really wish that press release would put the link to the paper at the top -- I found it very hard to work out what was actually new!
https://english.cas.cn/newsroom/research_news/tech/201912/t2...
Googling "30T magnetic field" shows some papers that have apparently "pulsed" 30T.
Q (the ratio of energy out to energy in) has improved by about four orders of magnitude since controlled fusion was first achieved, and it's been a slow, at least reasonably steady march since the middle of the 20th century to achieve that progress. The current record-holding Q for magnetic confinement is around 0.67, so we need well under one more order of magnitude to get to the point of "theoretical break-even" (Q>1) -- we're most of the way there. A plant just barely better than break-even probably wouldn't be commercially viable, though, and while estimates vary, that point is probably somewhere in the 10-30 range, so we have maybe another order of magnitude to go after break-even. I don't think there's anything to suggest that after decades of progress we'll suddenly stop being able to make more.
It's true that things have slowed down somewhat in the last 10-15 years, but most of the blame there goes to the need, in order to continue moving forward, to build bigger and bigger reactors, and the need to divert resources to that goal (mostly ITER). To the extent that promises of going faster have turned out to be hot air, it seems like they've mostly been in the form of novel approaches that do fusion in some fundamental new way that avoids the need to build an ITER-like thing. These approaches seem to often involve lots of unknowns, and end up getting bogged down in practical issues once they're actually tried (surprise plasma instabilities and so on).
Recent advances in materials science (mostly REBCO magnets) and computing, though, offer a path to progress on the regular, bog-standard flavor of magnetic confinement fusion (tokamaks) on a smaller scale -- that's what this is. The nice thing about that is that the plasma physics here are very well understood, and have been heavily researched using conventional/not-super-conducting magnets that won't ever achieve break-even, but create identical plasma conditions inside the reactor (MIT Alcator C-Mod is effectively the conventional-magnet predecessor to this project). Up until now, the only real question was whether or not they could build strong-enough REBCO magnets, and now they have, so this is all good news and reason for optimism.
Of course, commercial viability is a whole other question involving lots of questions besides physics. But the physics here seem to not be in serious doubt, unlike some of the proposals from other startups that are more exotic.
What sort of computing advances? Modeling? Real time controls? I'm guessing modeling, but would like to know more details.
There are a bunch of issues still to be resolved. Higher magnet strength is/was just one of many.
That it would cost overwhelmingly more than solar+storage is what will ultimately kill it. Someday. Many more $B will be spent first.
I feel that fusion is one of humanity's best shots at actively reversing climate change, and it is disheartening to see such widespread pessimism about it. Yeah it's hard. There are huge hurdles in making it economicly viable, but if we can go from first powered flight to the moon in 70 years, and put billions of transistors on a chip in 50, then maybe we can get fusion going. It's clearly possible.
Couldn't the same thing be said about current fission reactors?
I get that fusion doesn't have the downsides of fission... but I'm also worried that people will be "scared" of fusion in the same way they're against GMO vegetables and irradiated fruits, totally irrationally...
People are terrified of radiation, even if the danger is very low. This means it becomes prohibitively difficult and hence expensive to build and run a fission plant because safety has to be prioritized so heavily. That is even if permission is granted to build in the first place.
I think it is unlikely for irrational fear of fusion to become mainstream like it has with fission.
Because of this I think the barriers to fusion power are at this point lower than the barriers to scaling up fission power.
We can just rename fission to #goodenergy or something, that would be cheaper then developing fusion.
People don't even know that nuclear reactors use fission, so the idea that this would change anything is crazy. People opposed will call fusion reactors 'nuclear' just like they do fission.
If a Fusion reactor blows up, the radiation risk is basically 0, aside from the lack of potential melt downs.
Fusion does indeed come with radiological hazards: a fire could release radioactive gas and dust. If designed right, the worst-case scenario would still be way less severe than for a fission plant -- and the worst-case scenario is really what stokes all the popular fears about 'nuclear'. OTOH, tritium leakage could mean that routine emissions are larger.
The day-to-day danger perhaps, but it's kind of hilarious in a sad way to read this right after fukushima spent god knows how long leaking radioactive shit into the ocean.
Environmentally clean energy source is not enough, it needs to be ideologically pure as well.
There are all sorts of approaches to fusion, and things such as type 2 superconductors were undiscovered 30 ago and uneconomic/unpractical 10 years ago. Timing control systems for magnetised target fusion were impossible but now are doable. Our understanding of plasma has been advancing a lot, simulations are good now, we can control plasmas much better. Chirped pulsed laser amplification is a thing now and really good at making high amplitude pulsed lasers for inertial approaches...
I could go on and on. This isn't the 90s anymore, and our technology is still rapidly advancing. What happens if we find more efficient/cheap/high power density thermocouples, or find a direct energy electrostatic power capture method?
Fusion's economic realities today may be overcome soon, we really do not know what we can do in even 20 years from now. The fundamental truth is that there is vast amounts of energy available in hydrogen, and all it takes is 100MK to ignite it.
And then you have the problem of having to stick sophisticated stuff in the hot zone where hands-on maintenance is impossible (compared to a fission reactor, where just the fuel and relatively simple hardware is in that zone.)
The engineering undesirability of DT fusion has been known for decades. All the recent excitement doesn't address any of the known showstoppers.
I wouldn't call it that, even if there would be a energy gain.
I call it beginning of "fusion age", when we solved fusion ad can build them reliable and reproducible - and if we still need them by that time, for main energy production.
Since any fusion plant would necessarily cost more than 10x fission, and fission is not competitive, that is well out of reach.
[0] https://www.nature.com/articles/s41467-017-02641-7
Just as a note, the max B field here is 600T
https://nationalmaglab.org/news-events/news/lbc-project-worl...
Fusion power density scales like B^4. So if CFS can get 2x the magnetic field, then they can make the plasma volume 16x smaller, which might equate to big savings in cost and construction time. (It doesn't make sense to go much smaller than their ARC reactor design though -- the plasma already takes up only a fraction of the volume of the core at that scale, so compressing the plasma further doesn't improve the power density. If you can increase the field even more, which REBCO seems to allow, then you would rather just pack more power into a device about the size of ARC. So don't expect to put one of these on your DeLorean.)
There are definitely other challenges/limitations. For one, this approach increases the heat flux that the inner wall of the reactor will have to survive. The localized heat flux of the exhaust stream is expected to rival the heat flux of re-entry from orbit (20 MW/m^2) and could be as high as the power flux from the surface of the sun (~60MW/m^2). 20MW/m^2 is on the hairy edge of what's possible with today's technology, and that's without all the complications of neutron damage, plasma bombardment, etc. The current thinking is to spike the outer layer of the plasma with neon or nitrogen, to radiate most of the power as photons, but there are limitations & risks to that idea as well. Commonwealth's plan for SPARC (last I heard) was to oscillate the exhaust stream back & forth across the absorber plate to reduce the average heat flux.
The nuclear engineering side of fusion has been underfunded for a long time, so there's much that needs to be done on that front, in terms of demonstrating that the breeding of tritium from lithium can be done efficiently & without too much losses. Also, we should be developing better structural materials that can withstand neutron damage & not become (as) radioactive.
It's still very much an open question as to whether fusion could be made economical, even though it seems like it should be technically possible.
It doesn't look like they are targeting that here. Does anyone know if that is ARC (not SPARC) specific, or if that has been abandoned?
CFS will be building a lot more magnets, not only for SPARC but for other customers, physics experiments and medical equipment, so I expect they will be working on many additional features including demountable joints for ARC.
One of the early tests they did of the VIPER cable at the SULTAN test facility in Switzerland involved a joint formed by clamping the ends of two cables to a copper bar. It does show that resistive joints are possible with HTS cables, unlike LTS cables, but the actual configuration of a joint for a large magnet is obviously a different matter. Luckily they will have a few years to work on it.
So, sounds like it's for SPARC.
No commercial reactor will ever be built, so this is just for showing off.
The only real good to come from these efforts is employment of plasma fluid physicists. I just hope non-military work can be found for them when this stuff fizzles. Solar Physics is fascinating and important, but has limited budget.
Here's the truth: there's no such thing as free energy. Even if the fuel is so abundant it's actually or effectively free (eg deuterium), the energy isn't. Say it takes $50B to build a plant that produces 1GW of power, which I'll estimate at about 7TWh/year based on [1]. Let's also say it has a lifespan of 40 years and an annual maintenance cost of $1B going to up to $2B in the last 10 years.
So that's 40 years for 280TWh at a cost of $100B, which equates to $0.35/kWh if my math is correct.
I realize ITER isn't a commercial power generation project. My point is that people need to stop getting hung up on the fuel being "free". The lifetime cost of the plant can still make it completely economically unviable.
Second, the big weakness of any fusion design is neutrons. The problem people tend to focus on is that neutrons destroy your (very expensive) containment vessel with (one of my favourite terms) "neutron embrittlement".
As an aside, hydrogen fusion also produces high speed helium nuclei, some of which tend to escape and this is a problem too because Helium nuclei are really small so can get in almost any material, which is a whole separate problem.
But here's another factor with neutrons: energy loss. High speed neutrons represent energy lost by the system.
To combat these problems we've looked for alternatives to hydrogen-hydrogen fusion, the holy grail of which is aneutronic fusion. The best candidate for that thus far seems to be Helium-3 fusion but He-3 is exceedingly rare on Earth.
I really think we get caught up on the fact that this is how stars work but stars have a bunch of properties that power plants don't, namely they're really big and they burn their fuel really slowly (as a factor of their size), which is why they can last billions or even trillions of years. Loose neutrons aren't really an issue in a star and sheer size means gravity keeps the whole system contained in a way that magnets just can't (because neutrons ignore magnetic fields).
So I hope they crack fusion but I remain skeptical. Personally I think the most likely future power source is space-based solar power generation.
[1]: https://en.wikipedia.org/wiki/List_of_largest_power_stations
Space-based solar power generation (itself "fusion power" in the loosest sense) would be great in the inner planets.
Though to open up the outer planets, Kuiper belt, Oort Cloud, and any other stars, we'll need non-solar* power: hopefully fusion, at least fission.
*Unless we want to go the stellaser route, but I'd bet we'll crack fusion before getting near K2.
H-3 is not nearly so scarce as cletus suggests. It is uncommon, but you don't need much.
However, those maintenance costs (your estimates) would be the first thing to drop. Any company producing/operating these will be competing with wind and solar, and thus highly incentivized to improve. There should be plenty of low hanging fruit, since it hasn't happened once yet.
I think the hope is that with economies of scale, we could build really huge fusion plants one day, and drive down the cost of energy to less than a cent per KWh, and of course completely eliminate our dependency on fossil fuels. If energy becomes that cheap, we could use electricity to produce hydrocarbons from CO2 and water to power airplanes and such. Currently, we can imagine short-distance flights being electrically powered, but transatlantic flights are going to be difficult to achieve with batteries.
Space based power generation to me is incredibly dumb. It would be far easier to build solar on earth and transport it around with high efficiency DC lines.
And if you are really looking into the cheapest possible energy a thorium breeder reactor could run for ever with no fuel cost and could be built with 70s technology. These reactor be produced in a factory at a manufacturing line and then dropped into a containment facility.
How this should be more expensive then space based solar makes no sense to me.
This is what I remember from memory, I would need to fact check that.
My method uses much lower magnetic fields that could be provided by permanent magnets, but should allow containment times on the order of weeks for small quantities of D-D fuel.
I have more information at http://www.DDproFusion.com
In case others are wondering, looks like this is for SPARC.
FTA: This "MIT-CFS collaboration...on track to build the world’s first fusion device that can create and confine a plasma that produces more energy than it consumes. That demonstration device, called SPARC, is targeted for completion in 2025."
CFS: https://cfs.energy/technology
(edit: clarification)
ITER was designed to use weaker electromagnets and therefore needs a massive building and tons of cranes and a massive budget.
Unfortunately, the ARC design also had 40x worse power density than a PWR primary reactor vessel.
Viewed another way: if you could make a fission reactor with a power density as low as ARC, it would have so much thermal inertia that meltdowns would be essentially impossible. You should then ask why such fission reactors are not built.
As to why massive fission reactors aren't built: there are plenty of already-available passively-safe/meltdown-proof fission designs (many gen-IV designs qualify), and from what I can tell, the reasons they're not built are as much political as anything -- people don't like them, and the consequent regulatory regime has made any fission projects prohibitively expensive regardless of their size. None of this need be the case with fusion.
As to tritium: I think you're overstating the tritium risk. They're only dealing with grams at a time, and even if it all leaked out, it would rapidly diffuse such that risk to the public would be infinitesimal as compared to normal background radiation (plus its half-life is only something like 12 years). ITER has a safety page: https://www.iter.org/mach/safety that essentially says as much.
Tritium will be handled in such large quantities in a fusion reactor that even small leaks will be problematic. As I like to point out, the tritium made and burned in a 1 GW(e) DT fusion reactor in one year would contaminate 2 months of the entire flow of the Mississippi River above legal limits for drinking. Even small leaks could cause serious harm to property values (sorry, your ground water can't be drunk for the next 50 years.)
Gen-IV reactors aren't built not for political reasons, but because nuclear has become such an economic orphan that there aren't stakeholders to drive the construction of these things. The money isn't there because the ROI isn't there.
Smaller. Smarter. Sooner. 2018
Currently 2021 where is my fusion energy? But this time must be different, after this advance we are only a few years away from fusion energy?
They are now claiming to have done the latter. Are you skeptical of the new design? Or do you think it does not represent as significant a departure from earlier designs as they claim?
I really want this to work. I am a bit concerned, with how “the old guard” will react, once we have successful, productive, fusion.
I foresee an astroturf NIMBY campaign against construction of fusion plants.
They forgot to say that it is not the H2O that comes out of your tap. The earth is especially not full of tritium.
Deuterium is plentiful in tap water.
[1] https://books.google.com/books?id=KSA_AAAAQBAJ&lpg=PA234&ots...
Also, not sure why imgur has that image marked as adult content.
The 1976 projection was that, assuming funding was kept at the level of 1976 (~1 billion a year), fusion would not be achieved in the foreseeable future. It further shows that actual funding has been below that level.
In short: Yes, getting fusion off the ground sooner would have required more money. Not "always more", but more than "we project no success" levels.
https://www.reddit.com/r/Futurology/comments/5gi9yh/fusion_i...
FRC, though, maybe. But you would have to have people actually working on that.
Nuclear ruined it's own reputation for generations though hopeful not as long as they'll have to care for the waste we already have.
We are purely lucky that, for structural reasons, corruption is minimal on solar and wind projects. Probably this is because what it ought to cost is readily visible from the outset. There just isn't enough fat to attract graft.
"criticizing [The Death of Environmentalism: Global Warming in a Post-Environmental World] for demanding increased technological innovation rather than addressing the systemic concerns of people of color."
I won't even go into this baseless bashing of "environmentalists". It's cheap and disgusting. Some of them have dedicated their whole life to the cause while a shitty anthropologist bashes them while being paid by the same companies which pollute the planet.
The only real open question is how long the gravy train will run before the plug is pulled. F-35 and SLS have demonstrated that with careful management, that can be longer than anyone could have believed.
The goal is to get fusion power om the grid in the 2030's and scale up in the 2040's. Stop moving the goalposts.
The video thouches upon magnetic fields and its relevance at this time mark ; https://youtu.be/L0KuAx1COEk?t=2880
Fission has a absurdly high energy density, the step from oil to fission is far more relevant then the step from fission to fusion.
Fusion would mean basically no fuel cost, but thorium is already a waste product and even uranium fuel is a tiny part of any fission plant.
Some people seem to believe the fusion is inherently prove against weapons, but this is equally not really true. If you had a working fission plant there would be ways to use it to get what you want to make a weapon.
There are some places you might want fusion, mainly in space travel but even there we are not anywhere even close to where we could get to with fission. Open gas nuclear thermal rockets anybody?
In sum, I'm not against this reseach but its not a way to solve our problems anytime soon. Fission you could get to run with 60s tech and amazing reactors could be designed within decades and often with comparatively small teams in the 60-80s and somehow we haven't managed to make it competitive.
Fusion looks to be far more complex to build in every possible way. How this will be cheaper is questionable to me.
Haven't Tokamak Energy in the UK done better than this already back in 2019 with their 24T magnet based on similar HTS tape technology?
https://www.tokamakenergy.co.uk/tokamak-energy-exceeds-targe...
In comparison, 20T does not look much, but again it is, I wonder with the Japanese technique what is the highest continuous magnetic field.
[0] https://en.wikipedia.org/wiki/Explosively_pumped_flux_compre...
And I hope the marketers pretending they'll have a commercial plant by 2025 are ashamed.
For instance, can I build a railgun to shoot things into orbit?
Nah.
https://thebulletin.org/2017/04/fusion-reactors-not-what-the...
This is because a lot of rich countries seem to me to be well placed to benefit partially from global climate change at the moment, at least within the 1-2C range. Changing the climate past that point is likely to be controversial, since the countries who now benefit from the situation will likely not want to give those newfound advantages away.
I would think of it a lot as the end result of a war - the borders are defined by where the armies stopped ie the division of Europe and Asia after ww2. After climate change I expect whoever has benefitted from it to defend their position and reject any further alterations!
But every cent diverted to fusion from solar brings climate disaster closer.
Edit: also, your comments seem to be incredibly negative on fusion, would you mind disclosing if you have any solar or wind connected conflicts of interest?
My beef with fusion is about long-term hucksterism and wholly-legal corruption. STS, SLS, F-35, Big Dig, 2nd Ave, Cal bullet train, fission, fusion.
Dollars are fungible. Would fusion dollars otherwise go to renewables build-out? They might be more likely to go to battery, solar panel, superconducting power transmission, or carbon reclamation research. All of those would be welcome alternatives.
Even FRC fusion would be a better use of funding.