>"Frustrated by the slow progress, private companies [innovate]"
This is not about frustration, it's about opportunity:
After decades and billions spent on research and engineering, all "open source", and training a generation of plasma scientists, venture capital can hire these people into profitable ventures. I'd like to ensure these people are given proper credit, and actually make some money off their great contribution to humanity.
I fear that all we will do to reward greatest minds is give them mediocre jobs.
You can't expect exponential progress to continue forever in the world of atoms, so I disagree with your characterisation of "bleak". After all, that doesn't happen in any other non-software industry
I don't have the knowledge to judge how much of this slowdown is due to the ITER project being international and difficult to manage, and how much of it is due to us approaching the limits of what is physically possible.
However it's good to keep in mind that our level of funding for fusion is pathetic and scientists themselves have categorised it as "fusion never"
I don't think the atoms point is right. Silicon semiconductors are made of atoms. Also, we get Moore's law like behavior in lots of very physical industries, e.g., the cost of solar panels.
A pretty simple model that accounts for the data is that Moore's law, and many other exponential growth examples, require ever larger capital expenditures. This worked for Moore's law because at ever step of improvement the devices produced were highly economically valuable. For fusion, on the other hand, you can have an exponentially improving triple product, but it has zero economic value until you cross the net-positive threshold. That basically means that the exponentially increasing development funding needs to be provided by the government, philanthropy, or some other non-profit source. If you're exponentially improving, with exponential costs, and you hit the ceiling of what the government and philanthropists are willing to provide, your progress can come to an abrupt halt without it necessarily meaning the basic exponential engineering curve you were following stops.
I think the parallel between cost of semiconductor fabs increasing and costs of fusion reactors increasing is quite apt.
But we don't actually have exponential improvement in any physical object, that's not to do with information processing - a solar panel or battery made today is not 10x better than one made 10 years ago.
It's not even true of all semiconductors - power electronics, radio, etc.
> But we don't actually have exponential improvement in any physical object, that's not to do with information processing - a solar panel or battery made today is not 10x better than one made 10 years ago.
Do you understand how differently that reads from your original comment?
> Fusion has advanced faster than Moore's law - and unlike the holy grail of computing, true AI, it's now clearly within reach.
You made the claim it's advancing at a rapid rate and almost here, and when someone pulled up the data it wildly disagreed with you. Now you're just moving the goalposts.
Here's what Robert Zubrin has to say about this graph in his latest book "The case for space" (p174):
"The national fusion programs progressed well during the Cold War because of fierce international competition. They have stopped moving forward in the late 1980s because the decision to consolidate them all into a single global project, the International Thermonuclear Experimental Reactor (ITER), removed all stimulus for action. Indeed, it too, nearly a quarter century for the bureaucrats in charge of ITER to manage to reach a consensus in 2010 on where tu put it, and it will be another quarter century before the machine even attempts to reach thermonuclear ignition in 2035"
That seems like a just-so story to me. It's not like all the smaller fusion research programs stopped existing, the US for example still had the NIF running in parallel, with substantial funding. It's just that it appears that a very large scale project is needed to get above unity fusion with the tocamac approach.
I seem to remember that NIF is focused on nuclear weapons research. Which very likely means that most of the results they produce are highly classified, so of limited usefulness for the rest of the world's scientific community.
Sure that is their main focus but I think they also have a fusion power component in their research. The point was more generally that the inception of ITER did not mean the end of all other smaller fusion research programs, as Zubrin seems to imply.
Judging from the end of this comment chain, the SPARC reactor from Commonwealth Fusion Systems (targeting ignition in 2025) will likely be around the ITER Target on that plot:
Low chance it would have made the Hacker News front page if it did. Unfortunate as it is, the newsworthy component is Bezos's endorsement. Otherwise, it's another fusion start-up.
> it's now clearly within reach that graph ends more than 20 years ago and implies that some important threshold should've been crossed 15 years ago. Did that happen?
To me it seems like an unfortunate but common tactic in marketing-land to seek out any sort of affiliation with a well known brand and to publish it as much as possible.
Very cool. I like that we spend money on alternative routes to fusion. Funding has been so sparse in the last decades that tokamaks essentially sucked up all of it. Maybe other approaches can be built smaller and cheaper.
I think General Fusion's approach is one to keep an eye on. Instead of magnetic confinement, they use pistons to compress liquid metal into which the fuel is injected. The force of the collapsing liquid causes the fuel to fuse, releasing energy which is captured by the metal and then extracted with a heat exchanger.
[i have slightly more than zero knowledge on the matter, what i say might be completely wrong]
There are fast nuclear reactors which use lead-bismuth for the coolant ( the Soviet Alfa class submarine used them to mixed success, but that was in the 80s), so maybe there are alloys with fitting temperature characteristics?
>they use pistons to compress liquid metal into which the fuel is injected.
i wonder whether (and how) they can do it better than the explosive lens of the fission primary. I mean they have to do it better as otherwise there wouldn't be need for the fission primary.
To me, this has an obvious answer - size/weight. A fission primary is in the 50-150kg range, and can spark quite a bit of a fusion secondary at once. How many tons of pistons would you need for the same effect?
i meant the explosive lens of the primary, not the primary itself. The lens is formed by the shock waves of normal explosives moving at 10km/s. We know that that isn't enough to spark the fusion. Thus the question - can their pistons generate the better dynamics than the explosive lens? They have to in order to spark the fusion. If they can - then how?
Yes, in the sense that fusion requires incredibly accurate magnetic fields to maintain, and the second there's any issue with the reactor chamber, the reaction will just stop. The reactor itself cannot explode in any way shape or form, because there is nothing in there to explode. It also doesn't produce any radioactive isotopes while running, it just fuses(hence fusion) hydrogen into helium, just like the sun does. You can just capture this helium and sell it to make baloons if you want.
The reaction itself kicks off a huge amount of neutron radiation, which eventually makes the reactor chamber radioactive - that is the only radioactive waste that will have to be disposed safely eventually. But neither the fuel nor the resulting product are radioactive.
General Fusion's approach doesn't use magnetic confinement. Instead, they use liquid metal and pistons to create the pressures needed for fusion. The liquid metal then absorbs the heat energy which is extracted in the usual way.
What is the sort of lifetime (ball-park) that one might expect before neutron saturation of the reactor walls becomes a serious concern and the reactor has to be scrapped?
You can read about stuff like that in some of the ITER technical reports. They actually want to use that neutron radiation to generate tritium, and feed that back into the reactor.
I don’t think the reactor would be scrapped, just shutdown for maintenance.
The General Fusion design covers the walls with a molten mix of lead and lithium held in place by spinning the chamber. The lithium turns to tritium when you bang on it with a neutron to crease more inputs to the D-T fusion process. And lead doesn't really mind getting hit with neutrons. From the diagrams on Wikipedia[1] it looks like there is some normal metal exposed which might get neutron activated.
Most of the energy that is produced is in the neutrons, so it will be transferred as heat in whatever shield captures the neutrons and which will become radioactive.
So most of the heat will have to be extracted from a radioactive material, with similar precautions like in fission reactors, where the heat is extracted from the radioactive nuclear fuel.
I am very skeptical that fusion of deuterium with tritium or of deuterium with deuterium will ever produce "clean energy", even if they are the easiest fusion reactions, due to the relatively low temperatures required for them.
It still remains to be proven whether the radioactive waste for a fusion reactor of the kinds attempted now will be less than for a fission reactor.
>>It still remains to be proven whether the radioactive waste for a fusion reactor of the kinds attempted now will be less than for a fission reactor.
I wonder, how can this possibly be even a question? Fission based reactors obviously have the same or worse problem of irradiating the entire reactor enclosure and everything around it, so that's at best the same as a fusion reactor + they produce tonnes of very highly radioactive waste that will be radioactive for millennia.
Materials activated through neutron bombardment aren't radioactive for anywhere near as long. And to add to that, nearly all elements produced in a fission reactor are highly toxic in addition to being radioactive - in a fusion reactor if your steel containment chamber becomes activated, you just have radioactive steel, not one of the many many dangerous heavy metals produced through fission.
What you say is true of light water reactors, a 1950s design.
LFTR would be far better. Neutrons breed new fuel, and it consumes virtually all the radioactive fuel with "waste" that rapidly becomes non-dangerous within a month.
So I would guess neutron degradation of the equipment/vessel/reactor will probably be a similar problem in both cases.
The waste really only remains radioactive for a month or so? Not 10k years? Is that just because the other radioactive waste is consumed as fuel, or is that generally true of what it produces?
I'm not a nuclear engineer, but one of the LFTR videos seemed to comprehensively break down the nucleotide chains, and yes the fundamental breeding ability I think helps.
IIRC people have stated that the breeding could also reprocess the bad millenial-scale waste from LWR into usable fuel or other isotopes in MSRs, although maybe not in LFTR.
If we had a decent LFTR industry, we could probably have more specialized MSRs to deal with the "legacy" waste and breeder reprocess into new fuel or other stuff.
The chemists from ORNL seemed pretty amazing. They had all the work done for separating out the byproducts for use in other applications.
Fission is a chain reaction, Fusion is not. A fusion reaction is so unstable that if the reactor failed the conditions for sustaining fusion would immediately stop.
It's basically the hottest plasma we can make suspended in a magnetic donut surrounding by near absolute zero temperatures.
Probably a dumb question, but what are the potential environmental impacts of manufacturing lots of helium? Is it a greenhouse gas? Even if we pivoted to 100% fusion in the next 100 years, is there a chance of releasing enough helium that it would be a problem in practice? I assume we won't need to worry about running out of hydrogen considering all of the water in the world (provided we can efficiently get hydrogen from the more abundant ocean water rather than the limited fresh water)?
Certainly not in the conventional sense (although perhaps there's another way that helium might act similarly to a GHG that I'm not aware of).
Greenhouse gasses are molecules, i.e. multiple atoms bonded together. Those molecules can absorb photons of infrared light, which cause them to vibrate (as if the atoms were held together by springs). After some time, the vibration stops and an infrared photon is emitted.
The problem is: those photons are emitted in a random direction, unrelated to the photon that was absorbed. Half the time they will go roughly upwards, half the time they'll go downwards.
A photon of visible light (from the Sun) can travel down through the atmosphere without interacting much with the greenhouse gasses, since it has too much energy to be absorbed. This visible photon can be absorbed by other materials at ground level, e.g. by a plant, and its energy will eventually result in around 20 lower-energy infrared photons being emitted back up (on average).
These 20 infrared photons are readily absorbed by the greenhouse gasses, and each time they're absorbed, they get re-emitted in a random direction: half the time heading upwards again, but half the time heading back to the ground. This is how energy gets "trapped" by greenhouse gasses.
Helium is almost completely unreactive: it doesn't form molecules in the atmosphere, it just bounces around as individual atoms. Without bonds to vibrate (or asymmetries to spin), the only way it can absorb energy is by speeding up, and even this isn't very effective since its mass is so low. Fast-moving helium is also more likely to escape the Earth's gravity completely.
Hmm. I'd imagine all matter than interacts with photons to be GHGs in some format.
The frequency band for absorption and emission might be different, but the helium could absorb a shorter wavelength, then release a longer wavelength (not infrared) that can be absorbed by something else, then emitted yet again to be infrared
In fact, my understanding is that, not counting nuclear fusion, helium is a non-renewable resource critical for some kinds of critical uses like medicine; and that our current habit of putting it in balloons is considered rather reckless by people taking a longer view of things. If we could capture that helium, it would make things a lot better.
Exactly, helium is likely bound to exhaustion along with natural gases deposits: the only source of helium, currently. It can't be replaced with another gas, at least not in supercoducting magnets, so it's a problem. In the future, fusion power plants will be optimised to reduce helium losses, recycle helium produced by the reactions and may also have to extract helium from the atmosphere. The latter is a rather expensive process given that the concentration is just a few ppm.
Like others have said though - helium escapes our atmosphere naturally and quite literally leaves Earth. That's how we're loosing all of our supply - it's just being vented into space constantly.
Don't worry, even if all energy humans used was from D+T fusion today it would only create 60% of the helium that we use. Also, helium is so light that it leaves the atmosphere so we really don't have access to much anyway.
It's most valuable use is as a cryogenic. If you want sub 10K there are very few materials to choose from.
The lower the temperature, the higher your critical current is for a given superconductor. The reason HTS are a big deal isn't that you can have a superconductor at liquid nitrogen temperatures, but that you can have a very high field at liquid helium temperatures.
Rough estimate, meeting humanity's energy demand (132 PWh per year - that's all energy, not just electricity), with a reasonably efficient fusion station, we'd make 3,000-5,000 tonnes of "waste" helium per year. But as others have alluded to, it's quite a useful element and the general concern is we don't have enough.
Well, technically, that's right. Fusion is a chain reaction. (albeit, "chain" might be a stretch here. Let's say it is a continuous process in stars.) But it's driven by gravity, not neutrons. You just need to bring about 70 times the mass of Jupiter into one place and that's it. Child's play, essentially ;).
The enormous pressure inside stars is what sustains the reaction. Neutrons coming off a fusion reaction, even if moderated, can’t really “squeeze together” other particles in any sense.
Also, per unit volume, the sun produces about as much power as a compost pile.
This lead me to the following - what if you make a compost pile the size (mass) of Sun? Meaning, it won't be made of hydrogen, but rather some carbon-based molecules. I'm not sure about other atoms in these molecules, but I think carbon is stable enough not to initiate nuclear reactions. So probably fusion won't start. What then?
Gravity would compress it. Depending on the exact composition fusion could start, ie it would become a star. According to Wikipedia carbon fusion requires a mass of 8 suns to start but there's a bunch of hydrogen in compost so maybe that would fuse.
No, iirc that statement is for the part of the sun where fusion actually happens. Per volume, not a lot fusions happen in the plasma on the sun. The crux is that the volume of the compost heap grows order cubed to the radius, while the area through which the heat escapes grows quadratic. And the sun is like, a _really_ big compost heap.
In fusion on earth, we want to be considerably more efficient than the fusion process in the sun, as we don't have as much space to work with. ITER is already a pretty big machine.
Fusion can be a chain ration. In stars its caused by intense uninterpreted gravitational pressure. In the H-Bomb its triggered by a smaller fission explosion. Fusion chain reactions just require so much energy its hard (if not impossible) to harness on a commercial level. One small break in the the chain reaction containment and it falls apart.
Which is infinitely better then rapidly overheating and vaporizing and melting the reactor housing and spreading radiation which will stay dangerous for 200 years.
LFTR fission reactions are self-regulating in many ways due to the liquid fuel and thermal expansion abilities, and even if something goes wrong, there is a melt plug that will automatically stop a runaway reaction.
That seems like a faulty explanation. Uncontained fusion is massively energetic and destructive. The device in this article is analogous to an H-bomb weapon with a pneumatic rather than fissile primary.
Fusion bombs are when you put fusible materials next to fission explosions.
Yes, they are massively energetic, (we wouldn't be harvesting power from it if they weren't.) However, they require a very high input energy to trigger the release of the output energy.
With a fission reactor meltdown, the way you get there is by pulling out dampening rods or boiling off all the water, but otherwise leaving the fission rods in the same place.
With a fusion reaction, you have to be constantly providing both the energy to keep the fusion going AND the input material to be fused. Interrupt one or the other and fusion stops.
I know it seems weird that the bigger energy release is safer, but that's how it is. It's the difference between requiring constant input into the system to produce power vs an idle system with no input producing power.
Their explanation is not really faulty. FYI hydrogen bombs are mainly destructive due to fission, not fusion. The fusion step is primarily for bombarding the dangerous fissile fuel with neutrons.
That a fusion bomb has significant energy from fission doesn't seem germane. It still has a great deal of energy from fusion alone.
I'm not trying to scaremonger fusion energy, but I think it's intellectually dishonest to portray is as fundamentally sound, with a binary outcome of either inertia or safe energy. This design relies on spherical compression to both initiate and confine the fusion. We should not discount the possibility that if it instead creates a cylindrical or elliptical confinement due to malfunction, it will just explode, at a minimum destroying the device. We know it is possible to initiate fusion with radial compression in a cylinder, because that's how an H-bomb secondary works.
The main safety factor in these things comes from the fact that a fusion weapon needs hundreds of kilos of hydrogen, and they are experimenting with much smaller masses. That limits the destructive potential.
> but I think it's intellectually dishonest to portray is as fundamentally sound
No offense but I think this sentiment is a huge problem with Hacker News. I have a minimal understanding of fusion energy production from an engineering perspective but I know more than the vast majority of the world due to my background.
You are smart but not a subject matter expert in this topic.
Fusion is not a sustainable a reaction while fission is. Fission happens on its own, fusion requires something else to happen first (on Earth). Please don't insult the people in this thread who are subject matter experts in the field by implying they are intellectually dishonest. I am not a subject matter expert but recognize that a few of them are commenting in this thread with details that I have learned from other experts.
It's not dishonest to portray it as fundamentally sound, because it is. Your argument is that 'If scaled up several orders of magnitude this device could cause dangerous explosions.' This ignores two very important realities:
1) There isn't a reality in which these devices get scaled up to that size.
2) The real danger with fission is radiation, not explosions, which fusion reactors will produce in smaller quantities than a banana farm.
Pure fusion power, even in its largest, most powerful, Elon Musk fever-dream incarnation, is safer than even the safest fission reactor, because there is no way for it to create a boom larger than it's vessel was designed to produce.
Sort of, but it's a vast oversimplification. Fission is very safe relative to something like coal because all of the pollution is concentrated in barrels instead of pushed into the atmosphere, but has the risk of meltdown. To be fair lots of other non-nuclear plants have had disasters that released toxic gasses around the globe too.
Fusion in theory has no pollution at all, but that's theoretical until large scale fusion plants are built.
Fusion reactors don't create fission products, obviously, but why wouldn't fusion create radioactive waste via neutron activation? Materials exposed to neutron flux, in any kind of device, may be activated into radioactive isotopes.
Yes, but first wall materials are chosen to have a high melting point and short half life when activated. Close the building off for 100 years then scrap it. It's a far cry from the myriad of nightmare scenarios fission plants need active control against.
Closing the building off for 100 years might work fine, but that can't be the solution to every problem, it wouldn't be economically viable. Ostensibly simple matters like routine maintenance are very complicated propositions for fusion reactors; you can turn the reactor off but it will still be too radioactive for anybody to work inside. So you either need some sophisticated robotics to repair anything that might ever need repairing, or you have to consider the entire reactor to be disposable.
Of course, repairing things inside a fission reactor is no less nasty, but fission reactors are comparably much simpler and much smaller. Swapping a fission reactor out with a new one is comparably much easier than with a fusion reactor.
For General Fusion, about the only part exposed would be the central column, which I suspect they'll design to be easily replaced; pull out from the top and drop in a new one. Aside from that, the burning plasma is just surrounded by liquid lead/lithium.
MIT's Commonwealth uses an inner wall that's 3D-printed and designed to be replaced annually. They've tested joints in their superconducting tape, which will let them open up the coils on hinges so they can drop in a new inner wall. They'll surround that with liquid beryllium/lithium as coolant and breeding blanket.
Basically yes. Both fission reactors and fusion reactors generate a bunch of neutrons.
With a fission reactor you have to expose uranium to those neutrons and when it gets hit it either splits into dangerously radioactive components or absorbs a neutron and becomes dangerously radioactive plutonium. There are pipes and stuff that become a bit radioactive too but that's not the part that people are afraid of when an accident happens. Also, the dangerously radioactive byproducts continue to release a lot of energy after the chain reaction is shut down, about 10% of the power the reactor was run at. So even after a fission reactor is shut down you need to keep cooling it otherwise things melt and people become unhappy.
With fusion you do need to keep exposing lithium to the neutrons from the reaction to make more tritium fuel. And tritium is radioactive. But if it escapes it'll go straight up into the upper atmosphere where it won't particularly bother people and then dilute. You've still got the radioactive pipes problem you do with fission but, again, that's not really the part that people are afraid of. And once you stop containing the plasma energy generation stops instantly.
I'm generally inclined to say that the risks involved in fission are worth the benefits but those risks are worth taking seriously and require careful government regulation more so than other forms of power. With fusion, on the other hand, I'd a lot less concerned with someone building a power plant up wind of me than a coal plant even with similar levels of regulation. Just as long as they aren't deliberately exposing uranium to the neutrons or something like that.
Fusion byproducts are by and large significantly safer than fission.
Fission byproducts are well known to just be a ton of heavy metal junk that decays over thousands of years.
I'm sure there's fusion byproducts that are nasty too, but fundamentally you can't get byproducts as high up on the elemental chart as you can with fission strictly because fusion is merging 2 smaller atoms into 1 larger atom. With fission you start with a larger atom and break it into 2 smaller ones. Oversimplified, but you get the idea.
Given that the US has only 1 reactor that was commercially put into operation after 1990s [1], it's a pretty realistic way to look at it in the US.
Newer reactors and spent fuel reprocessing are definitely ways to solve the issue, but the fact is you still create those nasty byproducts in the traditional reactors today.
It's not air pressure, it's a shock wave in liquid metal.
The BBC article is simplified a bit too far for anyone with a technical background but I doubt if a more accurate version would be much more meaningful to most people.
2. Description of the Related Art Various systems for heating and compressing plasmas to high temperatures and densities have been described. One approach for accomplishing plasma heating and compression by spherical focusing of a large amplitude acoustic pressure wave in a liquid medium is described in U.S. Patent Publica tion No. 2006/0198486, published Sep. 7, 2006, entitled “Pressure Wave Generator and Controller for Generating a Pressure Wave in a Fusion Reactor”, which is hereby incor porated by reference herein in its entirety. In certain embodi ments of this approach, a plurality of pistons is arranged around a substantially spherical vessel containing a liquid medium. A vortex or cavity is created in the liquid medium. The pistons are accelerated and strike the outer wall of the vessel generating an acoustic wave. The acoustic wave generated in the liquid medium converges and envelopes a plasma that is introduced into the Vortex, thereby heating and compressing the plasma.
It's a question of relative scale. If you have big enough pistons squeezing a small/light enough amount of plasma then you could make the pressure work.
It's great to see non-tokamak designs being developed
I have no idea how much compression they get, but I do know they're targeting a middle range between magnetic fusion (low density, long confinement) and inertial fusion (high density, short confinement).
They mention steam in their demo video drives the primary pistons, which in turn drives a 2nd set of pistons that contour a liquid metal chamber, which in turn compresses the fuel mixture.
In the original General Fusion plan: Pneumatic pistons which strike anvils in the chamber wall creating a shockwave which implodes the liquid wall with fusion-igniting pressures.
I think they may have moved away from that in favor of big pneumatic pistons pushing tiny piston heads directly into the liquid though. Mechanical advantage is the area ratio, which you can easily make quite large.
The liquid metal is mostly lead which has a fairly low melting point so doesn’t need anything exotic. Melting point is 327.5°C which you easily can reach on a stovetop for comparison https://www.google.com/search?q=maximum+temperature+stovetop
For the same reason a jug of water poured on a lit match doesn’t vaporise: the thermal mass of the lead is enough to absorb the heat produced by the fusion.
It takes about one second for 1 megawatt to boil three litres of water.
The pulsed fusion system will produce a huge peak power output but only for an extremely short time. They design the system so that the total heat output is absorbed by the lead mass. The other constraint is the lead needs to be thick enough to absorb the vast majority of the radioactive particles before they reach the machine.
“Compressed Gas Driver: Using practical, existing technology, steam powered pistons compress the plasma to fusion conditions. Not requiring the exotic lasers or giant magnets found in other fusion approaches, steam pistons can be practically implemented in a commercial power plant.”. From https://generalfusion.com/technology-magnetized-target-fusio...
It's a shockwave through molten metal. It's a very interesting technique called magnetized target fusion that has been described as a "thermonuclear diesel engine."
It is no coincidence. If everything goes to plan, ITER will demonstrate first plasma in 2025, which will be a bit of a PR nightmare for ITER (as it will not have high Q's, and go out of operation for another 10 years after that).
So a lot of alternatives, like SPARC, General Fusion, Lockheed, Tokamak Energy, Commonwealth Fusion, ... are all aiming to demonstrate in 2025 as well, because it will contrast nicely to the ITER approach costing a lot of government money. Anyone that will beat the Q of iter in 2025, might see more government funding flowing their way between 2025 and 2035, because they managed to do the same, but orders of magnitude cheaper.
Well, yes? All of them will try to show a brothers Wright moment of science history in 2025 (except ITER, which will do more like a sanity check). But building commercial airlines is the step after that and will need more funding and research.
Commercially viable fusion is not for before 2045, but its MVP might be there in 2025, if one is really optimistic.
Not in 2025, except if ITER would have a huge unforeseen failure mode. ITER will have good data in 2035.
ITER is mostly a giant experiment in programme management. One could argue that it is the most complex machine built so far by humanity, way more complex than e.g. the LHC or Ligo or ISS. 2025 might give us an upperbound on the complexity of machines humanity can manage with our current society.
Haha. As someone who works deeply in the energy industry timelines and scope creep always happen. Sales/project development is so aggressive on timelines and the unknown unknown pretty much always blow up timelines. That and regulatory issues. Chances of Fusion delivering in 2025 is pretty low but I appreciate the optimism. Downvote away with your rose colored glasses.
We could build the optically-coupled ground stations for the gravity-confined fusion power source around which our planet orbits at a small cost and within a few years.
My understanding is that we cannot scale that to meet our electricity needs, and we need to keep the lights on when it is dark outside. Due to this, solar isn't good enough. ( Though should certainly be part of the plan. )
The sun is always shining somewhere on earth, so maybe it's possible [1] to connect all our grids together and transmit power from the light side to the dark side. Whether this is cheaper than buffering the power in huge energy storage systems, I have no idea.
The Sun is a self-sustaining fusion plasma that already exists. It is confined by its own gravity. It will continue running at a steady state for billions of years. Except for melanomas, this source of power is completely harmless to human life.
In order to plug this thing into the electric grid, all we need to do is capture the free electromagnetic emissions of the Sun. We already have this technology, called a photovoltaic cell. The production of such cells is an industrial engineering problem. There are no technological barriers.
Compare to "fusion power", for which the ignition, confinement, and exploitation of the energy are all totally unsolved technological problems.
Are they any faster to build than fission reactors? If not, we can as well start building fission reactors instead of having to get the technology right and then to build them. (If you insist on a type of nuclear power.)
TLDR: Despite recent progress, is it possible that fusion will reach efficiency where it is net positive in energy output but still too expensive to be useful?
Long Version: When I first heard about fusion, the idea was that this immense energy could be harvested taking advantage the the conversion of matter into energy. Everything I heard was that the quantities are so great that if we could just nail the sustained fusion reaction we could harvest potentially limitless energy.
As I've come to understand it however, it is not so simple. The big question is in how long you can sustain the reaction and how much energy it costs to start it in the first place. It seems to me the strides that have been made over the last few decades are to bring the cost down enough and extend the reaction long enough that the net energy loss is lower, then break even and now possibly a net gain. I've seen some articles imply that this turn of events means fusion is definitely on the table as a near future abundant energy source.
My question is this. Is it a forgone conclusion that the current trends will continue? Because if not, doesn't that mean fusion could still get stuck somewhere where there is a net energy gain but it's still too expensive to be useful?
The first generation of fusion reactors will be expensive and monolithic, but we will learn a lot from them and it will prove their fundamental functionality.
The second generation reactors will likely be using better fuels and squeezing plasma into different shapes to keep them running as long as possible.
Even if other renewable energy sources continue to get cheaper and become prolific, they still have the problem of energy storage. Simply put, we don't have anywhere near the resources required to build all that storage. So what we need instead is a solid mainline energy source (nuclear and fusion).
In the case of a massive breakthrough in energy storage, at best it will just delay fusion power. We will still need to use fusion off planet.
"we don't have anywhere near the resources required to build all that storage."
Sources?
There are lithiumfree batteries, made from cheap metals. Saltwater batteries for example.
Airpressure as energy storage.
Hydrogen or more processed into methanol ....
Etc., etc. all working technology as of today.
And sure, sure, storage comes with lower efficency, but there is no reason, we cannot transform the various deserts into big solarplants.
Fusion would be awesome to have. But I see no indication, that it will be ready anytime soon, when we need it, to produce clean energy at scale. And if it is ready, we probably still need resources, like Helium-3. Ready to mine the moon?
I don't expect building a fusion power plant to become cheaper than a gas power plant. Both need steam turbines, cooling pipes, a big building, etc.. So that would be a lower bound on the construction cost.
If solar+batteries can outcompete fossil fuel plants (while ignoring fuel costs), then fusion likely wouldn't be viable commercially. And if you look at [the data](https://en.wikipedia.org/wiki/Cost_of_electricity_by_source#...), we are already close to this point.
"Despite recent progress, is it possible that fusion will reach efficiency where it is net positive in energy output but still too expensive to be useful"
This is very likely and expected. First we need that positive output - then we can improve and scale up .. and then it might be worth it.
Keep an ear out for ITER doing exactly that in 10-15 years. First plasma in 5.
ITER was designed with LTS coils and will cost in the range of 50 billion USD. HTS coils are a big deal for driving size and cost down. MCF is still the king in terms of fewest engineering hurdles to overcome. Mirrors and liquid metal pistons are certainly neat avenues and should be explored, but you won't see them in 1st generation plants.
Do you think some of the projects currently in development which are for teating but not useful efficiancy like ITER might later be retrofitted with bwtter technology which could make them efficient enough for utility?
The important sentence: "It won't generate power".
It's all fine to do this as a research project. But this is not a technology that is going to solve our energy problems any time soon - and it certainly shouldn't distract from deploying the solutions that exist today, aka mostly wind+solar.
They don't know exactly how to build a commercial reactor yet. The scale they've worked at so far tests the basic design but it can't break even (no fusion reactor has yet) or function continuously. They are going to build the minimum size that they think will achieve these goals but it will also have to be capable of testing to be able to fine tune operation. A commercial reactor wouldn't be built like that.
Also, keep in mind that cost doesn't scale linearly. Likely cost goes up with the cube of the size or higher.
US private investment - more opportunity for fusion reactors in US if progress is indeed proved out. Collab between the two does justify the reason though.
I would rather have UK gov invest in the company than "subsidise" - it is not clear why it is fair to subsidise this company as opposed to other start-ups in this space.
He funds Blue Origin to the tune of a billion USD a year, and he is scheduled to take the first commercial flight on BO's New Separd in July. I doubt he is bored. He also funds Bezos Earth Fund, if you're curious what else he is up to once he steps down from running Amazon.
I agree, if capitalism and the free market is to produce individuals who have fuck-you-money^2 then it would be great if they did interesting/innovative things that the market as a collective may pass on as being too risky and/or researchers can't get the funding for bc there's not enough money or the grant seems too risky.
If Bezos is paying for it, then by definition the market is investing in it. Unless you think Bezos's money exists somehow outside of the market.
When I invest in an ice cream cone, that ice cream is about to be destroyed and my investment will soon be down the toilet, but I was certainly participating in the market. If Bezos's reactor blows up, it will be little bits of the free market raining down. And if it powers the world with endless green energy, there will be little green energy free market electrons pumped across the world.
I honestly don't understand why there's so much focus on fusion. It's an inferior method of producing energy - extremely fussy, still produces nuclear waste, still capable of producing nuclear weapons material, and has yet to deliver a net surplus of energy[1]. When I was younger I never saw a peep about the nuclear waste and nuclear proliferation problems with fusion - it was just pitched as this miracle technology that was ten years away. I was really excited about it, but the more I learn about fusion the more it appears to be a giant money bonfire.
We'd be better off just coming up with good fast breeder reactor designs that have good safety measures. A breeder reactor can burn its fuel completely, it's a tried and true technology and it's our best shot at eliminating fossil fuels.
The fusion research is important science, and I completely support researching it, but it's not a technology that's going to be commercially useful in our lifetimes and it's not better or cleaner technology than modern fission reactor designs.
We already have fusion bombs. Building fusion reactors wouldn't impact nuclear proliferation at all. I really can't think of a single fusion reactor design that produces "nuclear weapons material." If fusion designs made nuclear material, then we'd probably already have nuclear-material-producing fusion reactors.
I find it strange that you think breeder reactors are the way to go. Fusion's challenges are rooted in engineering - creating magnetic fields, heating plasma, breeding tritium. Fission's challenges are in public sentiment, exuberant costs, and dealing with extremely toxic metals.
> it's not better or cleaner technology than modern fission reactor designs
The "nasty ingredients" in fusion are deuterium, tritium, lithium, and irradiated confinement metal (think eutectic materials like stainless steel). The "nasty ingredients" for fission are much, much worse - both in products and required inputs.
Fusion promises energy generation without the high atomic count; this makes the inputs easier to acquire, the risk of catastrophe much lower, and allows more flexibility in design (scale, cost, efficiency targets).
> Building fusion reactors wouldn't impact nuclear proliferation at all. I really can't think of a single fusion reactor design that produces "nuclear weapons material."
Since a fusion reactor would produce an intense neutron field, it doesn't take a genius to figure out that if you line the reactor vessel with natural uranium, you have a device for producing plutonium. That is by no means a showstopper, but it means fusion plants will need 24/7 security, IAEA inspections, worries when/if suspicious tinpot dictator states decide that they will need their own fusion power plants, etc. etc. Even if we'd magically solve the technical challenges in fusion, we won't be seeing things like dinky fusion-powered ships sailing around the oceans (for larger ships, one could envision some kind of IAEA monitoring system for those).
Of course, if someone figures out aneutronic fusion (pB11 or such), these proliferation concerns would evaporate. That's a pretty big if, though.
> dealing with extremely toxic metals.
Spent fuel, in particular, is certainly radiotoxic, but chemically, no, not that big of a worry. Society routinely deals with other toxic heavy metals like lead as well, not to mention all kinds of other extremely toxic compounds.
Fusion power plants are certainly not the only thing we have that makes neutrons. You can buy neutron sources suitable for irradiating fissile material without having to build a fusion power plant.
Fusion power plants would also be a terrible place to irradiate uranium. Getting material in and out would be a total hassle and you wouldn't necessarily be able to control the reaction.
> Fission's challenges are in public sentiment, exuberant costs, and dealing with extremely toxic metals.
I'd argue that a lot of the public sentiment problems with nuclear were PR'd into existence by the insanely powerful and wealthy fossil fuel industry to which fission is a very real existential threat. If we're talking about exuberant costs, fusion beats fusion hands down and has yet to deliver a single net watt of power. The waste disposal is more of a political problem than a technical one.
Overall, the problems with fusion are hard technical problems, and the problems with fission are self-imposed political ones pushed by the fossil fuel extraction industry that fission could very realistically replace.
While it would last a long time at current levels, the supply of fission materials is quite limited when you’re looking into interstellar travel etc. That’s really the promise of fusion it’s an unimaginably vast energy source for the future.
As to more sort term concerns, fission has a lot of very expensive requirements like 24/7/365 security which make it difficult to integrate with vastly cheaper renewables. Baseline power sources like nuclear and coal wind are at a massive disadvantage when integrating with significantly cheaper wind and solar. They lose significant amounts of money during part of the day and need much higher premiums the rest of the day to make up for it.
In today’s energy market there is definitely a place for fission. However, with a 50 year payback period you need to project into future energy markers with even cheaper solar, wind, and batteries. That’s why electricity companies generally view it as a dead end. Fusion is a larger unknown, it’s probably not going to be cost effective but it’s also the kind of long shot that might just pay off.
> the supply of fission materials is quite limited when you’re looking into interstellar travel etc
Yeah, sure, if we're gonna get a big spaceship to even a small fraction of light speed, that would require absolutely stupendous amounts of energy.
But lets worry about that after we avoid cooking ourselves with GHG emissions? We might or might not have enough fission fuel for large-scale interstellar travel, but certainly more than enough to get rid of fossil fuels.
> fission has a lot of very expensive requirements like 24/7/365 security
So will fusion, unfortunately, unless someone figures out aneutronic fusion, which is a much longer shot than D-T fusion most efforts are concentrating on.
I'm all for spending a lot more on fusion R&D though; the potential win is just so enormously large that it makes sense to bet some amount of resources on it, just in case it works out.
Unfortunately, we live in a world where public opinion (skewed by fossil fuel companies or otherwise) is a huge driving force. We can lament what the world would be like if only people were more knowledgeable, but at the end of the day it's the ecosystem we have to operate in.
Fusion power has indeed had high R&D costs, but so has any significant project before the ROI starts to kick in. Fusion power (especially the types that don't generate a neutron flux) is safer and more productive in principle compared to fission, and I have high confidence I will live to see a commercial fusion reactor come online in my lifetime.
It's a pretty big logical jump to say fusion has proliferation problem because it creates a neutron stream. It will be as if they build the Hadron collider to warm up soup. It's unrelated to the plant operation, unlike fission.
I think this highlights the bias in the article you shared. Moreover, it solely focuses on ITER which is not a great example any more.
Fusion doesn't really have the problems of fission. Because fusion has been extremely underfunded, the money is being spent extra carefully on ITER. But MIT SPARC is using new super conductors to get much smaller reactors.
Reactors will produce some low level waste, but once we get a handle of the confinement, that issue can be eliminated with hydrogen isotope mixes. Also, Tokamak is only one fusion design, there may be better ways to capture the neutron stream.
These are all valid points, and I'm not saying we shouldn't do research on fusion. It certainly has promise. However, I don't think it has a serious chance of pulling a deus ex machina move and saving us from climate change in our lifetimes. A solid energy source a century from now? Sure. Fission on the other hand has a good chance of uprooting the fossil fuel industry, and combined with other renewables is our best chance of getting carbon emissions to a place where civilization might not go into a bronze age-style collapse from climate change.
As an industry insider: everyone knows this. Fusion isn't the technology that saves mankind in this century, but it is the technology that mankind needs to have working by the next century if we want to stay on our current industrial track. The march of progress might halt if we run out of ever-increasing access to free energy.
Yes but you only have to worry about radioactive reactor parts and other structural materials, not spent fuel.
> still capable of producing nuclear weapons material,
I don't get this argument at all. A fusion reactor does not generate heavy elements such as uranium or plutonium. However, the fusion reaction can be a neutron source which could be used to convert heavy elements such as thorium or uranium into fissile material. But by no means would this be part of any power generation station. This leads us to...
> We'd be better off just coming up with good fast breeder reactor designs
So this neutron source is somehow more clean and secure than the other one you just dismissed?
Working on fusion doesn't mean we're not working on better fission. We should do both. I think both fusion/fission are great but your comment is misleading at best.
- Fusion produces much less radioactive waste byproducts then fission. It's not zero, but it's a significant difference.
- The problems with nuclear weapons proliferation are much easier to handle with fusion. For starters, you're not transporting enriched uranium fuel around. Also you don't end up with fun transuranics like plutonium which can be readily used to make weapons, unlike any key byproducts of fusion. Hell, the main byproduct of our fusion reactors is gonna be Helium, which we actually need more of because it is a very useful element that experiences shortages due to not being contained in the atmosphere and not being super prevalent in the earth's crust.
- "Extremely fussy" is a selling point. Extremely fussy means that if something goes wrong you don't have a runaway chain reaction that makes everything go boom. It's impossible to design a fusion reactor that can melt down. Meanwhile, melting down is the default mode for fission reactors and needs to be carefully designed around.
- Fusion is the only viable energy source for long-term space travel/colonization.
- The point about net energy surplus is kinda nonsensical. Of course we're not there yet, that's why it's a problem we're actively working on and not something we've already solved. Your point is literally "we shouldn't develop this technology because we haven't developed this technology yet".
Also not sure how we can simultaneously need to "come up" with a good fast breeder reactor design while at the same time it's apparently "tried and true technology".
> - "Extremely fussy" is a selling point. Extremely fussy means that if something goes wrong you don't have a runaway chain reaction that makes everything go boom.
Sorry, I should've elaborated a bit on this point. I'm talking about the expensive containment system which will be subject to extreme conditions and have a short lifetime[1].
> Under reactor-relevant conditions, the following are the most serious damaging mechanisms: thermally induced defects such as cracking and melting of the plasma-facing material (PFM); thermal fatigue damage of the joints between the PFM and the heat sink; hydrogen-induced blistering; helium-generated formation of nanosized clusters; and neutron-induced degradation of the wall armor via reduction of the thermal conductivity, embrittlement, transmutation, and activation.
> Further serious lifetime-limiting PWI processes are caused by material irradiation with hydrogen isotope ions (D+ and T+) and impurities that—depending on their impact energy—will sputter the wall material. The eroded species will be deposited elsewhere, for example, on unshielded parts of the vacuum vessel, on blanket modules, or on less severely exposed divertor targets (outside the separatrix strike zone). Implantation of hydrogen isotopes into the surface of the PFM will result in severe embrittlement of the wall. This also has a strong impact on its cracking resistance, in particular during short transient thermal loads (i.e., ELMs). Helium will also be implanted into the surface of the wall armor or buried in redeposited surface layers. Implanted helium tends to migrate (depending on the prevailing temperature) and to form tiny bubbles that again can interact with implanted hydrogen. In several fusion-relevant PFMs (e.g., tungsten) helium can initiate rather substantial changes in surface morphology, such as the growth of tiny tendrils or “fuzz” on the surface of the PFM.12 These layers can easily reach several micrometers in thickness. These effects need to be considered as a potential source for the release of dust particles and contamination of the burning fusion plasma.
So I'm not talking about the fail-safe nature but rather the extreme cost and technical difficulty of containing the reaction for the amount of time that would be needed for fusion to be a viable commercial energy source.
I think one of the advantages of the General Fusion approach is that both what the heat gets transferred to and what bears most of the neutron flux (and hence gets irradiated) is the liquid metal, which is presumably easily replaced (and could presumably even be done incrementally while the reactor is live, since it's going to be flowing through a heat exchanger anyway)?
Massachusetts, in the Northeast, is showing a real-world strategy for solar.
Massachusetts incentivizes homeowners to have their own solar installs. My house, for example, has solar, as do many houses in my town. Yesterday it produced about 50 kWh, meaning I was sending energy into the grid.
You might ask, what's the point of solar if there's no storage? Going 100% renewable would be amazing, but reducing CO2 is a win. If electric load declines because more and more homes can produce their own electric, that's a huge reduction in total CO2 that needs to be produced at the power plants. It doesn't mean we can throw away the gas plants, but they can be run at lower capacity. Storage isn't really discussed yet, but maybe one day we'll get there.
We're also investing in a huge offshore wind farm.
We definitely do! However the rate that solar can be added is nowhere near fast enough to replace fossil fuels in a timeframe that meets our climate goals and prevents environmental catastrophe[1].
> Solar and wind power alone can’t scale up fast enough to generate the vast amounts of electricity that will be needed by midcentury, especially as we convert car engines and the like from fossil fuels to carbon-free energy sources. Even Germany’s concerted recent effort to add renewables—the most ambitious national effort so far—was nowhere near fast enough. A global increase in renewables at a rate matching Germany’s peak success would add about 0.7 trillion kilowatt-hours of clean electricity every year. That’s just over a fifth of the necessary 3.3 trillion annual target.
> To put it another way, even if the world were as enthusiastic and technically capable as Germany at the height of its renewables buildup—and neither of these is even close to true in the great majority of countries—decarbonizing the world at that rate would take nearly 150 years.
Between 2010 and 2019 the UK added 10GW of onshore wind generating capacity, 8.5GW of offshore wind generating capacity, roughly 13GW of solar capacity, and 0 nuclear plants.
The UK has not brought a new (commercial/public power) nuclear reactor online since the nineties, or finished building a completely new site since the eighties.
It has started building one, which is over budget and delayed and has been described as “the most expensive power station in the world”.
It has had three recent plans cancelled, four more go nowhere in years, had two developers (EON and nPower) pull out of UK nuclear, and the Scottish parliament had backed no new nuclear plants in Scotland.
If nuclear is our saviour, it’s not looking very likely that we’ll be saved.
It seems unfair to compare a hypothetical nuclear build rate to a real one in renewables. We just don't know if a nuclear industry could get anywhere near the deployment rate required.
You're right, and I'm not saying we should slow down on solar, but based on the numbers, solar alone is not going to get us where we need to be, so we should be pushing the nuclear industry to find out how fast they can deploy and bulldozing a path for them while we also push for faster deployment of solar.
Perspective given in the article belittles great strides made by fusion pioneers and poisons discussion on public policy:
Fusion has advanced faster than Moore's law - and unlike the holy grail of computing, true AI, it's now clearly within reach. https://www.reddit.com/r/pics/comments/hsmge/moores_law_for_...
>"Frustrated by the slow progress, private companies [innovate]"
This is not about frustration, it's about opportunity:
After decades and billions spent on research and engineering, all "open source", and training a generation of plasma scientists, venture capital can hire these people into profitable ventures. I'd like to ensure these people are given proper credit, and actually make some money off their great contribution to humanity.
I fear that all we will do to reward greatest minds is give them mediocre jobs.