As a newbie in nuclear fusion, this explanation is the most interesting part:
> Lee Margetts at the University of Manchester, UK, says that the physics of fusion reactors is becoming well understood, but that there are technical hurdles to overcome before a working power plant can be built. Part of that will be developing methods to withdraw heat from the reactor and use it to generate electrical current.
> “It’s not physics, it’s engineering,” he says. “If you just think about this from the point of view of a gas-fired or a coal-fired power station, if you didn’t have anything to take the heat away, then the people operating it would say ‘we have to switch it off because it gets too hot and it will melt the power station’, and that’s exactly the situation here.”
When I was at school in Abingdon, Oxfordshire (UK) around 1988 my physics class (A level aged 17) was somewhat enlivened by a visit by a bunch of clever chaps from JET at the Culham labs from up the road.
This was the first time I heard the "nuclear fusion is 25 years away" joke and it was told as such. We were also shown a graph of how many orders of magnitude away from ignition (for want of the correct word) by date. It had an initial steep decline but then turned right quite sharply and had annoying looking tendency to avoid the magic value.
Now, once you have ignition, you have to sustain it and extract power from it. That's quite tricky too!
We were also shown a graph of how many orders of magnitude away from ignition (for want of the correct word) by date
See p.4-5 of [1] for more recent plots. It includes earlier runs of both KSTAR (the experiment under discussion) and EAST (the Chinese one mentioned in another comment), but not their most recent ones.
It's interesting to see that South Korea has such strong nuclear research facilities. Taiwan lost a lot of nuclear researchers in the past decades. Some of it due to US lobby work and some of it due to stupid governmental policies in the recent past. Japan which is also quite strong in nuclear seems to be trying to sell part of their nuclear industry, a move which turned out disastrously for the french.
> “This team is finding that the density confinement is actually a bit lower than traditional operating modes, which is not necessarily a bad thing, because it’s compensated for by higher temperatures in the core,” he says. “It’s definitely exciting, but there’s a big uncertainty about how well our understanding of the physics scales to larger devices. So something like ITER is going to be much bigger than KSTAR”.
This made me wonder when ITER was going to actually be up and running. From wikipedia:
> "The reactor was expected to take 10 years to build and ITER had planned to test its first plasma in 2020 and achieve full fusion by 2023, however the schedule is now to test first plasma in 2025 and full fusion in 2035."
So, it sounds like it'll start doing something within a few years, but it'll probably be a long time before it produces significant scientific results.
By the time ITER is running, maybe some other group will beat them to it (like the MIT ARC or SPARC reactors, which use more recent, better superconductors and don't need to be anywhere near as big).
"While the duration and temperature alone aren’t records, the simultaneous achievement of heat and stability brings us a step closer to a viable fusion reactor – as long as the technique used can be scaled up."
Half of the engineers on HN right now:
[...as long as the technique used can be scaled up...](PTSD_Chihuahua.jpg)
I don't know everything about nuclear fusion so I have to ask: Is it actually renewable?
In other words, are the byproducts able to form back into the "fuel" at a reasonable rate with the energy input of the Sun? I know that a selling point of fusion is that there is such an abundance of fuel that this doesn't matter. But if we treat finite energy sources as infinite, exponential growth in our energy budget means that we will undoubtedly run out of energy, as is being done with forests and such.
After all, I have a feeling people at the dawn of the industrial revolution thought the amount of coal available in the world would serve their needs "practically forever," until energy consumption scaled up by thousands of times.
So, the fusion we are talking about here is deuterium - tritium fusion as it should be the easiest to achieve. Deuterium is not a problem. A rough estimate says that there's enough of the stuff to cover 100% of the world needs for thousands of years. And it's easy to breed: surround the reactor with water so the hydrogen there can capture the stray neutrons.
Tritium, on the other hand, is a problem. It is radioactive with a half life of ~12 years and so the little we have needs to be produced since we can't really accumulate it. Currently it is produced by conventional nuclear reactors. Additionally, breeding tritium is harder than deuterium and requires a blanket around the reactor that uses other materials to multiply the number of stray neutrons. For each atom of Tritium that is fused we could get somewhere between 1.1 to 1.7 with a theoretical maximum of 2 Tritium atoms so, finally answering your question, it is renewable. It's just hard, but a piece of cake compared to actually maintaining a stable fusion.
Ultimately, no method of energy generation is truly renewable, including solar. The Sun will run out of fuel in five billion years, after all, give or take.
However, for all practical intents and purposes, solar energy is renewable. The same holds true for nuclear fusion for at least a couple of hundred years, even considering growing energy consumption.
Deuterium fuel is the most abundant. There's enough in your morning shower to supply all your energy needs for a year. There's enough in the oceans to last for billions of years. Fusion is as close to renewable as anything, because it'll last until the sun goes out.
Right now most projects are also using tritium fuel, which has to be made from lithium. That's plenty abundant but not to the extreme of deuterium. But pure deuterium fusion is possible, just a little harder. And one prominent fusion startup, Helion, is actually using deuterium (along with helium-3, which is the waste product of deuterium fusion).
By the point we've fused significant portion of Earths hydrogen, it will really not be a problem to hop over to Jupiter for some more. The scales are insane. Energy input of the Sun ALSO isn't renewable if you think like this.
People talking about fusion expect to "breed" tritium in their reactor. This takes the form of blasting GW of hot neutrons into a thousand (or ten-) tons of lithium hydroxide, and somehow extracting grams of tritium from it at parts-per-billion concentration.
There is no choice about that: it is the only way to get enough tritium to keep operating.
I completely support fusion efforts from a science point of view, but let's be honest, an economic reactor for electricity generation is still decades away, it may not even be feasible, and it certainly won't be as 'clean' as is being sold, using D-T fusion.
We should switch a good chunk of fussion funding towards 'clean' fission; travelling wave reactors, molten salt, small modular reactors, thorium, etc, etc. Some of these have a chance at being commercially viable and making a real impact this decade, not half a century or more hence.
You can iterate the argument one step further and say that affordable nuclear is too far into the future, and that we should instead focus on more immediately realizable options such as wind, solar, geothermal etc.
This is where much of the energy debate in Europe is at now. It is exactly the same argument being used against fission.
Pick any technology that has come to fruition in the last decade. Video streaming as a substitute for cable and terrestrial TV. Mass adoption of Smart Phones. EVs becoming a viable option for broad populations of car owners. A space startup that came from nowhere and rapidly out-competed the incumbents. All of them.
Remember the Apollo astronauts who walked on the moon shitting on private space companies on C-SPAN not that many years ago?
Look at the time span between people dismissing these technologies as off in the distant future and when they arrived. People have a tendency to assume that tomorrow will be the same as today.
Affordable nuclear is still some years away. I think the events in Europe actually shortened that distance into the future by a significant amount just in the last 6 months. But fission power is still "too slow". Fusion is even more years away into the future. If/When it comes to fruition people are going to be surprised, and none more so than the experts.
Because the experts are almost always wrong for a good while after disruptive breakthroughs have already happened.
It means we have to think ahead and make sufficient bets on technologies that exist at all time scales. And the more potential they have for delivering stable base load, the higher the payoff.
Yes we have to invest in both fission and fusion. And we have to invest a lot more than we already do.
We have dozens of fusion startups, and dozens of fission startups working on everything you suggested. The fusion startups build test reactors. The fission startups do paper reactors and license applications, and in the US at least, if it's not a water-cooled solid uranium reactor, they probably won't get any further.
Fix the NRC, and we might get somewhere with fission.
Or just make more old style fission reactors and deregulate. Even an accident every decade would be well worth it if it got costs back down to what they were in the 70s (adjusted for inflation), in that the money saved could be invested into healthcare with far better returns than we're getting on nuclear safety.
Correct me if I’m wrong, but wouldn’t a huge amount of released energy in this scale eventually heat up the planet?
I mean, doesn’t the atmosphere in our big greenhouse always retains a non-zero amount of energy, no matter the CO2 etc. in the air? If that is true, then so far the net energy out flux was positive, but now we see with rising greenhouse concentrations that it’s turning. If we then raise the stock of energy inside the greenhouse, it overheats, no?
Climate change has inertia so probably not solved by the time we have industrial scale fusion + would not solve the two other main anthropic activity related problems: biodiversity loss and depletion of natural resources
Little effect I think. Fusion power can do little that fission power can't do already, which is provide "free" power after you look past the cost to build and maintain the plant. The best advantage of fusion power is the public perception is presently better.
Long term, yes. But much of the climate change problem is decided in the next 25 years. Even if this reactor would work right now, building enough of them in that time frame everywhere, switching all industry and factories to electric, switching all transportation and cars and heating systems in all the houses to electric is very tough.
Climate change not solved. This is another in our long series of silver bullets.
Greenhouse gases retain heat. Sea level temperature is a function of ambient heat due to sunlight and other heat sources, minus the rate at which it dissipates into outer space, mediated by the insulation effect of the atmosphere.
Projects that try to reduce the carbon intensity of energy are focused on changing the denominator in the equation. The current aim of these projects is to produce a cheap and plentiful energy source, via a heat engine. What they are actually chasing, whether they admit it to themselves or not, is a cheap and plentiful heat source. If they succeed they change both the numerator and the denominator, which ends up partially cancelling each other.
Wind and solar are different because they tap into an existing heat engine, instead of trying to build a new one.
What we as a people need is a fusion plant that costs less per KWH than a fossil fuel power plant with tariffs to account for the cost of the carbon dioxide, but still about as expensive as a fossil fuel plant where the carbon is free. If we actually got a fusion plant that was 10x more cost efficient then we'll just introduce the concept of heat pollution to the conversation, swapping out the villain in the story but keeping the same outcome.
Idk. If you want a steady stream of energy enough to power a small house, you can achieve that for $20k today with a big enough solar panel and a PowerWall. Fusion has to be cheap as well as effective.
> What effect would it have on humanity? Climate change is solved.
Not really. It'll just be another tool for the fossil fuel lobby to use to misdirect attention from what will make them irrelevant forever (reduction and sunlight).
Even if the reactor part is free and 100% reliable. Getting heat out of a 100 million degree chamber that is spewing neutrons everywhere and turning it into electricity is much much harder and more expensive than collecting some photons and building a train.
We already have proven basically unlimited electric energy in the form of PV panels (and batteries if you need it stored). So far, that tech has not solved climate change at all, because actually building enough of these things is something that people need to be willing to pay for.
Each dollar diverted to this from building out renewables brings climate disaster, global civilization collapse, and billions starving, incrementally nearer.
It might solve the greenhouse side of climate change, but you can't run away from thermodynamics. All electricity generated eventually turns into heat. Earth can only radiate so much heat into space in a given time period. If you generate more heat than Earth is capable of radiating, the planet warms. Don't start thinking that "free energy" from fusion reactors means that we can generate infinite power (as nice as that would be). It just means that the new negative externality would be heat itself.
As i understand it, nuclear fusion could (as soon as really achieved, i.e. there exist commercial plants) provide more energy than we are currently producing by all other methods. And if we can produce it, I have no doubt we would use more and more energy.
Which would mean that all this energy must end up somewhere somehow. What I would like to know is, don' we then (just in another form) contribute to the heating of the planet again? Are there any studies/theories about that? What would the impact of the ever increasing energy release/production be?
> 'Don't blame me,' said Poole, fighting back gamely after one round of criticism. 'Anyway, see what a mess the twenty-first century made.'
> There was a chorus of 'What do you mean?'s around the table.
> 'Well, as soon as the so-called Age of Infinite Power got under way, and everyone had thousands of kilowatts of cheap, clean energy to play with - you know what happened!'
> 'Oh, you mean the Thermal Crisis. But that was fixed.'
> 'Eventually - after you'd covered half the Earth with reflectors to bounce the Sun's heat back into space. Otherwise it would have been as parboiled as Venus by now.'
Yeah. This blog post [0] has a nice graph showing that at continued exponential growth of energy consumption, we have less than a few hundred years until the planet would become uninhabitable simply due to the amount of additional heat. In particular, in about 400 years, the energy demand would equal the total solar energy flux hitting the planet.
It’s a good question. I recall someone saying that the amount of direct heat produced by energy generation is very small compared to the heat captured from the sun by the greenhouse effect.
Also I don’t think it’s true that commercial fusion power plants would in the near term produce extraordinarily high energy levels compared to a large hydroelectric or fission nuclear power plant. The thing that’s great about fusion is that it requires very little fuel and doesn’t produce nuclear waste.
[+] [-] j15e|3 years ago|reply
> Lee Margetts at the University of Manchester, UK, says that the physics of fusion reactors is becoming well understood, but that there are technical hurdles to overcome before a working power plant can be built. Part of that will be developing methods to withdraw heat from the reactor and use it to generate electrical current.
> “It’s not physics, it’s engineering,” he says. “If you just think about this from the point of view of a gas-fired or a coal-fired power station, if you didn’t have anything to take the heat away, then the people operating it would say ‘we have to switch it off because it gets too hot and it will melt the power station’, and that’s exactly the situation here.”
[+] [-] gerdesj|3 years ago|reply
This was the first time I heard the "nuclear fusion is 25 years away" joke and it was told as such. We were also shown a graph of how many orders of magnitude away from ignition (for want of the correct word) by date. It had an initial steep decline but then turned right quite sharply and had annoying looking tendency to avoid the magic value.
Now, once you have ignition, you have to sustain it and extract power from it. That's quite tricky too!
[+] [-] cygx|3 years ago|reply
See p.4-5 of [1] for more recent plots. It includes earlier runs of both KSTAR (the experiment under discussion) and EAST (the Chinese one mentioned in another comment), but not their most recent ones.
[1] https://arxiv.org/abs/2105.10954
[+] [-] Hallucinaut|3 years ago|reply
[+] [-] rjzzleep|3 years ago|reply
[+] [-] elihu|3 years ago|reply
This made me wonder when ITER was going to actually be up and running. From wikipedia:
> "The reactor was expected to take 10 years to build and ITER had planned to test its first plasma in 2020 and achieve full fusion by 2023, however the schedule is now to test first plasma in 2025 and full fusion in 2035."
So, it sounds like it'll start doing something within a few years, but it'll probably be a long time before it produces significant scientific results.
By the time ITER is running, maybe some other group will beat them to it (like the MIT ARC or SPARC reactors, which use more recent, better superconductors and don't need to be anywhere near as big).
https://en.wikipedia.org/wiki/ITER
[+] [-] Kukumber|3 years ago|reply
https://news.cgtn.com/news/2021-12-31/China-s-artificial-sun...
[+] [-] motokamaks|3 years ago|reply
[+] [-] lake_vincent|3 years ago|reply
Half of the engineers on HN right now:
[...as long as the technique used can be scaled up...](PTSD_Chihuahua.jpg)
[+] [-] caseyavila|3 years ago|reply
In other words, are the byproducts able to form back into the "fuel" at a reasonable rate with the energy input of the Sun? I know that a selling point of fusion is that there is such an abundance of fuel that this doesn't matter. But if we treat finite energy sources as infinite, exponential growth in our energy budget means that we will undoubtedly run out of energy, as is being done with forests and such.
After all, I have a feeling people at the dawn of the industrial revolution thought the amount of coal available in the world would serve their needs "practically forever," until energy consumption scaled up by thousands of times.
[+] [-] marcyb5st|3 years ago|reply
Tritium, on the other hand, is a problem. It is radioactive with a half life of ~12 years and so the little we have needs to be produced since we can't really accumulate it. Currently it is produced by conventional nuclear reactors. Additionally, breeding tritium is harder than deuterium and requires a blanket around the reactor that uses other materials to multiply the number of stray neutrons. For each atom of Tritium that is fused we could get somewhere between 1.1 to 1.7 with a theoretical maximum of 2 Tritium atoms so, finally answering your question, it is renewable. It's just hard, but a piece of cake compared to actually maintaining a stable fusion.
[+] [-] BjoernKW|3 years ago|reply
However, for all practical intents and purposes, solar energy is renewable. The same holds true for nuclear fusion for at least a couple of hundred years, even considering growing energy consumption.
[+] [-] DennisP|3 years ago|reply
Deuterium fuel is the most abundant. There's enough in your morning shower to supply all your energy needs for a year. There's enough in the oceans to last for billions of years. Fusion is as close to renewable as anything, because it'll last until the sun goes out.
Right now most projects are also using tritium fuel, which has to be made from lithium. That's plenty abundant but not to the extreme of deuterium. But pure deuterium fusion is possible, just a little harder. And one prominent fusion startup, Helion, is actually using deuterium (along with helium-3, which is the waste product of deuterium fusion).
[+] [-] hoseja|3 years ago|reply
[+] [-] ncmncm|3 years ago|reply
There is no choice about that: it is the only way to get enough tritium to keep operating.
[+] [-] rr888|3 years ago|reply
[+] [-] ncmncm|3 years ago|reply
[deleted]
[+] [-] jacknews|3 years ago|reply
We should switch a good chunk of fussion funding towards 'clean' fission; travelling wave reactors, molten salt, small modular reactors, thorium, etc, etc. Some of these have a chance at being commercially viable and making a real impact this decade, not half a century or more hence.
[+] [-] bborud|3 years ago|reply
This is where much of the energy debate in Europe is at now. It is exactly the same argument being used against fission.
Pick any technology that has come to fruition in the last decade. Video streaming as a substitute for cable and terrestrial TV. Mass adoption of Smart Phones. EVs becoming a viable option for broad populations of car owners. A space startup that came from nowhere and rapidly out-competed the incumbents. All of them.
Remember the Apollo astronauts who walked on the moon shitting on private space companies on C-SPAN not that many years ago?
Look at the time span between people dismissing these technologies as off in the distant future and when they arrived. People have a tendency to assume that tomorrow will be the same as today.
Affordable nuclear is still some years away. I think the events in Europe actually shortened that distance into the future by a significant amount just in the last 6 months. But fission power is still "too slow". Fusion is even more years away into the future. If/When it comes to fruition people are going to be surprised, and none more so than the experts.
Because the experts are almost always wrong for a good while after disruptive breakthroughs have already happened.
It means we have to think ahead and make sufficient bets on technologies that exist at all time scales. And the more potential they have for delivering stable base load, the higher the payoff.
Yes we have to invest in both fission and fusion. And we have to invest a lot more than we already do.
[+] [-] DennisP|3 years ago|reply
Fix the NRC, and we might get somewhere with fission.
[+] [-] concordDance|3 years ago|reply
[+] [-] protoman3000|3 years ago|reply
I mean, doesn’t the atmosphere in our big greenhouse always retains a non-zero amount of energy, no matter the CO2 etc. in the air? If that is true, then so far the net energy out flux was positive, but now we see with rising greenhouse concentrations that it’s turning. If we then raise the stock of energy inside the greenhouse, it overheats, no?
[+] [-] scifibestfi|3 years ago|reply
[+] [-] alas44|3 years ago|reply
[+] [-] MichaelCollins|3 years ago|reply
[+] [-] quonn|3 years ago|reply
So it's still very challenging.
[+] [-] hinkley|3 years ago|reply
Greenhouse gases retain heat. Sea level temperature is a function of ambient heat due to sunlight and other heat sources, minus the rate at which it dissipates into outer space, mediated by the insulation effect of the atmosphere.
Projects that try to reduce the carbon intensity of energy are focused on changing the denominator in the equation. The current aim of these projects is to produce a cheap and plentiful energy source, via a heat engine. What they are actually chasing, whether they admit it to themselves or not, is a cheap and plentiful heat source. If they succeed they change both the numerator and the denominator, which ends up partially cancelling each other.
Wind and solar are different because they tap into an existing heat engine, instead of trying to build a new one.
What we as a people need is a fusion plant that costs less per KWH than a fossil fuel power plant with tariffs to account for the cost of the carbon dioxide, but still about as expensive as a fossil fuel plant where the carbon is free. If we actually got a fusion plant that was 10x more cost efficient then we'll just introduce the concept of heat pollution to the conversation, swapping out the villain in the story but keeping the same outcome.
[+] [-] mihaifm|3 years ago|reply
[+] [-] coffeeblack|3 years ago|reply
[+] [-] sien|3 years ago|reply
https://en.wikipedia.org/wiki/Project_Daedalus
[+] [-] thehappypm|3 years ago|reply
[+] [-] unknown|3 years ago|reply
[deleted]
[+] [-] Schroedingersat|3 years ago|reply
Not really. It'll just be another tool for the fossil fuel lobby to use to misdirect attention from what will make them irrelevant forever (reduction and sunlight).
Even if the reactor part is free and 100% reliable. Getting heat out of a 100 million degree chamber that is spewing neutrons everywhere and turning it into electricity is much much harder and more expensive than collecting some photons and building a train.
[+] [-] myrmidon|3 years ago|reply
We already have proven basically unlimited electric energy in the form of PV panels (and batteries if you need it stored). So far, that tech has not solved climate change at all, because actually building enough of these things is something that people need to be willing to pay for.
[+] [-] mmahemoff|3 years ago|reply
[+] [-] ncmncm|3 years ago|reply
[+] [-] kibwen|3 years ago|reply
[+] [-] z3rgl1ng|3 years ago|reply
[+] [-] sai_c|3 years ago|reply
As i understand it, nuclear fusion could (as soon as really achieved, i.e. there exist commercial plants) provide more energy than we are currently producing by all other methods. And if we can produce it, I have no doubt we would use more and more energy.
Which would mean that all this energy must end up somewhere somehow. What I would like to know is, don' we then (just in another form) contribute to the heating of the planet again? Are there any studies/theories about that? What would the impact of the ever increasing energy release/production be?
[+] [-] twic|3 years ago|reply
> There was a chorus of 'What do you mean?'s around the table.
> 'Well, as soon as the so-called Age of Infinite Power got under way, and everyone had thousands of kilowatts of cheap, clean energy to play with - you know what happened!'
> 'Oh, you mean the Thermal Crisis. But that was fixed.'
> 'Eventually - after you'd covered half the Earth with reflectors to bounce the Sun's heat back into space. Otherwise it would have been as parboiled as Venus by now.'
-- 3001: The final Odyssey, Arthur C. Clarke
Accuracy not guaranteed!
[+] [-] lambdatronics|3 years ago|reply
[0] https://dothemath.ucsd.edu/2011/07/galactic-scale-energy/
[+] [-] TaylorAlexander|3 years ago|reply
Also I don’t think it’s true that commercial fusion power plants would in the near term produce extraordinarily high energy levels compared to a large hydroelectric or fission nuclear power plant. The thing that’s great about fusion is that it requires very little fuel and doesn’t produce nuclear waste.
[+] [-] moomoo11|3 years ago|reply
How is the heat controlled? Is there any resource that explains this thermal part?
[+] [-] djyaz1200|3 years ago|reply
[+] [-] mikeInAlaska|3 years ago|reply
Was it hosted at the facility?
[+] [-] johndhi|3 years ago|reply
[+] [-] kushan2020|3 years ago|reply
I doubt a regular thermometer will scale at such levels.
[+] [-] gajus|3 years ago|reply
[+] [-] rkagerer|3 years ago|reply
https://en.m.wikipedia.org/wiki/Tokamak
[+] [-] taylorbuley|3 years ago|reply
Higher quality source: https://www.newscientist.com/article/2336385-korean-nuclear-...