7 ms·

New design could finally help to bring fusion power closer to reality

127 points by curtis 11y ago

deleted 11y ago
[deleted]
DennisP 11y ago
Meanwhile, MIT's fusion program is likely to be shut down soon. Their Alcator C-Mod has the strongest magnetic field of any tokamak in the world, and made a serious breakthrough in tokamak physics several years ago. I had a chance to visit a couple years ago. A grad student showed us a metal tie, about a meter long, and said they'd calculated that two of them could hold down the Space Shuttle during launch. To hold the reactor together when they switched it on, they needed 38 of them. They hadn't run the reactor for a year due to funding issues.
- mikeash 11y ago
  I had to run the numbers on that Space Shuttle thing, just to see. The Space Shuttle weighed about 4.5 million pounds at launch, and had a thrust-to-weight ratio of 1.5, meaning there was about 2.25 million pounds of net upward force on it. So each of those metal ties was capable of carrying a bit over a million pounds of load. Neat.
  - dosshell 11y ago
    And in Si units about: 500 000 kg (453 592.37)
    - gizmo686 11y ago
      kg is a unit of mass.The Si unit of force is the Newton.
      - richmarr 11y ago
        What's the SI unit of pedantry?
        blackbeard 11y ago
        Easier to understand than the American/Imperial one :)
Someone 11y ago
"The design could produce a reactor that would provide electricity to about 100,000 people, they say." It would be a huge step forward if this can be built, but there still would be a long way to go. To scale that to "electricity for everyone in the USA", you would need to build about 3,000 of these (or build much bigger ones). And that's for _current_ electricity use, not if everybody starts driving an electric car. For comparison, a 1000MW nuclear reactor produces electricity for 690,000 _households_ (http://www.nei.org/Knowledge-Center/Nuclear-Statistics/US-Nuclear-Power-Plants http://www.nei.org/Knowledge-Center/Nuclear-Statistics/US-Nu...), and US nuclear electricity generation is about a honderd times that (same page)
- mikeash 11y ago
  A fusion reactor able to produce net electricity at all would be a massive breakthrough. I don't think the size matters much at all. Once anything is working, progress on scaling it up is likely to come quickly. The hard part is getting to the point where it works at all. The first nuclear power plant attached to a grid was only 6MW. The first "full-scale" plant, according to Wikipedia and the BBC, had four reactors producing only 60MW each.
  - Someone 11y ago
    Honest question: how does this design scale up? Does scaling up mean making a bigger setup with magnets of the same strength? If so, I agree it is just a matter of making the effort, but this 150-ish MW thing is "half the size of ITER", which means it already is enormous (ITER will be gargantuan with its 1400 cubic meter vacuum vessel). Even at 'to the fourth power', I fear this would get really huge before it significantly improves on our largest fission reactors. Alternatively, can one inject more fusion material while keeping the same magnetic field strength to get more power out without building a larger device, or would that require stronger magnetic fields? If so, are we sure we can make those stronger fields? (Correction welcome, but I don't expect we can; if we could, we likely could scale this design down) I still think that, if this works as advertised, it will be both a huge result and only one important step on a long road ahead to 'free' clean energy.
- 11y ago
DrNuke 11y ago
The lab demonstration, if and when hopefully achieved, will be great but still a long way from full scale demonstration, licensing and commercialisation. Physics may eventually work well but engineering must hold up at 1:1 and make sense from several points of view. We're not there yet, ITER in Cadarache, France, being the nearest and biggest shot. Fingers crossed.
deleted 11y ago
[deleted]
- DennisP 11y ago
  Every other fusion article in the world already made that joke. Now that we're a decade away from working reactors, maybe we could consider retiring it.
iaw 11y ago
The big problem with controlled fusion, as I understand it, isn't creating a net energy positive fusion reactor like this article implies. The physics is already there, we just need the engineering to catch-up. The challenge is the materials that compose the reactor become brittle and highly radioactive far faster than usable. Controlled fusion as an energy source isn't just challenging because fusion is difficult, it's also challenging because materials don't handle neutron bombardment well. I think where this advancement is going to really help is in the iteration phase due to lower build costs but I'm still waiting for a solution to the radioactive economic issues associated with the materials these reactors would be constructed from.
- adeledeweylopez 11y ago
  It seems like they address this issue as well: "Another key advantage is that most of the solid blanket materials used to surround the fusion chamber in such reactors are replaced by a liquid material that can easily be circulated and replaced, eliminating the need for costly replacement procedures as the materials degrade over time. "It's an extremely harsh environment for [solid] materials," Whyte says, so replacing those materials with a liquid could be a major advantage."
  - iaw 11y ago
    It's been half a decade since I studied anything fusion related but IIRC regardless of using a liquid blanket you still have to have the machinery (powerful microwaves, particle injectors, etc) and the inner wall present. Liquid breeder blankets are definitely the way to go but I don't think they are the full solution. (They are super neat because you can use them to make more fuel for fusion through neutron capture, so not only do you reduce radioactivity but you also reuse the energy in a useful fashion)
- ZenoArrow 11y ago
  > "The challenge is the materials that compose the reactor become brittle and highly radioactive far faster than usable. Controlled fusion as an energy source isn't just challenging because fusion is difficult, it's also challenging because materials don't handle neutron bombardment well." Isn't that problem solved with aneutronic fusion? https://en.wikipedia.org/wiki/Aneutronic_fusion https://en.wikipedia.org/wiki/Aneutronic_fusion Of course we should focus on getting fusion working (working in the sense of providing more energy than we put in), regardless of whether we use the aneutronic approach or not, but as the field develops I'm optimistic we'll find ways to have robust fusion reactors.
throwaway_yy2Di 11y ago
Here's the paper (no paywall): http://arxiv.org/abs/1409.3540 http://arxiv.org/abs/1409.3540 Interesting that the liquid blanket is the same as in the molten-salt thorium reactors (lithium beryllium fluoride (FLiBe)).
- ethbro 11y ago
  Iananp, but wouldn't that be for the same reasons? E.g. in both case you're trying to absorb energetic neutrons? (Upon research: https://en.wikipedia.org/wiki/FLiBe#Coolant https://en.wikipedia.org/wiki/FLiBe#Coolant) Apparently it has properties that make it both a great coolant & a neutron moderator. Neat!
  - throwaway_yy2Di 11y ago
    They actually have nearly opposite goals. The fusion blanket is supposed to transmute lithium to tritium [0] (create more fusion fuel), so it has capture as many neutrons as possible. The fission-reactor coolant is supposed to be transparent -- to capture as few neutrons as possible. Both of them need isotopic separation of lithium to be practical. But in opposite directions. ARC's FLiBe needs to be Li-6 enriched, and MSR needs to be Li-6 depleted. The MSRE fuel used 99.993% Li-7 (your link), and the ARC blanket is 90% Li-6 (arXiv paper). [0] https://www.iter.org/mach/tritiumbreeding https://www.iter.org/mach/tritiumbreeding
moreati 11y ago
IANAP, but this sounds at least superficially similar to the reactor that Tokamak Energy are developing. Any nuclear physicists care to weigh in? """ Tokamak Energy is particularly focused on Spherical Tokamaks, pioneered at Culham, because these compact devices can achieve a much higher plasma pressure for a given magnetic field than conventional tokamaks, i.e. they are more efficient. Theoretical calculations show that a Spherical Tokamak using high fields produced by HTS magnets could be significantly smaller than other fusion machines currently proposed. For example, a compact ST power plant would have a volume up to 100 times smaller than ITER """ -- http://www.tokamakenergy.co.uk/about-us/ http://www.tokamakenergy.co.uk/about-us/
Gravityloss 11y ago
They use new high temperature superconducting wires to get those higher magnetic fields. If those superconductor wires become commonplace, they have some other uses as well...
glandium 11y ago
ARC: A compact, high-field, fusion nuclear science facility and demonstration power plant with demountable magnets Can it be miniaturized to power a suit?
alexggordon 11y ago
I think one of the biggest issues fusion power needs to deal with is whether or not it's worth the money. Renewable energy has gained serious momentum in the past years, and while it takes up significantly more land-mass-mass (things like solar panels and wind turbines), it requires less research and development than fusion, and is advancing at a significant pace. Contrast this with something like nuclear fusion, that has been under development for decades, and still has yet to produce a long term viable product. The one area I still think I see fusion reactors succeeding in, is that they can theoretically use nuclear waste as a fuel[0][1]. However, outside of Transatomic Power, I really don't see many fusion companies interested in dealing with that issue. Given fusions history of failure, I think that fusion energy really needs a hell of a selling point beyond a simple "we make energy" to be able to succeed. I think that selling point doesn't get much better than using nuclear waste as fuel. [0] http://www.transatomicpower.com/ http://www.transatomicpower.com/ [1] https://www.youtube.com/watch?v=4UXXwWOImm8 https://www.youtube.com/watch?v=4UXXwWOImm8
papasmrf 11y ago
Curious, IANAP, but suppose they get this to work? What would happen in the case of a magnetic field failure? I assume the magnetic field is generated by running electricity through the new material? What if the power fails?
guenthert 11y ago
Assuming this is the breakthrough the MIT press department makes it out to be, remaining engineering and material sciences questions can be solved and a commercially viable fusion reactor can indeed be constructed in the not too distant future, do we actually want one? Sure, this is fantastic news in a tech-geek, star-trek sense, but here in this reality, can we actually deploy such a thing? With the global climate in a delicate balance and energy released by fusing atomic cores or splitting them or even any process yielding energy not directly or indirectly gained recently from the sun is bound to increase the average temperature. A single reactor might not make a relevant or even measurable difference, but if a significant share of society's hunger for energy is to be satisfied this way, then it will, won't it (and if we're not sure, can we risk it)? So if this accelerates global warming, potentially even leading to a runaway greenhouse process (reducing earth albedo by shrinking the polar caps, releasing methane from the former perma-frost grounds in the Siberian tundra, etc.), then I hope they find us earth 2.0 and a way how to get there in a hurry.
- ectoplasm 11y ago
  The heat produced by humans is trivial compared to the heat produced by sunlight hitting the earth. That's why sources of energy that don't trap sunlight are desirable.

127 points by curtis 11y ago

deleted 11y ago

[deleted]

Meanwhile, MIT's fusion program is likely to be shut down soon. Their Alcator C-Mod has the strongest magnetic field of any tokamak in the world, and made a serious breakthrough in tokamak physics several years ago. I had a chance to visit a couple years ago. A grad student showed us a metal tie, about a meter long, and said they'd calculated that two of them could hold down the Space Shuttle during launch. To hold the reactor together when they switched it on, they needed 38 of them. They hadn't run the reactor for a year due to funding issues.

mikeash 11y ago
I had to run the numbers on that Space Shuttle thing, just to see. The Space Shuttle weighed about 4.5 million pounds at launch, and had a thrust-to-weight ratio of 1.5, meaning there was about 2.25 million pounds of net upward force on it. So each of those metal ties was capable of carrying a bit over a million pounds of load. Neat.
- dosshell 11y ago
  And in Si units about: 500 000 kg (453 592.37)
  - gizmo686 11y ago
    kg is a unit of mass.The Si unit of force is the Newton.
    - richmarr 11y ago
      What's the SI unit of pedantry?
      - blackbeard 11y ago
        Easier to understand than the American/Imperial one :)

Someone 11y ago

"The design could produce a reactor that would provide electricity to about 100,000 people, they say." It would be a huge step forward if this can be built, but there still would be a long way to go. To scale that to "electricity for everyone in the USA", you would need to build about 3,000 of these (or build much bigger ones). And that's for _current_ electricity use, not if everybody starts driving an electric car. For comparison, a 1000MW nuclear reactor produces electricity for 690,000 _households_ (http://www.nei.org/Knowledge-Center/Nuclear-Statistics/US-Nuclear-Power-Plants http://www.nei.org/Knowledge-Center/Nuclear-Statistics/US-Nu...), and US nuclear electricity generation is about a honderd times that (same page)

mikeash 11y ago
A fusion reactor able to produce net electricity at all would be a massive breakthrough. I don't think the size matters much at all. Once anything is working, progress on scaling it up is likely to come quickly. The hard part is getting to the point where it works at all. The first nuclear power plant attached to a grid was only 6MW. The first "full-scale" plant, according to Wikipedia and the BBC, had four reactors producing only 60MW each.
- Someone 11y ago
  Honest question: how does this design scale up? Does scaling up mean making a bigger setup with magnets of the same strength? If so, I agree it is just a matter of making the effort, but this 150-ish MW thing is "half the size of ITER", which means it already is enormous (ITER will be gargantuan with its 1400 cubic meter vacuum vessel). Even at 'to the fourth power', I fear this would get really huge before it significantly improves on our largest fission reactors. Alternatively, can one inject more fusion material while keeping the same magnetic field strength to get more power out without building a larger device, or would that require stronger magnetic fields? If so, are we sure we can make those stronger fields? (Correction welcome, but I don't expect we can; if we could, we likely could scale this design down) I still think that, if this works as advertised, it will be both a huge result and only one important step on a long road ahead to 'free' clean energy.
11y ago

DrNuke 11y ago

The lab demonstration, if and when hopefully achieved, will be great but still a long way from full scale demonstration, licensing and commercialisation. Physics may eventually work well but engineering must hold up at 1:1 and make sense from several points of view. We're not there yet, ITER in Cadarache, France, being the nearest and biggest shot. Fingers crossed.

deleted 11y ago

[deleted]

DennisP 11y ago
Every other fusion article in the world already made that joke. Now that we're a decade away from working reactors, maybe we could consider retiring it.

iaw 11y ago

The big problem with controlled fusion, as I understand it, isn't creating a net energy positive fusion reactor like this article implies. The physics is already there, we just need the engineering to catch-up. The challenge is the materials that compose the reactor become brittle and highly radioactive far faster than usable. Controlled fusion as an energy source isn't just challenging because fusion is difficult, it's also challenging because materials don't handle neutron bombardment well. I think where this advancement is going to really help is in the iteration phase due to lower build costs but I'm still waiting for a solution to the radioactive economic issues associated with the materials these reactors would be constructed from.

adeledeweylopez 11y ago
It seems like they address this issue as well: "Another key advantage is that most of the solid blanket materials used to surround the fusion chamber in such reactors are replaced by a liquid material that can easily be circulated and replaced, eliminating the need for costly replacement procedures as the materials degrade over time. "It's an extremely harsh environment for [solid] materials," Whyte says, so replacing those materials with a liquid could be a major advantage."
- iaw 11y ago
  It's been half a decade since I studied anything fusion related but IIRC regardless of using a liquid blanket you still have to have the machinery (powerful microwaves, particle injectors, etc) and the inner wall present. Liquid breeder blankets are definitely the way to go but I don't think they are the full solution. (They are super neat because you can use them to make more fuel for fusion through neutron capture, so not only do you reduce radioactivity but you also reuse the energy in a useful fashion)
ZenoArrow 11y ago
> "The challenge is the materials that compose the reactor become brittle and highly radioactive far faster than usable. Controlled fusion as an energy source isn't just challenging because fusion is difficult, it's also challenging because materials don't handle neutron bombardment well." Isn't that problem solved with aneutronic fusion? https://en.wikipedia.org/wiki/Aneutronic_fusion https://en.wikipedia.org/wiki/Aneutronic_fusion Of course we should focus on getting fusion working (working in the sense of providing more energy than we put in), regardless of whether we use the aneutronic approach or not, but as the field develops I'm optimistic we'll find ways to have robust fusion reactors.

throwaway_yy2Di 11y ago

Here's the paper (no paywall): http://arxiv.org/abs/1409.3540 http://arxiv.org/abs/1409.3540 Interesting that the liquid blanket is the same as in the molten-salt thorium reactors (lithium beryllium fluoride (FLiBe)).

ethbro 11y ago
Iananp, but wouldn't that be for the same reasons? E.g. in both case you're trying to absorb energetic neutrons? (Upon research: https://en.wikipedia.org/wiki/FLiBe#Coolant https://en.wikipedia.org/wiki/FLiBe#Coolant) Apparently it has properties that make it both a great coolant & a neutron moderator. Neat!
- throwaway_yy2Di 11y ago
  They actually have nearly opposite goals. The fusion blanket is supposed to transmute lithium to tritium [0] (create more fusion fuel), so it has capture as many neutrons as possible. The fission-reactor coolant is supposed to be transparent -- to capture as few neutrons as possible. Both of them need isotopic separation of lithium to be practical. But in opposite directions. ARC's FLiBe needs to be Li-6 enriched, and MSR needs to be Li-6 depleted. The MSRE fuel used 99.993% Li-7 (your link), and the ARC blanket is 90% Li-6 (arXiv paper). [0] https://www.iter.org/mach/tritiumbreeding https://www.iter.org/mach/tritiumbreeding

moreati 11y ago

IANAP, but this sounds at least superficially similar to the reactor that Tokamak Energy are developing. Any nuclear physicists care to weigh in? """ Tokamak Energy is particularly focused on Spherical Tokamaks, pioneered at Culham, because these compact devices can achieve a much higher plasma pressure for a given magnetic field than conventional tokamaks, i.e. they are more efficient. Theoretical calculations show that a Spherical Tokamak using high fields produced by HTS magnets could be significantly smaller than other fusion machines currently proposed. For example, a compact ST power plant would have a volume up to 100 times smaller than ITER """ -- http://www.tokamakenergy.co.uk/about-us/ http://www.tokamakenergy.co.uk/about-us/

Gravityloss 11y ago

They use new high temperature superconducting wires to get those higher magnetic fields. If those superconductor wires become commonplace, they have some other uses as well...

glandium 11y ago

ARC: A compact, high-field, fusion nuclear science facility and demonstration power plant with demountable magnets Can it be miniaturized to power a suit?

alexggordon 11y ago

I think one of the biggest issues fusion power needs to deal with is whether or not it's worth the money. Renewable energy has gained serious momentum in the past years, and while it takes up significantly more land-mass-mass (things like solar panels and wind turbines), it requires less research and development than fusion, and is advancing at a significant pace. Contrast this with something like nuclear fusion, that has been under development for decades, and still has yet to produce a long term viable product. The one area I still think I see fusion reactors succeeding in, is that they can theoretically use nuclear waste as a fuel[0][1]. However, outside of Transatomic Power, I really don't see many fusion companies interested in dealing with that issue. Given fusions history of failure, I think that fusion energy really needs a hell of a selling point beyond a simple "we make energy" to be able to succeed. I think that selling point doesn't get much better than using nuclear waste as fuel. [0] http://www.transatomicpower.com/ http://www.transatomicpower.com/ [1] https://www.youtube.com/watch?v=4UXXwWOImm8 https://www.youtube.com/watch?v=4UXXwWOImm8

papasmrf 11y ago

Curious, IANAP, but suppose they get this to work? What would happen in the case of a magnetic field failure? I assume the magnetic field is generated by running electricity through the new material? What if the power fails?

guenthert 11y ago

Assuming this is the breakthrough the MIT press department makes it out to be, remaining engineering and material sciences questions can be solved and a commercially viable fusion reactor can indeed be constructed in the not too distant future, do we actually want one? Sure, this is fantastic news in a tech-geek, star-trek sense, but here in this reality, can we actually deploy such a thing? With the global climate in a delicate balance and energy released by fusing atomic cores or splitting them or even any process yielding energy not directly or indirectly gained recently from the sun is bound to increase the average temperature. A single reactor might not make a relevant or even measurable difference, but if a significant share of society's hunger for energy is to be satisfied this way, then it will, won't it (and if we're not sure, can we risk it)? So if this accelerates global warming, potentially even leading to a runaway greenhouse process (reducing earth albedo by shrinking the polar caps, releasing methane from the former perma-frost grounds in the Siberian tundra, etc.), then I hope they find us earth 2.0 and a way how to get there in a hurry.

ectoplasm 11y ago
The heat produced by humans is trivial compared to the heat produced by sunlight hitting the earth. That's why sources of energy that don't trap sunlight are desirable.