11 ms·

A Commercial Path to Fusion

142 points by theothermkn 7y ago

Balero 7y ago
For anyone interested in learning more about the history of fusion power research I would recommend the book: A Piece of the Sun: The Quest for Fusion Energy I found it informative, and a really easy read to get a good overview of the history of the research.
- dmix 7y ago
  Agreed this a great history about how the standard designs came about, particularly the two big ones historically: Tokamak (Soviet approach, mentioned in this article) and Stellarator (US/Princeton approach). Then later in the 1970s ICE using lasers (inertial confinement fusion) which is the other dominant form in modern attempts since Stellarator hasn't worked out. Reads a bit like those Manhattan Project books. https://www.amazon.com/Piece-Sun-Quest-Fusion-Energy/dp/B00DRG3WH2/ https://www.amazon.com/Piece-Sun-Quest-Fusion-Energy/dp/B00D...
  - chiefalchemist 7y ago
    Approx four or five years ago I had an accidental/random conversation with one of the prominent researchers at the Princeton facility (PPPL). Long to short, he said, "We're getting there. The more funding we have, the sooner we'll get there. But yeah, we're really close." Mind you, that's what any research scientist would say. But everything I've seen and read since tells me he's was being honest and has been accurate. I hope he's right. https://www.pppl.gov/ https://www.pppl.gov/
    - makerofspoons 7y ago
      I have a good friend who is a physics graduate student at Princeton working on fusion and he has said the same.
      - pault 7y ago
        I was very close to finishing a 2 week project 6 weeks ago.
    - Iv 7y ago
      That's really one of my dream: that fusion ends up being up in the corner and suddenly the energy crisis is over.
      - chiefalchemist 7y ago
        I too will be happy to see the clean energy problem solved. On the other hand, if big oil - and the countries that depend on it - implodes then we have a new problem. That's not pretty.
    - fnord77 7y ago
      ITER is 5 years from first plasma and 15 years from full operation. With all the various experiments over the years, if we haven't gotten ignition by now, we'll never get it. Fusion is going to be perpetually "just 5-10 years away" https://www.scientificamerican.com/article/worlds-largest-nuclear-fusion-experiment-clears-milestone/ https://www.scientificamerican.com/article/worlds-largest-nu...
    - pfdietz 7y ago
      He was lying to you, or misleading you. We may be really close to Q>1. That would put fusion where fission was in 1942. It would not mean we were, or ever could be, close to practical fusion power plants.
  - Animats 7y ago
    Inertial confinement fusion was for fusion bomb technology development. It's used to produce bomb-like conditions on a laboratory scale. It was once billed as having something to do with energy production, but that was for PR purposes only.
    - snissn 7y ago
      [citation needed]
      - Animats 7y ago
        It's not hard to find.[1] [1] https://thebulletin.org/2013/07/nuclear-weapons-the-death-of-fusion/ https://thebulletin.org/2013/07/nuclear-weapons-the-death-of...
        snissn 7y ago
        Ok let's agree to disagree with the idea that ICF never had a legitimate energy purpose. Goodbye
        pfdietz 7y ago
        What ICF did was play off the weapons and the energy people. When one side raised questions about the validity of the justification for ICF from their side's point of view, the ICF people could just point to the other side. I think in the end the real justification was maintaining a cadre of physicists who were familiar and experienced with the physics of materials at H-bomb like conditions, in case new generations of bombs needed to be designed, and also to help validate improved computer codes for simulating those conditions without actual bomb tests.
  - Ygg2 7y ago
    Stellator didn't work out? What is Wendelstein 7-X then? Christmas lights?
    - dmix 7y ago
      Apologies I didn't phrase that right. There's been more recent work on Stellator. The book takes a longer history look at it and didn't dwell very long on modern developments. Stellator definitely took a decline in popularity at one point before making a bit of a comeback with Wendelstein 7-X and some other places.
    - pfdietz 7y ago
      Stellarators will have the same low power density of tokamaks. They are not immune to the generic arguments Lidsky, Pfirsch, and Schmitter made against DT fusion reactors.
  - pinewurst 7y ago
    An oldie but a goodie is "Man Made Sun: The Quest for Fusion Power" by T.A. Heppenheimer from 1984 or so.
- snissn 7y ago
  thanks for the recommendation! In college I took a senior/grad level class on controlled fusion and this was the text book that was used: https://www.amazon.com/Principles-Fusion-Energy-Introduction-Engineering/dp/9812380337 https://www.amazon.com/Principles-Fusion-Energy-Introduction... (https://classes.cornell.edu/browse/roster/SP18/class/ECE/4840 https://classes.cornell.edu/browse/roster/SP18/class/ECE/484...)
- sien 7y ago
  That's a really good book. Another one that is also very good is "The Future of Fusion Energy" which has lots on modern methods. https://www.amazon.com/Future-Fusion-Energy-Jason-Parisi/dp/1786345420 https://www.amazon.com/Future-Fusion-Energy-Jason-Parisi/dp/... Also well worth checking are the podcasts 'Physical Attraction' which has done many episodes on fusion and 'Omega Tau' that has long episodes on ITER, Wendelstein 7X and superconductors.
evdev 7y ago
For a breakdown of the reasoning behind the project, if you haven't already seen it: https://www.youtube.com/watch?v=L0KuAx1COEk https://www.youtube.com/watch?v=L0KuAx1COEk
- rhcom2 7y ago
  For a layman this was incredibly interesting. The speaker explains the concepts very well.
- TecoAndJix 7y ago
  That video was super informative! Thank you for sharing it
kybernetikos 7y ago
The plasma needs to be >=200 million kelvin, the superconductor that contains it doesn't work if its not <=20 kelvin. No wonder this is an engineering nightmare! I wonder if gradients that extreme exist in nature.
- deleted 7y ago
  [deleted]
- gct 7y ago
  The magnets are on the outside of the containment vessel, their whole point is to keep the plasma in the center. What little leaks out ablates the walls of the container, it never even touches the magnets.
- DennisP 7y ago
  I won't say it's not challenging, but bear in mind that while the plasma is at high temperature, it has very low density. The atoms are moving really fast but there aren't many of them. Consequently the amount of heat is comparable to fossil plants.
Animats 7y ago
The SPARC project’s first task, over the next few years, will be to build and test a full-scale prototype HTS fusion magnet. ... one of the primary missions of the prototype HTS coil will be to investigate our ability to detect and mitigate a “quench” event, which is a sudden loss of superconductivity. Good for a decade of funding and theses before having to actually work on fusion. This is not a "commercial path to fusion". This is superconducting magnet R&D.
numakerg 7y ago
How would a commercial venture plan to recoup their investment cost when (if) they finally reach a viable reactor design? If an American/European company came out with a working reactor, would India and China pay for the technology, or would they put hundreds of billions into developing their own? What about the opposite scenario? Even a tiny peek at the design would shave off a large portion of the cutting edge investment. On the other hand, fusion could completely alter the course of climate change, perhaps it's cheaper in the long run to just give out the technology.
- Zigurd 7y ago
  Disney manages to get them to pay for movies enough of the time. Reactors are more difficult to bootleg.
hairytrog 7y ago
This is R&D - not a commercial path. These types of fusion projects are trying to prove the most basic piece of the puzzle: net energy generation. And it is a big problem, even for Commonwealth. I've heard that the magnets are underperforming by about a factor of 2 - and that's 4 years into the project. But commercialization is a lot more than just proving that the concept is physically possible. It was proven possible that man could walk on the moon, but it's not a commercial activity 50 years in. Commercialization for nuclear energy systems means global deployment, mass manufacturing, lack of proliferation risk, extreme safety, etc. Fusion systems like Commonwealth's do not meet any of these criteria. They are constantly generating radioactive waste because they have to breed their fuel and reprocess it on site. To commercialize, you have to be able to deploy the technology in a significantly better way than traditional fission. These large fusion prototypes ($65B for ITER and $5B for Commonwealth based on their 2015 white paper, so probably 2-4x larger now) exacerbate traditional nuclear's cost problems because they are construction projects that will last decades. Viable nuclear solutions will be factory manufactured rather than constructed. For comments from MIT dissenter in 80s that stand true today: http://orcutt.net/weblog/wp-content/uploads/2015/08/The-Trouble-With-Fusion_MIT_Tech_Review_1983.pdf http://orcutt.net/weblog/wp-content/uploads/2015/08/The-Trou... For a review of fusion problems: https://thebulletin.org/2018/02/iter-is-a-showcase-for-the-drawbacks-of-fusion-energy/ https://thebulletin.org/2018/02/iter-is-a-showcase-for-the-d...
- deleted 7y ago
  [deleted]
- trhway 7y ago
  yep, at least until we get aneutronic fusion going with direct schema of electricity generation bypassing the heat engines, the fusion on Earth has no chances of competing with the most of the existing and especially solar/wind energy sources. Other than that the 2 most interesting potential applications are weapons and space propulsion. Those applications are better served by inertial confinement (laser, Z-machine, fusor, DPF) which historically been showing better results and usually at much lower costs (and even the high cost NIF can be redone today using modern solid state which would lower the cost/size dramatically) yet historically the resources have been poured into the huge systems like Tokamak.
AtlasBarfed 7y ago
Don't fusion reactors have problems with vessel degradation from fast neutrons turning the reactors themselves into radioactive waste? LFTR is what fusion should have been, and should have gotten equivalent funding. Plentiful fuel (thorium), can "burn" current nuclear waste as fuel, meltdown safe, etc etc etc. And they can scale down to pretty small sizes, per another commenter's "construction" vs "factory production" comment. The only interesting fusion idea I've seen is antimatter catalyze fusion rockets for space travel. Wind/Solar/Storage have won. This would be wasted money.
- travisoneill1 7y ago
  If they have won why do they not power most of the grid?
  - ben_w 7y ago
    Inertia. If I remember right, if you look at how the distribution of new power sources rather than existing ones, more than half of new power is renewable.
  - munk-a 7y ago
    Within America, at least, there are still quite heavy subsidies to fossil fuels companies to keep them competitive and keep jobs local - their survival is partially due to some heavy market manipulation by the government.
  - pfdietz 7y ago
    Because renewables have improved on a timescale short compared to the design lifetime of typical generating equipment. This is an unusual situation in the power business, and it means much of the installed base is zombie tech, obsolete stuff that wouldn't be used if the cost weren't sunk.
- ben_w 7y ago
  > Don't fusion reactors have problems with vessel degradation from fast neutrons turning the reactors themselves into radioactive waste? Yea and no. More neutrons per joule of output, but the waste is short-lived and easier to manage. But also the neutron flux is so large that every atom will get knocked out of its lattice over the reactor lifetime, so the metallurgy is (I’m told by a metallurgist) complicated.
digikata 7y ago
The Omega Tau podcast had some very interesting discussions about various improvements needed for fusions reactors to hit parity in their Wendelstein 7x episode. Some discussions I think come out all the more because the 7x was targeted to plasma research so many practical aspects are discussed outside the normal fusion discussion that hits regular science media. https://omegataupodcast.net/312-the-wendelstein-7-x-fusion-experiment/ https://omegataupodcast.net/312-the-wendelstein-7-x-fusion-e...
carapace 7y ago
FWIW, Dr. Robert Bussard claimed in 2006 that the inertial electrostatic confinement fusor could be developed for ~$200M IIRC https://en.wikipedia.org/wiki/Inertial_electrostatic_confinement https://en.wikipedia.org/wiki/Inertial_electrostatic_confine... "Should Google Go Nuclear? Clean, cheap, nuclear power (no, really)" https://www.youtube.com/watch?v=rk6z1vP4Eo8 https://www.youtube.com/watch?v=rk6z1vP4Eo8
- pfdietz 7y ago
  I wouldn't believe that for a moment, and Google probably didn't either. It's interesting how the internet enables wishful thinking like this. You'd have thought the dearth of peer reviewed papers about Polywell would have been a clue, but true believers admit no impediment to their belief. There are good theoretical reasons to believe IEC fusion cannot work on advanced fuels, reasons that HAVE appeared in the peer reviewed literature.
  - carapace 7y ago
    Absence of evidence is not evidence of absence. Would it be so terrible to do a little more research? If only to honor Dr Bussard's (RIP) memory? Google's not hurting for cash right now? "When a physicist tells you something is possible you should believe him, when a physicist tells you something is impossible you should doubt him." I forget who said that, but it holds. Lots of things had "good theoretical reasons" for not working until someone figured out how. Planes? Visiting the Moon?
    - pfdietz 7y ago
      Absence of evidence is evidence of shenanigans. If someone is making a claim, especially a remarkable claim, it is their responsibility to provide evidence for their claim. If they cannot, or if their evidence is such that it cannot pass peer review, something stinks, and one should be highly skeptical. This is not a case of "no one has shown X, therefore X should be dismissed". It's "P has claimed X, but has not shown evidence to justify their claim, therefore their claim should not be believed." If someone holds a position, presumably they had a good reason to do that, and one can ask for that reasoning and evidence (and ask that that reasoning and evidence be verified by peer review.)
peteretep 7y ago
With renewables getting better every day, at what point will they make fusion reactors irrelevant?
- theothermkn 7y ago
  Saul Griffith has an old talk entitled "Climate Change Recalculated." The gist is that he converts everyday energy consumption into averaged watts over a day, and then looks at the energy area density of renewables. The resulting picture is rather daunting. If we go 100% renewable--If we even could!--all of our lifestyles would be radically curtailed, and this is after a construction binge of enormous scale. We absolutely need fission and/or fusion. Of this there is no doubt.
  - pfdietz 7y ago
    Yeah, that's bullshit. Energy density of renewables doesn't preclude current lifestyles. The Earth is constantly hit by 100,000 TW of sunlight, and the energy collected doesn't have to be used near where the collectors are.
    - serioussecurity 7y ago
      Density in this case referring to "kW per acre of solar panels", and the #s come out to something like covering all of Australia with solar panels, if I remember correctly.
      - peteretep 7y ago
        > and the #s come out to something like covering all of Australia with solar panels, if I remember correctly You do not remember correctly. Estimates seem to vary, but Musk reckons 100 miles by 100 miles for America[0] which I make as 0.003% of Australia. It's a large (if imaginary) place. [0] https://futurism.com/elon-musk-tells-national-governors-association-how-we-could-power-the-u-s-with-solar https://futurism.com/elon-musk-tells-national-governors-asso...
xchaotic 7y ago
What I find particularly troubling about the design of tokamak reactors is that on one hand you have magnets that need to be cooled to -250C or whatever the “high” temperature is nowadays and in the middle of it you have plasma that will leak thermal radiation in any way possible. The magnets themselves will heat up from running large electric currents through them. This just feels like a recipe for a disaster - if things suddenly stop working, due to heat or otherwise you have a very hot, radioactive plasma trying to equalise its energy with the outer world...
- theothermkn 7y ago
  Well, there's kind of a chain of intuitions here that are off by up to orders of magnitude. First, YBCO has a critical temperature of 93K, not 23K or so as you've suggested (albeit not as a value for YBCO). In other words, there have been advances in high temperature superconductors. Second, the magnets will not heat up from having large currents running through them. This is the point of superconductors. So, this estimate of resistivity is high by several orders of magnitude. Third, any estimate of the total energy of the hot plasma that gets us anywhere near verbiage hinting at explosions is too high by several orders of magnitude. You could typically extinguish a burning plasma by blowing gently on it. Finally, the thermal gradients aren't nearly so dire as, you know, 200e6K immediately next to 90K. There is typically over a meter of, in order: near-vacuum; inner wall; flowing lithium blanket; outer wall; and liquid nitrogen or other cryogenic coolant, all between the plasma and the magnets. This is the farthest thing from a recipe for disaster.
  - grogers 7y ago
    Just want to point out that specific critical temperature varies with magnetic field. The article mentions 12T and 20K so presumably that is within some reasonable safety margin of the limit for YBCO at that field strength.
Swivekth18 7y ago
SPARC is an HTS experiment, showing the viability of compact Q>1 using the technology, showing you don't have to be ITER -size to have successful fusion. It doesn't claim to be and won't be much more than that. An important step, nonetheless.

142 points by theothermkn 7y ago

For anyone interested in learning more about the history of fusion power research I would recommend the book: A Piece of the Sun: The Quest for Fusion Energy I found it informative, and a really easy read to get a good overview of the history of the research.

dmix 7y ago
Agreed this a great history about how the standard designs came about, particularly the two big ones historically: Tokamak (Soviet approach, mentioned in this article) and Stellarator (US/Princeton approach). Then later in the 1970s ICE using lasers (inertial confinement fusion) which is the other dominant form in modern attempts since Stellarator hasn't worked out. Reads a bit like those Manhattan Project books. https://www.amazon.com/Piece-Sun-Quest-Fusion-Energy/dp/B00DRG3WH2/ https://www.amazon.com/Piece-Sun-Quest-Fusion-Energy/dp/B00D...
- chiefalchemist 7y ago
  Approx four or five years ago I had an accidental/random conversation with one of the prominent researchers at the Princeton facility (PPPL). Long to short, he said, "We're getting there. The more funding we have, the sooner we'll get there. But yeah, we're really close." Mind you, that's what any research scientist would say. But everything I've seen and read since tells me he's was being honest and has been accurate. I hope he's right. https://www.pppl.gov/ https://www.pppl.gov/
  - makerofspoons 7y ago
    I have a good friend who is a physics graduate student at Princeton working on fusion and he has said the same.
    - pault 7y ago
      I was very close to finishing a 2 week project 6 weeks ago.
  - Iv 7y ago
    That's really one of my dream: that fusion ends up being up in the corner and suddenly the energy crisis is over.
    - chiefalchemist 7y ago
      I too will be happy to see the clean energy problem solved. On the other hand, if big oil - and the countries that depend on it - implodes then we have a new problem. That's not pretty.
  - fnord77 7y ago
    ITER is 5 years from first plasma and 15 years from full operation. With all the various experiments over the years, if we haven't gotten ignition by now, we'll never get it. Fusion is going to be perpetually "just 5-10 years away" https://www.scientificamerican.com/article/worlds-largest-nuclear-fusion-experiment-clears-milestone/ https://www.scientificamerican.com/article/worlds-largest-nu...
  - pfdietz 7y ago
    He was lying to you, or misleading you. We may be really close to Q>1. That would put fusion where fission was in 1942. It would not mean we were, or ever could be, close to practical fusion power plants.
- Animats 7y ago
  Inertial confinement fusion was for fusion bomb technology development. It's used to produce bomb-like conditions on a laboratory scale. It was once billed as having something to do with energy production, but that was for PR purposes only.
  - snissn 7y ago
    [citation needed]
    - Animats 7y ago
      It's not hard to find.[1] [1] https://thebulletin.org/2013/07/nuclear-weapons-the-death-of-fusion/ https://thebulletin.org/2013/07/nuclear-weapons-the-death-of...
      - snissn 7y ago
        Ok let's agree to disagree with the idea that ICF never had a legitimate energy purpose. Goodbye
        pfdietz 7y ago
        What ICF did was play off the weapons and the energy people. When one side raised questions about the validity of the justification for ICF from their side's point of view, the ICF people could just point to the other side. I think in the end the real justification was maintaining a cadre of physicists who were familiar and experienced with the physics of materials at H-bomb like conditions, in case new generations of bombs needed to be designed, and also to help validate improved computer codes for simulating those conditions without actual bomb tests.
- Ygg2 7y ago
  Stellator didn't work out? What is Wendelstein 7-X then? Christmas lights?
  - dmix 7y ago
    Apologies I didn't phrase that right. There's been more recent work on Stellator. The book takes a longer history look at it and didn't dwell very long on modern developments. Stellator definitely took a decline in popularity at one point before making a bit of a comeback with Wendelstein 7-X and some other places.
  - pfdietz 7y ago
    Stellarators will have the same low power density of tokamaks. They are not immune to the generic arguments Lidsky, Pfirsch, and Schmitter made against DT fusion reactors.
- pinewurst 7y ago
  An oldie but a goodie is "Man Made Sun: The Quest for Fusion Power" by T.A. Heppenheimer from 1984 or so.
snissn 7y ago
thanks for the recommendation! In college I took a senior/grad level class on controlled fusion and this was the text book that was used: https://www.amazon.com/Principles-Fusion-Energy-Introduction-Engineering/dp/9812380337 https://www.amazon.com/Principles-Fusion-Energy-Introduction... (https://classes.cornell.edu/browse/roster/SP18/class/ECE/4840 https://classes.cornell.edu/browse/roster/SP18/class/ECE/484...)
sien 7y ago
That's a really good book. Another one that is also very good is "The Future of Fusion Energy" which has lots on modern methods. https://www.amazon.com/Future-Fusion-Energy-Jason-Parisi/dp/1786345420 https://www.amazon.com/Future-Fusion-Energy-Jason-Parisi/dp/... Also well worth checking are the podcasts 'Physical Attraction' which has done many episodes on fusion and 'Omega Tau' that has long episodes on ITER, Wendelstein 7X and superconductors.

evdev 7y ago

For a breakdown of the reasoning behind the project, if you haven't already seen it: https://www.youtube.com/watch?v=L0KuAx1COEk https://www.youtube.com/watch?v=L0KuAx1COEk

rhcom2 7y ago
For a layman this was incredibly interesting. The speaker explains the concepts very well.
TecoAndJix 7y ago
That video was super informative! Thank you for sharing it

kybernetikos 7y ago

The plasma needs to be >=200 million kelvin, the superconductor that contains it doesn't work if its not <=20 kelvin. No wonder this is an engineering nightmare! I wonder if gradients that extreme exist in nature.

deleted 7y ago
[deleted]
gct 7y ago
The magnets are on the outside of the containment vessel, their whole point is to keep the plasma in the center. What little leaks out ablates the walls of the container, it never even touches the magnets.
DennisP 7y ago
I won't say it's not challenging, but bear in mind that while the plasma is at high temperature, it has very low density. The atoms are moving really fast but there aren't many of them. Consequently the amount of heat is comparable to fossil plants.

Animats 7y ago

The SPARC project’s first task, over the next few years, will be to build and test a full-scale prototype HTS fusion magnet. ... one of the primary missions of the prototype HTS coil will be to investigate our ability to detect and mitigate a “quench” event, which is a sudden loss of superconductivity. Good for a decade of funding and theses before having to actually work on fusion. This is not a "commercial path to fusion". This is superconducting magnet R&D.

numakerg 7y ago

How would a commercial venture plan to recoup their investment cost when (if) they finally reach a viable reactor design? If an American/European company came out with a working reactor, would India and China pay for the technology, or would they put hundreds of billions into developing their own? What about the opposite scenario? Even a tiny peek at the design would shave off a large portion of the cutting edge investment. On the other hand, fusion could completely alter the course of climate change, perhaps it's cheaper in the long run to just give out the technology.

Zigurd 7y ago
Disney manages to get them to pay for movies enough of the time. Reactors are more difficult to bootleg.

hairytrog 7y ago

This is R&D - not a commercial path. These types of fusion projects are trying to prove the most basic piece of the puzzle: net energy generation. And it is a big problem, even for Commonwealth. I've heard that the magnets are underperforming by about a factor of 2 - and that's 4 years into the project. But commercialization is a lot more than just proving that the concept is physically possible. It was proven possible that man could walk on the moon, but it's not a commercial activity 50 years in. Commercialization for nuclear energy systems means global deployment, mass manufacturing, lack of proliferation risk, extreme safety, etc. Fusion systems like Commonwealth's do not meet any of these criteria. They are constantly generating radioactive waste because they have to breed their fuel and reprocess it on site. To commercialize, you have to be able to deploy the technology in a significantly better way than traditional fission. These large fusion prototypes ($65B for ITER and $5B for Commonwealth based on their 2015 white paper, so probably 2-4x larger now) exacerbate traditional nuclear's cost problems because they are construction projects that will last decades. Viable nuclear solutions will be factory manufactured rather than constructed. For comments from MIT dissenter in 80s that stand true today: http://orcutt.net/weblog/wp-content/uploads/2015/08/The-Trouble-With-Fusion_MIT_Tech_Review_1983.pdf http://orcutt.net/weblog/wp-content/uploads/2015/08/The-Trou... For a review of fusion problems: https://thebulletin.org/2018/02/iter-is-a-showcase-for-the-drawbacks-of-fusion-energy/ https://thebulletin.org/2018/02/iter-is-a-showcase-for-the-d...

deleted 7y ago
[deleted]
trhway 7y ago
yep, at least until we get aneutronic fusion going with direct schema of electricity generation bypassing the heat engines, the fusion on Earth has no chances of competing with the most of the existing and especially solar/wind energy sources. Other than that the 2 most interesting potential applications are weapons and space propulsion. Those applications are better served by inertial confinement (laser, Z-machine, fusor, DPF) which historically been showing better results and usually at much lower costs (and even the high cost NIF can be redone today using modern solid state which would lower the cost/size dramatically) yet historically the resources have been poured into the huge systems like Tokamak.

AtlasBarfed 7y ago

Don't fusion reactors have problems with vessel degradation from fast neutrons turning the reactors themselves into radioactive waste? LFTR is what fusion should have been, and should have gotten equivalent funding. Plentiful fuel (thorium), can "burn" current nuclear waste as fuel, meltdown safe, etc etc etc. And they can scale down to pretty small sizes, per another commenter's "construction" vs "factory production" comment. The only interesting fusion idea I've seen is antimatter catalyze fusion rockets for space travel. Wind/Solar/Storage have won. This would be wasted money.

travisoneill1 7y ago
If they have won why do they not power most of the grid?
- ben_w 7y ago
  Inertia. If I remember right, if you look at how the distribution of new power sources rather than existing ones, more than half of new power is renewable.
- munk-a 7y ago
  Within America, at least, there are still quite heavy subsidies to fossil fuels companies to keep them competitive and keep jobs local - their survival is partially due to some heavy market manipulation by the government.
- pfdietz 7y ago
  Because renewables have improved on a timescale short compared to the design lifetime of typical generating equipment. This is an unusual situation in the power business, and it means much of the installed base is zombie tech, obsolete stuff that wouldn't be used if the cost weren't sunk.
ben_w 7y ago
> Don't fusion reactors have problems with vessel degradation from fast neutrons turning the reactors themselves into radioactive waste? Yea and no. More neutrons per joule of output, but the waste is short-lived and easier to manage. But also the neutron flux is so large that every atom will get knocked out of its lattice over the reactor lifetime, so the metallurgy is (I’m told by a metallurgist) complicated.

digikata 7y ago

The Omega Tau podcast had some very interesting discussions about various improvements needed for fusions reactors to hit parity in their Wendelstein 7x episode. Some discussions I think come out all the more because the 7x was targeted to plasma research so many practical aspects are discussed outside the normal fusion discussion that hits regular science media. https://omegataupodcast.net/312-the-wendelstein-7-x-fusion-experiment/ https://omegataupodcast.net/312-the-wendelstein-7-x-fusion-e...

carapace 7y ago

FWIW, Dr. Robert Bussard claimed in 2006 that the inertial electrostatic confinement fusor could be developed for ~$200M IIRC https://en.wikipedia.org/wiki/Inertial_electrostatic_confinement https://en.wikipedia.org/wiki/Inertial_electrostatic_confine... "Should Google Go Nuclear? Clean, cheap, nuclear power (no, really)" https://www.youtube.com/watch?v=rk6z1vP4Eo8 https://www.youtube.com/watch?v=rk6z1vP4Eo8

pfdietz 7y ago
I wouldn't believe that for a moment, and Google probably didn't either. It's interesting how the internet enables wishful thinking like this. You'd have thought the dearth of peer reviewed papers about Polywell would have been a clue, but true believers admit no impediment to their belief. There are good theoretical reasons to believe IEC fusion cannot work on advanced fuels, reasons that HAVE appeared in the peer reviewed literature.
- carapace 7y ago
  Absence of evidence is not evidence of absence. Would it be so terrible to do a little more research? If only to honor Dr Bussard's (RIP) memory? Google's not hurting for cash right now? "When a physicist tells you something is possible you should believe him, when a physicist tells you something is impossible you should doubt him." I forget who said that, but it holds. Lots of things had "good theoretical reasons" for not working until someone figured out how. Planes? Visiting the Moon?
  - pfdietz 7y ago
    Absence of evidence is evidence of shenanigans. If someone is making a claim, especially a remarkable claim, it is their responsibility to provide evidence for their claim. If they cannot, or if their evidence is such that it cannot pass peer review, something stinks, and one should be highly skeptical. This is not a case of "no one has shown X, therefore X should be dismissed". It's "P has claimed X, but has not shown evidence to justify their claim, therefore their claim should not be believed." If someone holds a position, presumably they had a good reason to do that, and one can ask for that reasoning and evidence (and ask that that reasoning and evidence be verified by peer review.)

peteretep 7y ago

With renewables getting better every day, at what point will they make fusion reactors irrelevant?

theothermkn 7y ago
Saul Griffith has an old talk entitled "Climate Change Recalculated." The gist is that he converts everyday energy consumption into averaged watts over a day, and then looks at the energy area density of renewables. The resulting picture is rather daunting. If we go 100% renewable--If we even could!--all of our lifestyles would be radically curtailed, and this is after a construction binge of enormous scale. We absolutely need fission and/or fusion. Of this there is no doubt.
- pfdietz 7y ago
  Yeah, that's bullshit. Energy density of renewables doesn't preclude current lifestyles. The Earth is constantly hit by 100,000 TW of sunlight, and the energy collected doesn't have to be used near where the collectors are.
  - serioussecurity 7y ago
    Density in this case referring to "kW per acre of solar panels", and the #s come out to something like covering all of Australia with solar panels, if I remember correctly.
    - peteretep 7y ago
      > and the #s come out to something like covering all of Australia with solar panels, if I remember correctly You do not remember correctly. Estimates seem to vary, but Musk reckons 100 miles by 100 miles for America[0] which I make as 0.003% of Australia. It's a large (if imaginary) place. [0] https://futurism.com/elon-musk-tells-national-governors-association-how-we-could-power-the-u-s-with-solar https://futurism.com/elon-musk-tells-national-governors-asso...

xchaotic 7y ago

What I find particularly troubling about the design of tokamak reactors is that on one hand you have magnets that need to be cooled to -250C or whatever the “high” temperature is nowadays and in the middle of it you have plasma that will leak thermal radiation in any way possible. The magnets themselves will heat up from running large electric currents through them. This just feels like a recipe for a disaster - if things suddenly stop working, due to heat or otherwise you have a very hot, radioactive plasma trying to equalise its energy with the outer world...

theothermkn 7y ago
Well, there's kind of a chain of intuitions here that are off by up to orders of magnitude. First, YBCO has a critical temperature of 93K, not 23K or so as you've suggested (albeit not as a value for YBCO). In other words, there have been advances in high temperature superconductors. Second, the magnets will not heat up from having large currents running through them. This is the point of superconductors. So, this estimate of resistivity is high by several orders of magnitude. Third, any estimate of the total energy of the hot plasma that gets us anywhere near verbiage hinting at explosions is too high by several orders of magnitude. You could typically extinguish a burning plasma by blowing gently on it. Finally, the thermal gradients aren't nearly so dire as, you know, 200e6K immediately next to 90K. There is typically over a meter of, in order: near-vacuum; inner wall; flowing lithium blanket; outer wall; and liquid nitrogen or other cryogenic coolant, all between the plasma and the magnets. This is the farthest thing from a recipe for disaster.
- grogers 7y ago
  Just want to point out that specific critical temperature varies with magnetic field. The article mentions 12T and 20K so presumably that is within some reasonable safety margin of the limit for YBCO at that field strength.

Swivekth18 7y ago

SPARC is an HTS experiment, showing the viability of compact Q>1 using the technology, showing you don't have to be ITER -size to have successful fusion. It doesn't claim to be and won't be much more than that. An important step, nonetheless.