[HN Gopher] Proxima Fusion looks to take stellarators commercial
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Proxima Fusion looks to take stellarators commercial
Author : mpweiher
Score : 67 points
Date : 2023-11-03 11:14 UTC (11 hours ago)
(HTM) web link (www.theengineer.co.uk)
(TXT) w3m dump (www.theengineer.co.uk)
| doctorhandshake wrote:
| Stellarators are one of those things where the visual complexity
| tells some basic part of my brain that 'this can't be the real
| thing'. Simplicity bias, I guess.
| phkx wrote:
| You can get a free guided tour at the Greifswald site of the
| IPP in the north of Germany to convince yourself of the
| physical reality.
|
| https://www.ipp.mpg.de/visitors
| doctorhandshake wrote:
| Man that sounds cool. To clarify, I meant "that looks too
| complex to be the 'right' answer".
| phkx wrote:
| Got it. Yeah, some intuition would make you think that the
| problem is somehow symmetrical, since other electromagnetic
| systems don't have this ,organic' kind of shape.
| pgeorgi wrote:
| Symmetrical except for gravity that always points
| downwards. I wonder if it's easier to pull off fusion in
| a (close to) zero gravity environment because the plasma
| doesn't budge by other effects than the container's.
| doctorhandshake wrote:
| I can only imagine taking one factor out can't hurt
| itishappy wrote:
| It is, it's just rotational instead of mirror symmetry.
| Check out some of the images further down this page:
|
| https://en.wikipedia.org/wiki/Stellarator
|
| My understanding is that the different sections of the
| torus experience different forces (inside vs outside due
| to the varying radii, top vs bottom due to gravity),
| which the Stellarator design attempts to compensate for
| by twisting the plasma so that no particular clump spends
| all of it's time in the same section.
|
| > The basic concept was a way to modify the torus layout
| so that it addressed Fermi's concerns though the device's
| geometry. By twisting one end of the torus compared to
| the other, forming a figure-8 layout instead of a circle,
| the magnetic lines no longer travelled around the tube at
| a constant radius, instead they moved closer and further
| from the torus' center. A particle orbiting these lines
| would find itself constantly moving in and out across the
| minor axis of the torus. The drift upward while it
| travelled through one section of the reactor would be
| reversed after half an orbit and it would drift downward
| again. The cancellation was not perfect, but it appeared
| this would so greatly reduce the net drift rates that the
| fuel would remain trapped long enough to heat it to the
| required temperatures.
| mpweiher wrote:
| The thing is: the complexity of the device translates into
| simplicity of the plasma. And vice versa.
|
| Tokamaks are nigh impossible to control.
|
| Stellarators, if you can build them, just hum along.
|
| And Wendelstein-7X proved that, though tricky, we can build
| them. Oh, and that the humming-along part is actually true.
|
| Last I checked, the maximum time for a Tokamak is 30s so
| far, Wendelstein has already achieved 8 minutes and they're
| shooting for 30 minutes.
| namuol wrote:
| What's the big trade off then? As I understand it there's
| more funding in tokamak research.
| mousetree wrote:
| Have you visited? Recommend? This looks very interesting. I
| think I might take a drive up there sometime.
| HPsquared wrote:
| I get that feeling looking at CPU die images.
| adhesive_wombat wrote:
| Especially when you consider that the image is a top-down
| view of dozens of layers and contains billions of
| connections. Amazing it works at all. And then consider it
| can be yours for something on the order of between an hour's
| and a day's income. Or, for one a few years old, practically
| free.
| tnecniv wrote:
| It's a trade off. Crazy geometry to try and make the physics of
| the plasma less crazy. At least that's my understanding from my
| friends who study plasma physics
| doctorhandshake wrote:
| Yeah it almost looks like something where the geometry is the
| result of trial and error rather than first principles
| design. Like 'whoops hit the side again lemme put a magnet
| there' x 10e4
| rcxdude wrote:
| That is basically what it is: it's the result of running an
| optimisation algorithm.
| Tade0 wrote:
| When I first saw a picture of the Wendelstein 7-X I could not
| make sense of it - it was really like some kind of alien
| artifact.
|
| And when you think what it actually does then 50 years ago,
| back when they were merely a concept, it could have passed as
| one.
| scotty79 wrote:
| I think humans have very limited capacity for reconstruction
| of 3d object from 2d image for anything beyond basic shapes
| or something they encountered extensively in real world.
|
| Viewing 3d model of 7-X might be easier to comprehend.
| phkx wrote:
| Quickly skimming over the links from your profile, I'm
| surprised that the non-reality of things might be a challenge
| to your brain. Cool stuff, will check it out more deeply.
| doctorhandshake wrote:
| Ha yeah nothing approaching the mind-shattering complexity
| that produces something as alien looking as a captured and
| suspended donut of sun-stuff.
| Syzygies wrote:
| How about the visual complexity of the coronavirus?
|
| Of course, you could challenge its effectiveness, too. London
| ended its cholera epidemic by no longer drinking sewer water.
| We still don't vent our buildings properly.
| creer wrote:
| Elegance is an engineering trope. But perhaps by now, it's just
| convenient. Engineering has gotten very good at managing
| complexity.
|
| See production machines like stealth fighters, relay-and-rotor-
| age pinball machines, military submarines, navigation or
| gunnery mechanical calculators, large construction projects...
| Some generations of CPUs are elegant in their return to first
| principles while others throw in everything but the kitchen
| sink in an unholy mess; Mainframe manufacturing is a gorgeous
| history of containing and organizing chaos. Fusion research
| machines are very complex, yes, but by this point... it's only
| so much of an obstacle.
|
| We might be tempted to throw in software ... Eh, perhaps we are
| not all that good with that yet. I mean, plenty of complexity,
| but not yet all that much "managed complexity".
| api wrote:
| Who says the stellarator isn't elegant?
|
| What I see when I look at it is something where the math is
| probably quite elegant. Fractals are simple mathematical
| expressions that generate outputs that appear to have
| infinite complexity.
| santiagobasulto wrote:
| $7m doesn't seem much for such a challenging project. How close
| are they to make this a reality?
| sigmoid10 wrote:
| Not close. This amount of money will get you some theoretical
| modelling at best, which is still nice because stellarators are
| infinitely more complex than tokamaks. The real hope here is
| that they _might_ solve the plasma instability problem of
| tokamaks, but the full picture isn 't out yet. In any case,
| we're very far from a commercial stellarator.
| mpweiher wrote:
| Er, they've solved the instability problem of tokamaks.
| They've already run it for 8 minutes, target is 30 and there
| don't seem to be any fundamental hurdles, just stuff to do to
| get there.
|
| https://www.ipp.mpg.de/5322229/01_23?c=5322195
| willis936 wrote:
| Indeed it's not. It's a similar level that Type One has
| received for a demonstration turn of a coil.
| otikik wrote:
| It is "peanuts". If that's the kind of investment it would take
| to make this a reality everyone and their aunt would have one.
| pgeorgi wrote:
| (Some in) the Greifswald team seem to estimate that it takes
| ~EUR20bn for a commercial deployment based on Wendelstein 7-X
| (according to a blogger who went there to ask:
| https://blog.fefe.de/?ts=9a9561ab)
| Y_Y wrote:
| Their "goal" is an order of magnitude improvement on existing
| stellarators, that sounds to me like it will want billions rather
| than millions. It's also doesn't seem to meet the "triple product
| Lawson criterion" for useful fusion (achieved recently at NIF,
| expected for ITER). This is cool, but I'm always skeptical of the
| viability of fusion startups. I won't name names, but there's
| already a couple out there that seem to me to be vapourware but
| are dragging in big funding based on the dream of fusion.
| boxed wrote:
| NIF didn't have anything even remotely practical though. The
| energy loss in the lasers alone is game over.
| Y_Y wrote:
| Exactly. They showed that it's a very lofty target even for a
| collosal non-commercial effort.
| itishappy wrote:
| It's a fair critique, but it was also never the intent. It
| was designed to test nuclear physics, not generate power.
| cameldrv wrote:
| It's a reasonable misunderstanding though. They pretty
| deliberately obscure this fact.
| itishappy wrote:
| I think they've been quite clear on their goals and
| accomplishments. Do you have an example in mind?
| boxed wrote:
| The big press releases claiming it has implications for
| fusion?
| itishappy wrote:
| This one?
|
| https://www.llnl.gov/article/49301/shot-ages-fusion-
| ignition...
|
| What do you find misleading? The ability to study self
| sustaining fusion reactions without nukes certainly does
| have implications for fusion, which aligns with their
| stated goals of researching nuclear physics.
| throwawaymaths wrote:
| What is misleading is that nowhere in the press release
| do they say:
|
| 1) this research is weapons research (much less primarily
| weapons over power research)
|
| 2) this research does not currently contend a viable
| avenue towards breakeven power generation
| itishappy wrote:
| > DOE Under Secretary for Nuclear Security and NNSA
| Administrator Jill Hruby said in achieving ignition, LLNL
| researchers have "opened a new chapter in NNSA's science-
| based Stockpile Stewardship Program," one that enables
| scientists to modernize nuclear weapons and explore new
| avenues of research in nuclear science.
|
| > Following Hruby, NNSA Deputy Administrator for Defense
| Programs Marvin "Marv" Adams showed a NIF target capsule
| and explained the science behind fusion reactions. Adams
| said ignition will enhance national security by helping
| NNSA maintain confidence in the nuclear deterrent,
| advance the country's non-proliferation goals and
| increase national security.
|
| > "The science and technology challenges on the path to
| fusion energy are daunting but making the seemingly
| impossible possible is when we're at our very best,"
| Budil explained. "Ignition is a first step -- a truly
| monumental one that sets the stage for a transformational
| decade in high energy density science and fusion research
| -- and I cannot wait to see where it takes us."
|
| > While optimism reigned for the event, Budil cautioned
| there are still "significant hurdles" and engineering
| challenges to solve before the commercialization of
| fusion energy becomes a reality, such as the ability to
| reproduce ignition many times per minute and making
| fusion reactions simpler and more efficient.
|
| > "I think it's moving into the foreground and, probably
| with concerted effort and investment, a few decades of
| research on the underlying technologies could put us in a
| position to build a power plant," Budil said.
| throwawaymaths wrote:
| > the seemingly impossible possible
|
| Did anyone seriously believe it was impossible to get "q"
| > 1 fusion by blasting a pellet of hydrogen hard enough?
|
| ---
|
| Significant hurdles != "There is not currently a/no known
| path"
|
| I'm still toning down from "a path is impossible" which
| ought to be the consensus.
|
| > a few decades of research on the underlying
| technologies could put us in a position to build a power
| plant
|
| No.
| cameldrv wrote:
| From that press release:
|
| > Granholm added that the unprecedented accomplishment
| will strengthen national security and moves the world
| closer to the possibility of an abundant, carbon-free
| energy source for the future.
|
| > "It would be like adding a power drill to our toolbox
| for building a clean-energy economy," Granholm said.
| "Today, we tell the world: America has achieved a
| tremendous scientific breakthrough -- one that happened
| because we invested in our national labs and fundamental
| research. And tomorrow, we will continue to work toward a
| future powered in part by fusion energy."
|
| Since the start of the program they have been promoting
| ICF as a method of power generation. The very fact that
| they're crowing about net energy gain is because a
| minimum requirement for a power plant is that the energy
| that comes out has to be more than the energy that goes
| in. This is not a requirement for a fusion research
| machine.
| throwawaymaths wrote:
| Since we're on the topic of "dragging in big funding
| based on the dream of fusion", can you point to a press
| release where they explicitly mention that this research
| is for weapons research and not for power research?
| itishappy wrote:
| Have you checked their website?
|
| > MAINTAINING THE NUCLEAR DETERRENT
|
| > Stockpile Stewardship
|
| > NIF is a key element of the National Nuclear Security
| Administration's science-based Stockpile Stewardship
| Program to maintain the reliability, security, and safety
| of the U.S. nuclear deterrent without full-scale testing.
|
| https://lasers.llnl.gov/about/what-is-nif
|
| > For more than 70 years, Lawrence Livermore National
| Laboratory has applied science and technology (S&T) to
| make the world a safer place. While keeping our crucial
| mission-driven commitments in mind, we apply cutting-edge
| science and technology to achieve breakthroughs in
| nuclear deterrence, counterterrorism and
| nonproliferation, defense and intelligence and energy and
| environmental security.
|
| https://www.llnl.gov/
|
| It's also intended for energy research, but there's an
| important distinction between "energy research" and
| "energy production."
| throwawaymaths wrote:
| Website != Press release
| firedaemon wrote:
| At this point the claim seems to be _but I think that
| some people think it is all about energy_ , as if your
| random interpretation of other peoples' belief is
| relevant.
|
| They do weapons. They said they do weapons. What's the
| problem.
| ben_w wrote:
| IIRC, that specific issue is merely an implementation detail,
| much more efficient lasers already exist.
|
| There are plenty of other problems to be solved, and a lot of
| room for higher gain -- upgrading the lasers isn't worth
| caring about until those things have actually been done.
| boxed wrote:
| The efficiency in the lasers isn't off by 50%. They are off
| by SEVERAL orders of magnitude.
|
| Plus the fuel pellets are too expensive anyway.
| ben_w wrote:
| Yes, I know.
|
| NIF's lasers are, I'm told, less than 1% efficient;
| modern lasers can be 50%-80% if that's what is being
| optimised for.
|
| There's no reason to bother upgrading those lasers until
| all the other issues are solved, and even then, as it's
| an experimental facility not a power station, they may
| well _never_ bother even if it is the only thing holding
| them back from a gain of more than 1 as measured
| wallplug-to-wallplug.
| maxcan wrote:
| True. But if you replace the Hohlraum with dilithium and find
| an anti-matter supply you can power a warm drive for FTL
| travel. Just need to kick it now and then.
| DennisP wrote:
| They lose so much in the lasers because they're using lasers
| from the 1990s, which are only 0.5% efficient. Equivalent
| modern lasers are over 20% efficient. From the input power
| being 130X more than the fusion output, modern lasers would
| turn that into about 3X.
|
| That's kinda promising because the fusion output seems to
| have nonlinear scaling; they increased laser power 8% and got
| 230% more output.
|
| This is why there are startups now pursuing laser fusion for
| commercial energy.
| willis936 wrote:
| Triple product is necessary and partially sufficient. One of
| those products is "confinement time". Longer confinement times
| with lower density make for machines that are closer to steady
| state rather than pulsed, greatly reducing engineering
| challenges. Stellarators are on the far end of the "steady
| state" spectrum while NIF is on the far end of the "high
| density" spectrum.
| BeefWellington wrote:
| I look at these places as technology and patent incubators more
| than anything.
| danbruc wrote:
| NIF is doing weapons research, what they achieved is
| essentially irrelevant for electricity production as there is
| no plausible route towards a power plant. And if you take the
| overall energy balance, they did not even break even.
| cmpxchg8b wrote:
| Warships need electricity too..
| Symmetry wrote:
| And the Navy puts money into fusion research for that
| reason, including a bit into cold fusion just in case. But
| that's not what their doing at NIF, those guys are trying
| to figure out if you can make a thermonuclear bomb with
| just cheap lithium deutride and not the expensive
| plutonium/enriched uranium.
| tivert wrote:
| > But that's not what their doing at NIF, those guys are
| trying to figure out if you can make a thermonuclear bomb
| with just cheap lithium deutride and not the expensive
| plutonium/enriched uranium.
|
| IIRC, thermonuclear bombs are already made with lithium
| deutride.
|
| Do you mean they're trying to build a thermonuclear bomb
| without the fission "detonator"? That doesn't make tons
| of sense to me, since I'd think the test ban treaty would
| realistically prevent creation of novel types of weapons
| (because it wouldn't be foolish to rely on a weapon for
| deterrence that you've never fully tested).
| actionfromafar wrote:
| The treaty Russia just punted on?
| danbruc wrote:
| The one that the United States signed but never ratified?
| Just as China, Egypt, Iran and Israel. And that India,
| North Korea and Pakistan never signed to begin with? And
| that will enter into force only after all those countries
| have signed at ratified it?
| noobermin wrote:
| I'm freaking tired of this line. NIF has an actual break even
| result which is greater than the results of any mcf
| experiment. If the NIF result is shit that whole field's
| result is then below shit.
| danbruc wrote:
| Already the first fusion bomb had a break even result.
| dreamcompiler wrote:
| NIF's result is significant milestone in the same sense
| that the invention of the airplane was a significant
| milestone in the field of space travel. It matters, but
| we're still a very, _very_ long way from landing on the
| moon (a fusion-powered electric grid).
| jmyeet wrote:
| I fully support more research into commercial fusion power
| eneration. I really hope it becomes economical. That being said,
| I'm not convinced this will ever happen for these reasons:
|
| 1. Energy loss from neutron loss. So-called "aneutronic fusion"
| seeks to avoid this problem but requires rare fuels (eg He-3),
| which kind of defeats the point. Also, it's not neutron free.
| It's just fewer neutrons;
|
| 2. Container destruction from neutrons (ie "neutron
| embrittlement"); and
|
| 3. A superheated plasma (in either a tokamak or stellerator) is
| fundamentally a turbulent fluid. This is inherently unstable. Any
| imperfection in the containment could result in significant
| container damage.
|
| Fusion works for stars because fusion is relatively slow (on a
| per-unit mass basis, which is why stars can live billions or evne
| trillions of years) and they have gravity for neutron
| containment.
|
| More on the difference to tokamaks [1].
|
| [1]:
| https://www.sciencedirect.com/science/article/pii/S2468080X1...
| willis936 wrote:
| >This is inherently unstable. Any imperfection in the
| containment could result in significant container damage.
|
| This is a misunderstanding that conflates multiple concepts:
| instabilities from toroidal plasma current (unnecessary in
| stellarators) and edge turbulence (lower confinement time).
| W7-X has done 30 second shots and are working their way to 30
| minute shots. It is their control that has terminated their
| shots, not the plasma.
| jmyeet wrote:
| You're trying to contain something at ~100 million degrees
| when the result of that process is destroying the container.
| It's not an exaggeration to say the engineering challenges
| are... significant.
| willis936 wrote:
| Indeed it is and the details matter. That's why I wanted to
| set the record straight.
| mpweiher wrote:
| Yep. It's hard. That's why stellarators are so amazing:
| they can do it.
| DennisP wrote:
| The temperature is high but the amount of heat isn't
| unusual. The atoms are moving fast but there aren't many of
| them. For a 500MW plant you're containing about the same
| amount of energy whether it's fusion or coal.
| mpweiher wrote:
| Exactly!
|
| Update:
|
| > W7-X has done 30 second shots
|
| They're up to 8 minutes now.
|
| https://www.ipp.mpg.de/5322229/01_23?c=5322195
| automatic6131 wrote:
| >gravity for neutron containment.
|
| Is it gravity, or is it gigameters of nuclei in every
| direction?
| falseprofit wrote:
| you think that high pressure material would just sit there in
| space, absent gravity?
| adrianN wrote:
| How much damage can a few grams of gas do to a massive reactor
| vessel?
| ben_w wrote:
| Gas? Not much. 14 grams of D-D fusion byproduct plasma? This
| much damage: https://www.youtube.com/shorts/wqKn_3iJOP4 (I
| chose 14 grams to make it the same).
|
| While it's ridiculously difficult for fusion to go off like
| that, even spreading that same energy over 2.488 hours (for a
| nice 1 GW-thermal reactor) leaves you with the problem that
| it is in the form of high energy radiation that's more than
| strong enough to knock atoms out of their latices.
| adrianN wrote:
| Hm, the fusion plasma would rapidly cool and stop fusing as
| soon as containment fails. I don't see how a few grams of
| very hot gas can do more that a little scratch to a reactor
| wall that is designed to be bombarded by radiation and
| carry off megawatts of power to a steam turbine.
| ben_w wrote:
| I suspect there are multiple PhDs each focussed entirely
| on one aspect of the problem of damage from the fusion
| plasma. The example I gave, of atoms being knocked from
| their lattices? I only know about that because of meeting
| someone in an infamous Cambridge geek pub who was working
| on it.
| DennisP wrote:
| In a D-T reactor you're not losing energy from neutrons, you're
| using the neutrons to heat a coolant and turn a turbine. (And
| also to breed more tritium, but that still generates heat.)
|
| He3 is rare but deuterium is decidedly not. Fusion deuterium is
| about as easy as fusing He3, and the waste product of D-D is
| half He3, and half tritium which decays to He3 with a 12-year
| half-life.
|
| Fusion company Helion is building a hybrid D-D/D-He3, and says
| the combination would release only 5% of its energy as neutron
| radiation, compared to 80% from D-T. The neutrons would also
| have lower energy, below the activation energy of common
| reactor materials.
| pshirshov wrote:
| Once, when I was a schoolboy, I walked along this thingy:
| https://www.inp.nsk.su/~dep_plasma/img/GOL3.jpg and the guide
| told us that a couple of millions USD would let them build a
| working commercial fusion machine. I've heard many news like that
| since then, so I'm extremely skeptic.
| anonuser123456 wrote:
| Any DT fusion proposal that doesn't start with how they plan to
| breed and capture tritium is a dead end.
| denton-scratch wrote:
| TFA doesn't say what a "stellarator" is.
|
| https://en.wikipedia.org/wiki/Stellarator
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