[HN Gopher] Progress toward fusion energy gain as measured again...
___________________________________________________________________
Progress toward fusion energy gain as measured against the Lawson
criteria
Author : sam
Score : 226 points
Date : 2025-05-08 15:49 UTC (1 days ago)
(HTM) web link (www.fusionenergybase.com)
(TXT) w3m dump (www.fusionenergybase.com)
| actinium226 wrote:
| Why is the last plot basically empty between 2000 and 2020? I
| understand that NIF was probably being built during that time,
| but were there no significant tokamak experiments in that time?
| 7thaccount wrote:
| I imagine a 20 year gap isn't too crazy for a field like
| fusion, but you've made me curious as well.
| tomnicholas1 wrote:
| Presumably because everyone in MCF has been waiting for ITER
| for decades, and JET is being decommissioned after a last gasp.
| Every other tokamak is considerably smaller (or similar size
| like DIII-D or JT-60SA).
|
| Much of the interesting tokamak engineering ideas were on small
| (so low-power) machines or just concepts using high-temperature
| superconducting magnets.
| moffkalast wrote:
| It's hard to believe that after all of this time, ITER is
| still almost a decade away from first plasma.
|
| There's the common joke that fusion is always 30 years away,
| but now with the help of ITER, it's always 10 years away
| instead.
| tomnicholas1 wrote:
| The really depressing part is if you plot rate of new
| delays against real time elapsed, the projected finishing
| date is even further.
|
| This is why much of the fusion research community feel
| disillusioned with ITER, and so are more interested in
| these smaller (and supposedly more "agile") machines with
| high-temperature superconductors instead.
| cyberax wrote:
| The ITER is in development hell.
|
| Mind you, it's not useless! It produced a TON of very useful
| fusion research: neutral beam injectors, divertors,
| construction techniques for complex vacuum chambers, etc. At
| this point, I don't think it's going to be complete by the time
| its competitors arrive.
|
| One spinoff of this is high-temperature superconductor research
| that is now close to producing actually usable high-TC flexible
| tapes. This might make it possible to have cheaper MRI and NMR
| machines, and probably a lot of other innovations.
| pfdietz wrote:
| ITER doesn't use high temperature superconductors. It uses
| niobium-tin and niobium-titanium low temperature
| superconductors in its magnets.
|
| ITER has been criticized since early days as a dead end, for
| example because of its enormous size relative to the power
| produced. A commercial follow-on would not be much better by
| that power density metric, certainly far worse than a fission
| reactor.
|
| There is basically no chance than a fusion reactor operating
| in a regime similar to ITER could ever become an economical
| energy source. And this has been known since the beginning.
|
| I call things like ITER "Blazing Saddles" projects. "We have
| to protect our phony baloney jobs, gentlemen!"
| robocat wrote:
| > phony baloney jobs
|
| I looked hopefully at the HR report https://www.iter.org/si
| tes/default/files/media/2024-11/rh-20... to see if there
| was some sort of job categorisation - scientist, engineer,
| management. Disappointingly scant. PhD heavy. Perhaps the
| budget would be more insightful.
|
| "Execution not ideas" is a common refrain for startups.
|
| I wonder how much of the real engineering for ITER is
| occurring in subcontractors?
| whatshisface wrote:
| I wonder why a physics research facility would be PhD-
| heavy. ;-)
| cyberax wrote:
| > ITER doesn't use high temperature superconductors.
|
| It does, for high-current buses that interface with regular
| resistive power distribution. They are also planned for
| some auxiliary components (like the neutral beam
| injectors).
|
| > ITER has been criticized since early days as a dead end,
| for example because of its enormous size relative to the
| power produced.
|
| ITER is NOT designed for power generation. It's essentially
| a lab experiment to see how plasma behaves in magnetic
| confinement and test various technologies.
|
| That's why ITER was designed with a very conservative
| approach to reduce the technical risk. We don't need it to
| be compact, this can come later. We just need it to work.
|
| And yes, it is necessary. Plasma behavior can't be
| simulated numerically or analytically. It always provides
| surprises, sometimes even good ones:
| https://en.wikipedia.org/wiki/High-confinement_mode
| pfdietz wrote:
| > ITER is NOT designed for power generation. It's
| essentially a lab experiment to see how plasma behaves in
| magnetic confinement and test various technologies.
|
| That's the go-to excuse. But if you look at DEMO, it's
| power density is not enormously greater. ITER is so far
| out of the running that DEMO (or PROTO, etc.) will be
| too.
|
| We're learning a great deal about something that's
| largely irrelevant.
| cyberax wrote:
| DEMO concept sketches are completely obsolete at this
| point. It's not going to look anything like this.
|
| They're based on the state-of-the art from about 2005.
| Since then, a lot of improvements happened. A more
| realistic power plant design is going to use a thinner
| center column (because of better superconducting
| magnets), resulting in a smaller cryostat volume.
| Possibly high-TC magnets.
|
| It can also be made more compact, if neutral beams can be
| used to suppress some plasma instabilities.
| Calwestjobs wrote:
| misunderstanding about ITER what you some people doing is
| that it is just one thing, it is not.
|
| ITER is not only facility in france it is multitude of
| manufacturing capabilities all over the globe which build
| parts for ITER and all future power plants.
| pfdietz wrote:
| It's my understanding that neutron wall loading of DEMO
| concepts had been trending _downward_ (due to materials
| limits), the opposite of the trend you 're trying to
| portray there. And in no future world is the power
| density of DEMO going to be anywhere close to that of a
| fission reactor.
| cyberax wrote:
| Neutron loading is not the limiting factor (for now),
| it's the magnetic field pressure and its homogeneity.
| That's actually what is driving the humongous size of the
| ITER.
|
| To solve the homogeneity problem, you need the central
| column to be as thin as possible. That's where a lot of
| the recent advancements can help.
|
| Also, fission research and fusion are actually aligned in
| designing materials that can tolerate more displacements
| per atom.
|
| > And in no future world is the power density of DEMO
| going to be anywhere close to that of a fission reactor.
|
| That's for sure. Modern fission reactors are close to
| magic, with the amount of heat they produce for a given
| volume.
| pfdietz wrote:
| However, if neutron loading has gone down, and the
| reactor is the same size, the volumetric power density
| must also have gone down.
|
| The comment about fission and neutron dpa is misleading.
| The neutron damage issue is _much_ less bothersome in
| fission reactors.
|
| Fission produces about 3% of its energy in neutrons, vs.
| 80% in the DT fusion reaction. The spectrum of fission
| neutrons is much softer, with a peak around 1 Mev, vs. 14
| MeV for DT neutrons. The DT neutrons are above threshold
| for (n,2n) reactions in most materials, and have much
| higher cross section for (n,p) and (n,alpha) reactions.
| The latter is particularly troublesome, as helium
| accumulates inside materials, forming microscopic very
| high pressure bubbles that rip the materials apart.
|
| But it's even comparatively worse for fusion than that.
| In a PWR (for example), the core is carefully designed so
| that the only parts exposed to unmoderated neutrons are
| the fuel rods and the replaceable parts of the fuel rod
| bundles. The latter provide structural support for the
| fuel rods and are removed along with the fuel rods when
| the fuel is spent. The actual core supports for the fuel
| bundles are well away from where the chain reaction is
| occurring, shielded by water. The mean free path of a
| fission neutron in water is just a few centimeters, so
| their energy is quickly dissipated before reaching these
| components.
|
| So, exposure of permanent reactor components to fast
| neutrons is essentially a non-issue in PWRs. Even control
| rods are not exposed much; reactivity is controlled by
| boric acid dissolved in the water (BWRs do it somewhat
| differently.)
|
| This same strategy cannot be used in a fusion reactor;
| the plasma facing surfaces are exposed to the full,
| unshielded brunt of the DT neutron flux. _Maybe_ a few cm
| of liquid lithium could be flowed along some surfaces?
| This is a stretch, particularly in a toroidal reactor.
| adgjlsfhk1 wrote:
| is a conservative approach useful if it is taking 30
| years to build?
| myrmidon wrote:
| > I call things like ITER "Blazing Saddles" projects. "We
| have to protect our phony baloney jobs, gentlemen!"
|
| I think this is overly harsh and somewhat unfair. You could
| make the same argument that anything operating in a regime
| similar to the Chicago Pile 1 could never be an economical
| reactor _nor_ a bomb, but that does not mean skipping that
| particular development step is viable.
|
| As far as fusion reporting goes, articles are at least
| somewhat consistent on the fact that ITER is a pure
| research project/reactor, while every 10-man fusion startup
| is being hyped up beyond all reason even if there is not
| even a credible roadmap towards an actual reactor in the
| 100MW range at all.
|
| Personally I don't see fusion being a mainstream energy
| source (or helpful against climate change) in this century
| at all and maybe never, but ITER (even with all the delays)
| is at least an honest attempt at a credible size, and being
| stuck on older technology is an unfortunate side-effect of
| that.
| pfdietz wrote:
| I don't think it's unfair at all. And I don't see ITER as
| an "honest attempt", far from it.
|
| The initial cost figures for ITER were obviously
| deliberate lies. When the true costs inevitably came out
| (after commitment had been made) this led to alternative
| approaches being canned. ITER has done grievous damage to
| fusion as a field, in a way eerily similar to how the
| Space Shuttle and ISS have done damage to NASA.
|
| The true purpose of ITER wasn't to achieve fusion or push
| forward fusion; it was to preserve funding until those
| making the decisions had retired. If this required
| sacrificing long term goals, like actually delivering
| competitive energy (or, really, delivering anything at
| all), so be it.
| myrmidon wrote:
| As an engineer, the difference between "deliberate lies"
| and "overoptimistic estimates" is often just in the eye
| of the beholder; Hanlons Razor should be applied IMO.
|
| Was ITER overambitious? Timeline and budget unrealistic
| from the start? Maybe. But I'm fairly confident that most
| people involved had perfectly defensible intentions.
|
| I also think that if the goal is commercial fusion, small
| reactors (100MW and below) are nothing but a stepping
| stone and inherently commercially useless; I don't see
| the output (hundreds of termal megawatts) _ever_
| justifying the "fixed" overhead costs, and a scale at
| least close to GW scale seems completely inevitable to
| me.
|
| If you agree with that premise, then building a reactor
| that size has a lot of utility already that you'd never
| achieve from building Wendelstein 7x equivalents or
| whatever at 50 different university campuses (or however
| else you'd want to spend the funds instead).
|
| > The true purpose of ITER wasn't to achieve fusion or
| push forward fusion; it was to preserve funding until
| those making the decisions had retired. If this required
| sacrificing long term goals, like actually delivering
| competitive energy (or, really, delivering anything at
| all), so be it.
|
| This is what I most disagree with; if commercial fusion
| is viable (I believe it really isn't) then I think ITER
| (or an equivalent of its size) is a very necessary, if
| expensive, step to make, and spending the money on dozens
| of smaller projects is not an "obviously better long term
| approach" at all in my view.
|
| I also think that speaking about "true purpose" of the
| whole project is personifying the output of a complex
| process way too much, where individual actors in that
| scheme just want to make ITER _happen_ (for very
| defensible reasons IMO).
| cobbzilla wrote:
| conceptually sure; but size-wise they are so different as
| to warrant valid questions about ROI.
|
| Chicago Pile 1 ran for 12 years, ITER started ~12 years
| ago and plans to run into the 2030s at least. Budget and
| headcount would likely be vastly different too, I'd
| welcome any educated guesses. Sometimes quantity has a
| quality of its own, as they say.
| myrmidon wrote:
| Sure but those are not really equivalent/comparable in
| scale; just looking at power/size and conceptual distance
| from commercial viability, the Chicago pile does not even
| match up to something like SPARC or JET, much less ITER.
|
| A more fitting comparison to ITER would be something like
| Fermi-1 or other prototype designs at almost commercial
| scale, IMO, and those were multi-year, large projects too
| (and fission is much simpler than fusion, which obviously
| also helps).
| pfdietz wrote:
| The X-10 reactor at Argonne went critical less than a
| year after CP-1, with a power of 500 kW, rising to 4 MW
| in 1944. The Hanford B reactor, with a power of 250 MW,
| was in operation less than two years after CP-1 went
| critical.
| jabl wrote:
| > actually usable high-TC flexible tapes. This might make it
| possible to have cheaper MRI and NMR machines, and probably a
| lot of other innovations.
|
| I'm sure there'll be plenty of fascinating applications of
| high-Tc tape, however I'm not sure MRI/NMR machines will be
| one of those. There would still be a lot of thermal noise due
| to the high temperature. Which is why MRI/NMR machines tend
| to use liquid helium cooling, not because superconductors
| capable of operating at higher temperatures don't exist.
| sam wrote:
| Author here - some other posters have touched on the reasons.
| Much of the focus on high performing tokamaks shifted to ITER
| in recent decades, though this is now changing as fusion
| companies are utilizing new enabling technologies like high-
| temperature superconductors.
|
| Additionally the final plot of scientific gain (Qsci) vs time
| effectively requires the use of deuterium-tritium fuel to
| generate the amounts of fusion energy needed for an appreciable
| level of Qsci. The number of tokamak experiments utilizing
| deuterium tritium is small.
| CGMthrowaway wrote:
| If ITER is where it's at why are we building commercial scale
| tokamak?
| https://en.wikipedia.org/wiki/Commonwealth_Fusion_Systems
| sam wrote:
| Companies like Commonwealth Fusion Systems are an example
| of those utilizing high-temperature superconductors which
| did not exist commercially when ITER was being designed.
| twothreeone wrote:
| ITER uses HTSs, just not for the coils:
|
| > The design operating current of the feeders is 68Ka.
| High temperature superconductor (HTS) current leads
| transmit the high-power currents from the room-
| temperature power supplies to the low-temperature
| superconducting coils 4K (-269degC) with minimum heat
| load.
|
| Source: https://www.iter.org/machine/magnets
| stshank wrote:
| HTS current feeds are a good idea (we also use them at
| CFS, my employer:
| https://www.instagram.com/p/DJXInDUuDAK/). It's HTS in
| the coils (electromagnets) that enables higher magnetic
| fields and thus a more compact tokamak.
| satellite2 wrote:
| Thanks a lot for this research. Seing the comments here I
| think it's really important to make breakthroughs and
| progress more visible to the public. Otherwise the impression
| that "we're always 50 years away" stays strong.
|
| Here was my completely layman attempt to forecast fusion
| viability a few months ago.
| https://news.ycombinator.com/item?id=42791997 (in short:
| 2037)
|
| Is there some semblance of realism there you think?
| mchusma wrote:
| In the 2037 timeframe, modeling trends doesn't matter as
| much as looking at the actual players. I think odds are
| good because you have at least 4 very well funded groups
| shooting to have something before 2035: commercial groups
| including CFS, Helios, TAE, also the efforts by ITER. Maybe
| more. Each with generally independent approaches. I think
| scientific viability will be proven by 2035, but getting
| economic viability could take much longer.
| edran wrote:
| This is a great update! I hope the authors continue publishing
| new versions of their plots as the community builds up towards
| facility gain. It's hard to keep track of all the experiments
| going on around the world, and normalizing all the results into
| the same plot space (even wrt. just triple product / Lawson
| criteria) is actually tricky for various reasons and takes
| dedicated time.
|
| Somewhat relevant, folks here might also be interested in a
| whitepaper we recently put up on arXiv that describes what we are
| doing at Pacific Fusion: https://arxiv.org/abs/2504.10680
|
| Section 1 in particular gives some extra high-level context that
| might be useful to have while reading Sam and Scott's update, and
| the rest of the paper should also be a good introduction to the
| various subsystems that make up a high-yield fusion demonstration
| system (albeit focused on pulser-driven inertial fusion).
| arghandugh wrote:
| Maybe someday we'll finally achieve the ultimate dream: an
| extremely expensive nuclear power plant that needs vast amounts
| of coolant water and leaves radioactive waste behind.
| fecal_henge wrote:
| I see you're in the coolant business
| arghandugh wrote:
| I am in the business of baiting militantly uninformed
| enthusiasts who form the foundation of the multigenerational
| grift that is Commercial Fusion Power.
| BizarroLand wrote:
| Real talk, the point is not that whatever system is first past
| the post for fusion becomes the gold standard and fills the
| planet.
|
| The issue right now is cracking the code. Once that is done,
| performance gains and miniaturization can take place.
|
| Fusion can work on lots of things. Its possible that a fusion
| system the size of a car could be made within 25 years of the
| code being cracked that would power a house, or the size of a
| small building that could power a city block.
|
| The waste product of hydrogen fusion is helium, a valuable
| resource that will always be in high demand, and it will not be
| radioactive.
|
| And yes, it will need coolant as with hot fusion the system
| uses the heat to turn a turbine, but that coolant isn't fancy,
| it's just water.
|
| Fusion has the potential to solve more problems than it causes
| by every metric as long as it is doable without extremely
| limited source materials, and this is what these big expensive
| reactors are trying to solve.
| arghandugh wrote:
| You've disputed nothing I've said and unless a dramatically
| higher temperature fusion reaction that does not generate a
| neutron flux is achieved, it will generate radioactive waste
| as a matter of factual physics. Thank you though!
| BizarroLand wrote:
| I mean, yes, you're right, but it's not a permanently
| radioactive waste.
|
| Quote:
|
| A fusion power plant produces radioactive waste because the
| high-energy neutrons produced by fusion activate the walls
| of the plasma vessel. The intensity and duration of this
| activation depend on the material impinged on by the
| neutrons.
|
| The walls of the plasma vessel must be temporarily stored
| after the end of operation. This waste quantity is
| initially larger than that from nuclear fission plants.
| However, these are mainly low- and medium-level radioactive
| materials that pose a much lower risk to the environment
| and human health than high-level radioactive materials from
| fission power plants. The radiation from this fusion waste
| decreases significantly faster than that of high-level
| radioactive waste from fission power plants. Scientists are
| researching materials for wall components that allow for
| further reduction of activation. They are also developing
| recycling technologies through which all activated
| components of a fusion reactor can be released after some
| time or reused in new power plants. Currently, it can be
| assumed that recycling by remote handling could be started
| as early as one year after switching off a fusion power
| plant. Unlike nuclear fission reactors, the long term
| storage should not be required.
|
| https://www.ipp.mpg.de/2769068/faq9
|
| Basically, whatever containment vessel becomes standard for
| the whole fusion industry would need probably an annual
| cycle of vessel replacements, which would be recycled
| indefinitely and possibly mined for other useful
| radioactive byproducts in the process.
| greenavocado wrote:
| The amount of radioactive scrap produced by hypothetical
| decommissioned radioactive fusion containment vessels is
| laughably trivial compared to fission waste streams. Even
| accounting for the most pessimistic irradiation models of
| first-wall materials, the total radioactive burden
| remains orders of magnitude below legacy technologies.
| The half-lives of such activated components like
| predominantly steel alloys and ceramic composites trend
| dramatically shorter than actinide-laden spent fuel, with
| activity levels plummeting to background within mere
| decades rather than geological timescales. This makes
| waste management a single-generation engineering
| challenge rather than a multi-millennial obligation
| pfdietz wrote:
| The long term activity of the waste is certainly lower,
| but the _volume_ of the waste is likely much higher. And
| much of the cost is driven by volume, not activity.
| markvdb wrote:
| As a species, we're spectacularly bad at negative
| externalities.
|
| We are also very bad at anything very long term. We've
| hardly pulled off any physical project to last more than
| one generation recently. We barely invest in any.
|
| The winning energy tech of the future better have as
| little negative externalities as possible, especially
| long term ones.
| arghandugh wrote:
| Hey, there it is! Lots of radioactive waste being
| generated on a continuous business but maybe baby with
| dreams and creams we can decommission it with robots and
| recycle it all. Meanwhile a reactor is offline for
| refurbishment for days, weeks, months, blowing a hole in
| the economics of it all.
|
| Unironically: you're the first person I've come across to
| openly acknowledge this issue. Thank you.
| thinkingtoilet wrote:
| If the alternative option is a coal power plant, sign me up!
| arghandugh wrote:
| You will not live long enough to see commercial fusion power,
| and your children will not live long enough to see a complete
| end to thermal coal.
| sneak wrote:
| Tossing out your opinions as fact doesn't do much to win
| hearts and minds, or educate us bystanders to the basis for
| your point of view.
|
| Presumably your comment is either to persuade or to inform;
| it does neither. I'm very curious about this field and its
| future, do you care to try again?
| dale_glass wrote:
| I'm a different person, but I tend to agree.
|
| ITER began building in 2013, first plasma is expected for
| 2034. DEMO is expected to start in 2040.
|
| So, ITER is taking an estimated 20 years. It's being
| built for a reason, so I imagine follow-ups want to wait
| to see how that shakes out. So certainly, DEMO needs to
| start a few years after ITER is finally done.
|
| Then DEMO isn't a production setup either, it's going to
| be the first attempt at a working reactor. So let's say
| optimistically 20 years is enough to build DEMO, run it
| for a few years, see how it shakes out, design the
| follow-ups with the lessons learned.
|
| That means the first real, post-DEMO plant starts
| building somewhere in 2060. Yeah, fair to say a lot of
| the here present will be dead by then, and that'll only
| be the slow start of grid fusion if it sticks at all.
| Nobody is going to just go and build a hundred reactors
| at once. They'll be built slowly at first unless we
| somehow manage to start making them amazingly quickly and
| cheaply.
|
| So that's what, half a century? By the time fusion gets
| all the kinks worked out, chances are it'll never be
| commercially viable. Renewables are far faster to build,
| many problems are solvable by brute force, and half a
| century is a lot of time to invent something new in the
| area.
| arghandugh wrote:
| If Jesus Christ himself came to earth and hand delivered
| a durable and workable reactor design WITH high uptime
| WITH a near-optimal confinement scheme WITH zero
| neutronicity AND he included a decade of free perfectly
| packaged and purified fuel, it would still not pencil out
| as anything other than water-hungry staff-intensive
| baseload requiring significant state support.
|
| This is the reality. It's not happening. It's a welfare
| program for bullshit artists that depends on a credulous
| public.
| DennisP wrote:
| ITER/DEMO is an exceptionally slow fusion project and
| arguably obsolete since it uses older superconductors.
| CFS uses the same design, with modern superconductors
| that can support much stronger magnetic fields. Tokamak
| output scales with the fourth power of magnetic field
| strength, so this should let them get results similar to
| ITER in a reactor a tenth the size. They'll have it
| running long before ITER is ready.
| pfdietz wrote:
| ITER will have 400x lower power density than a PWR.
|
| ARC, which uses those high temperature superconductors,
| is just 40x lower power density.
|
| Neither promises to be competitive with fission, never
| mind the things beating fission.
| thinkingtoilet wrote:
| I don't see how your comment addresses what I said at all.
| triceratops wrote:
| I don't know I think thermal coal could end in my lifetime.
| adgjlsfhk1 wrote:
| coal is already very much on the way out. natural gas is
| much cheaper, and also greener.
| CGMthrowaway wrote:
| I heard that NIF was never intended to be a power plant, not even
| a prototype of one. It's primarily a nuclear weapon research
| program. For a power plant you would need much more efficient
| lasers, you would need a much larger gain in the capsules, you
| would need lasers that can do many shots per second, some
| automated reloading system for the capsules, and you would need a
| heat to electricity conversion system around the fusion spot
| (which will have an efficiency of ~1/3 or so).
|
| Any truth to that?
| DennisP wrote:
| It's an experimental facility. Yes, a power plant would need
| much more efficient lasers, but NIF's lasers date back to the
| 1990s, equivalent modern lasers are about 40X more efficient,
| and for an experiment it's easy enough to do a multiplication
| to see what the net result would have been with modern lasers.
|
| Modern lasers can also repeat shots much more quickly. Power
| gain on the capsules appears to scale faster than linear with
| the input power, so getting to practical gain might not be as
| far off as it appears at first glance.
|
| These are some of the reasons that various fusion startups are
| pursuing laser fusion for power plants.
| hinkley wrote:
| I was trying to work out a joke about buying better lasers
| off of alibaba but it seems that despite being 30 years old
| they're still orders of magnitude beyond off the shelf
| options.
| trhway wrote:
| partially. The very efficient lasers from alibaba don't
| have short pulse/high power, so they can potentially be
| used only as the part of the system - the pumping lasers.
| The final nanosecond-laser is still a one-off build which
| though seems to be pretty doable even by a small company if
| they set their mind to it.
|
| Btw, NIF achieved those recent results by adding strong
| magnetic field around the target (penny-shrinkers knew that
| tech for 20+ years :). There are other things like this
| around that can potentially be similarly useful. Only if
| somebody had money and interest ...
| DennisP wrote:
| Lots of people do have money and interest:
| https://archive.is/BCsf5
| hinkley wrote:
| I've seen some pretty wacky structures that involve
| mechanically forcing permanent magnets together at
| different orientations to create assymetric magnetic
| fields that are strongest where they need to be or weak
| where they would cause problems. Like eddy currents in
| electric motor housing, or insufficient hold for chef's
| knives.
|
| I know motor windings have gotten pretty funky of late to
| do a little bit of this, but do they do multi tesla
| magnetic fields that use several different windings to
| create the same sorts of bias in field strength? The ITER
| windings seem to be an extremely mild form of this.
| Alex_001 wrote:
| It's fascinating how NIF's legacy tech limits its relevance
| for actual energy generation, yet it still serves as a
| stepping stone. The fact that gain scales faster than
| linearly with input power is particularly encouraging -- it
| suggests that advances in laser efficiency and repetition
| rate could unlock meaningful progress sooner than many
| assume. I can see why startups are jumping on this now.
| Curious to see how much of this can move from lab to grid in
| the next decade.
| boxed wrote:
| From what I understood, laser fusion needs laser efficiencies
| not just 40x better than what NIF uses, but like 3 or 4
| orders of magnitude more efficient than the state of the art.
| Seems like a non-starter.
| bbatha wrote:
| Everything fusion reactor design needs similar gains in
| some part of the stack outside of the fusion parts to make
| it a viable power source: tokamaks need magnets to be
| orders of magnitude better, the lining for the reactors
| needs to last for much longer, the whole steam conversion
| mess, etc.
| DennisP wrote:
| Commercial REBCO tape is an entirely sufficient
| superconductor for tokamaks. At this point the limiting
| factor for the magnetic field is the structural strength
| of the reactor. Tokamak output scales with the square of
| size and the fourth power of magnetic field strength, and
| using REBCO, the CFS ARC design should get practical
| power output from a reactor much smaller than ITER.
| DennisP wrote:
| NIF's lasers are 0.5% efficient. Equivalent modern lasers
| are 20% efficient. Both of these sources have both numbers:
|
| https://physicsworld.com/a/national-ignition-facilitys-
| ignit...
|
| https://pubs.aip.org/physicstoday/Online/31501/The-
| commercia...
| UltraSane wrote:
| It was never intended to be a power plant but it was hoped that
| it would achieve a net gain fusion reaction for the first time.
| This turned out to be a lot harder than expected.
| hinkley wrote:
| NIF has achieved net power, right? But only if you ignore the
| massive, massive power losses in converting electricity to
| feed energy into the system.
| itishappy wrote:
| Correct. They got more bang out than they put in. The
| electrical-to-bang and bang-to-electrical conversions are
| not included.
| robocat wrote:
| They should also have put fusion bombs on the graph?
| __MatrixMan__ wrote:
| Nothing about the NIF looks like a power plant to me. It's like
| the laser weapons guy and the nuclear weapons guy found a way
| to spend giant piles of money without having to acknowledge the
| weapons angle.
| DennisP wrote:
| A lot of people think so, but the US government openly spends
| _way_ more money on nuclear weapons than on fusion research.
| We 'll spend almost a trillion dollars on nuclear weapons
| over the next decade.[1] The government's fusion funding was
| only $1.4 billion for 2023.[2]
|
| So it seems more likely to me that some physicists figured
| out how to get their fusion power research funded under the
| guise of weapons research, since that's where the money is.
| NIF's original intent was mostly weapons research but it's
| turned out to be really useful for both, and these days,
| various companies are attempting to commercialize the
| technology for power plants.[3]
|
| [1] https://theaviationist.com/2025/04/26/us-nuclear-weapons-
| wil...
|
| [2] https://www.fusionindustryassociation.org/congress-
| provides-...
|
| [3] NYTimes: https://archive.is/BCsf5
| lotharcable wrote:
| Yes. The NIF is a weapons research lab, not a power research
| lab.
|
| The purpose of it is to show that the USA is still capable of
| producing advanced hydrogen bombs. More advanced then anybody
| else.
|
| The '2.05 megajoules' is only a estimation of the laser
| energy actually used to trigger the reaction. It ignores how
| much power it took to actually run the lasers or reactor.
| Even if they update the lasers with modern ones there is zero
| chance of it ever actually breaking even. It is a
| technological dead end as far as power generation goes.
|
| The point of the 'breakthrough' is really more about ensuring
| continued Congressional approval for funding then anything
| else. They are being paid to impress and certainly they
| succeeded in that.
|
| However I suspect this is true of almost all 'fusion
| breakthroughs'. They publish updates to ensure continued
| funding from their respective governments.
|
| People will argue that this is a good thing since it helps
| ensure that scientists continue to be employed and publishing
| research papers. That sentiment is likely true in that it
| does help keep people employed, but if your goal is to have a
| working and economically viable fusion power plant within
| your lifetime it isn't a good way to go about things.
|
| If the governments actually cared about CO2 and man-made
| global warming they would be investing in fusion technology
| and helping to develop ways to recycle nuclear waste
| usefully. Got to walk before you can run.
| hypercube33 wrote:
| It's been over 20 years since ive dug into nuclear tech
| pretty deep but - don't we already have breeder reactors
| and other tech that is low waste, safer and thus we could
| build modern (not based on nuclear submarine) reactors in
| the fission category and deliver cleaner power, today? Yes
| there is a lot of politics especially around manufacturing,
| production and storage of spent fuel so all of those are
| probably show stoppers no matter how safe they are in
| reality but we aren't invested in it.
| crest wrote:
| The primary purpose of the NIF is to maintain the US nuclear
| stockpile without nuclear tests. The lasers very inefficient
| (iirc about 2%). The success they claimed is that the energy
| released by the burning plasma exceeds the laser energy put
| into the fuel capsule. Since NIF was never intended to be a
| power plant they don't use the most efficient lasers.
| trhway wrote:
| ASML machine with "s/tin/DT/" looks like a prototype of such a
| reactor and of a fusion space drive.
| aurizon wrote:
| Yes, after the test ban treaties, there was a huge push into
| exploring mathematical emulations of all aspects of fusion, and
| all assorted bombs, as well as laser ignition of pellets with
| these large lasers using inertial confinement of the pellet as
| the laser impacted it - analysing the fusion by observation of
| emitted neutrons. xrays etc. They issued reports from time to
| time(sanitised), and probably used the secret data to fine tune
| emulated weapons with fact points. The pellets were composed of
| potential fuels, various Hydrogens and Lithiums, varied in
| composition to explore the ignition space. A number of pellets
| performed well in terms of gain, but were far-far from useable
| fusion when the LL labs costs were factored in. I think they
| determined it could not ever work as a fusion energy source,
| but it provided data. They still mine data from it with various
| elemental mixes making up the pellets.
| willis936 wrote:
| There is no need to ask for speculation. It's the top item in
| their mission statement.
|
| https://lasers.llnl.gov/about/what-is-nif
|
| >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.
| numb7rs wrote:
| From my time in fusion research circles, you're correct, but
| it's also not a simple "weapons or energy?" question. It could
| only have ever been a pure research facility. At the time of
| design, the physics wasn't certain enough to aim for net energy
| gain. Where the weapons research came in is in the choice of
| laser focus. Instead of "direct drive", where the lasers
| directly strike the fusion fuel, NIF lasers strike the inside
| of a Hohlraum, which produces X-Rays that then heat the fuel.
| X-Ray opacity is an important topic in nuclear weapons
| research.
|
| Bear in mind that I wasn't directly involved, and this my
| impression picked up from conversations during my time in
| fusion research, which was about 10 years ago.
| UltraSane wrote:
| The money being spent on fusion should be being spent building
| next generation fission power plants and liquid salt reactors.
| sneak wrote:
| What's the ROI on that versus current and near-term expected
| pricing for solar+storage? Is fission getting safer/cheaper at
| the same rate that solar and batteries are?
| UltraSane wrote:
| Solar + days of storage is far more expensive than fission.
| Grid scale batteries like California has spent billions on
| only have 4 hour capacity. Fission can also supply heat that
| is needed for many industrial processes and chemical
| reactions.
| Calwestjobs wrote:
| it is not in most us areas. only problem is area covered,
| NOT price of technology. solar with 12 hour of storage was
| lower price than fission before covid hit. TCO, not one
| time nonsense.
|
| fission has relatively low temperature heat, i.e. no metal
| reduction, no "concrete" production. you can cook hot dogs
| with it. also electrification of heat can provide lower
| losses stemming from regulation or lack thereof. with
| electricity you can say i need 293.5 degrees C and you just
| type it somewhere and you get it for almost free
| (regulation).
| PaulDavisThe1st wrote:
| I am no fan of fission (I strongly oppose new fission
| plants). But one problem with solar+storage is that the
| cost of the storage component increases roughly linearly
| with the desired storage duration. That's not true of a
| fueled power plant (fission or fossil).
| actinium226 wrote:
| Just curious, what makes you oppose new fission plants?
| Do you think existing ones should be closed before their
| scheduled end-of-life?
| worik wrote:
| I will bite.
|
| There are any problems with fission that are all related
| to the extraordinary danger of handling the fuel,
| byproducts, and the sites themselves.
|
| The cost of them is huge, some people are hoping that
| modularity will help with construction, but it is still
| astonishingly expensive.
|
| The problems of handling the fuel has been solved, in
| theory and practise. Except when commerce is involved.
| When the money people get involved corners will get cut,
| and we are back to incredible danger. Technically
| solvable, but I would not go near it. I have known too
| many business people.
|
| The problem of the long-term waste is entirely beyond us.
| There has been no practical progress on this front. Long
| term waste (including some parts of the assemblies
| themselves) are very dangerous for hundreds of thousands
| of years.
|
| This is, with current technology that can be bought to
| bear, unsolvable.
|
| The only thing we can do is put it in a stable site, be
| ready to move it when the site becomes unstable (nowhere
| on Earth is known to be stable on such time scales), and
| find a way of communication, across thousands of
| generations, just how poisonous this stuff is.
|
| Maybe our ancestors will get lucky and find a way to
| safely dispose of it....
|
| So fission power is making future generations pay for
| today's consumption.
|
| Fortunately for us it is moot. The costs of renewables is
| dropped to the point that the only reason for fission is
| to build the capacity for nuclear weapons.
| UltraSane wrote:
| I am so tired of this lie being repeated endlessly. We
| have a perfectly safe way to handle nuclear "waste":
|
| reprocess the dirty fuel and bury the actual waste deep
| underground like Finland is doing at the Onkalo spent
| nuclear fuel repository.
|
| https://en.wikipedia.org/wiki/Onkalo_spent_nuclear_fuel_r
| epo...
|
| And there is still very much a need for zero-carbon
| DISPATCHABLE electricity of witch nuclear is the ONLY
| choice. You simply cannot have 100% of your electricity
| from only solar and wind because it is far too variable
| and we simply don't have the technology to store
| electricity cheaply enough.
|
| Your attitude towards nuclear energy is as irrational as
| the average antivaxer towards vaccines.
| adgjlsfhk1 wrote:
| hydro is also a 0 carbon dispatchable choice (which is
| much cheaper)
| Kubuxu wrote:
| Majority of good spots for hydro were already built up,
| and if they weren't, good luck with NIMBY.
| adgjlsfhk1 wrote:
| meant of the good spots are already used, but we can
| change how they are used to greatly increase their
| usefulness to a 0 carbon grid. we can make them all
| pumped hydro, and start treating hydro as a battery
| rather than a generation source.
| worik wrote:
| > bury the actual waste deep underground
|
| How deep, to stay put thousands of generations?
| UltraSane wrote:
| https://en.wikipedia.org/wiki/Onkalo_spent_nuclear_fuel_r
| epo...
| worik wrote:
| Where are the flow batteries? (fuel cells)
|
| Lithium ion batteries are light with a high energy
| density, so are great for cars.
|
| Flow batteries have a low energy density, but increasing
| the duration means a bigger tank, and the cost of bigger
| tanks increases as a function of the cube root (?) of
| their volume Flow batteries are well over a century old,
| but I have been reading about improvements over the last
| two decades. Where are they?
| ViewTrick1002 wrote:
| Having trouble staying ahead of the enormous monster that
| is the lithium battery industry which through sheer scale
| are lowering the costs allowing it to break into one
| market after another.
|
| It is the good old: Good enough beats theoretically
| perfect.
| Calwestjobs wrote:
| flow batteries are "controlled" by US patents. solar +
| batteries are not limited in bad way by US companies grip
| on patents.
|
| china makes all panels, asia is making all batteries. so
| US utilities / energy providers can not have harmful grip
| on PV + batteries.
|
| US utilities / energy providers want to have docile
| customer who only pays every month. they do not want to
| invest money into grid and have customer not only demand
| but also supply grid. because they do not understand how
| to benefit from that. they can, it is just mental limit
| for them.
|
| utilities / energy providers were too lazy to think about
| proper decentralized grid so every participant in us grid
| will suffer more because of that.
|
| this will be flagged as conspiracy, be cause it is
| conspiracy, conspiracy against US citizen by US companies
| / US interests"
| Calwestjobs wrote:
| this is manipulative
|
| coal power plant needs to have 100 or so rail cars worth
| of material brought every single day. so you are
| simplifying too much.
|
| every person doing anything with power generation should
| put into spreadsheet, what quantities of material is
| needed to provide power capacity for entire grid.
|
| and you need people, infrastructure to bring, prepare,
| load that material. which adds COST OF LOCKING PEOPLE,
| locking workforce for nonsensical jobs. so if someone
| drives train supplying coal plant with coal he can not do
| programming job, job in services etc... labor/workforce
| "opportunity cost"
|
| with PV + battery you bring material once per 10-15
| years. and it is not in quantities as in fossil. and one
| coal plant worth of personnel can manage higher amount of
| generating capacity in PV/battery
|
| Nuclear plant of ANY KIND will have to have even bigger
| workforce than whole coal plant, just to do NONTRIVIAL
| maintenance. just simple microcontroller, sensor.... used
| in nuclear power plant has to be made available for
| duration of plant lifetime 30-40 years. you can use any
| inverter, solar panel in pv, you can interchange them,
| mix them, this is not as simple with nuclear plant.
|
| people involved in providing energy services and citizens
| drawing energy from grid, should start think like
| producers AND consumer, not only like consumers. that way
| a lot of "grid problem" will be easier to deal with.
| aurizon wrote:
| There are a number of flow batteries, where they have large
| vats where charge is stored in 2 discrete charge state
| fluids in a redox reaction. They charge a vat through a
| cell and discharge it in the other direction. Limits are
| solubility of the charge states in the transport fluid =
| huge vats for total watt-hours and huge redox cells for
| rate of charge/discharge. Runs well and vats are cheap.
| https://en.wikipedia.org/wiki/Flow_battery
| greenavocado wrote:
| I wonder if it would make sense to make ultra heavy spent
| nuclear fuel into gigantic flywheels for short-term grid
| energy storage
| myrmidon wrote:
| No. Because flywheels are not limited by material density,
| they are limited by centrifugal force.
|
| High density is actively bad, you want to maximize strength
| and minimize density for flywheel designs, and this makes
| you much more likely to end up with low density composites
| (rather than high density tungsten alloys or somesuch).
| willis936 wrote:
| If you took all the money in the world being spent on fusion
| research right now you would struggle to build a single 1 GWe
| fission power plant. That doesn't sound like an improvement in
| resource allocation to me.
| dale_glass wrote:
| It should be noted that "breakeven" is often misleading.
|
| There's "breakeven" as in "the reaction produces more energy than
| put into it", and there's breakeven as in "the entire reactor
| system produces more energy than put into it", which isn't quite
| the same thing.
| analog31 wrote:
| In the laser business, the latter is called "wall plug
| efficiency," which is laser power out per electrical power in.
| westurner wrote:
| "Uptime Percentage", "Operational Availability" (OA), "Duty
| Cycle"
|
| Availability (reliability engineering)
| https://en.wikipedia.org/wiki/Availability
|
| Terms from other types of work: kilowatt/ _hour_ (kW _h_ ),
| Weight per rep, number of reps, Total Time Under Tension
| kristianp wrote:
| The article uses the term "scientific breakeven" which I assume
| is the first one you've stated.
| gosub100 wrote:
| Especially since steam turbines are in the 30-40% efficiency
| range
| russdill wrote:
| It's always confused me a bit. It's not like if you put 10kWh
| into the reactor, that 10kWh goes away. You still lose a
| significant fraction of it in inefficiency of the cycle but it
| still goes towards heat which can be used to heat steam and
| turn a turbine. iirc, you can get about 4kWh back.
|
| On the other side of the coin, if you put 10kWh in and get
| 10kWh of fusion out, that's 20kWh to run a steam turbine, which
| nets you about 8kWh. So really you need to be producing 15kWh
| of heat from fusion for every 10kWh you put in to break even.
| willis936 wrote:
| Cars are a good analogy. You wouldn't talk about miles per
| gallon until you have an engine that idles. Humans are in the
| engine building phase.
| trollbridge wrote:
| That's a good analogy - and the situation right now is
| trying to make a car that doesn't use its entire tank of
| fuel before it arrives at the service station.
| Tade0 wrote:
| You can't always get this much energy back. Sometimes your
| waste heat is an enormous pool of warm water.
| internet_points wrote:
| and then there's "breakeven" as in "it pays for the investment
| within X years"
| sam wrote:
| We are careful to always specify what kind of "breakeven" or
| "gain" is being referred to on all graphs and statements about
| the performance of specific experiments in this paper.
|
| Energy gain (in the general sense) is the ratio of fusion
| energy released to the incoming heating energy crossing some
| closed boundary.
|
| The right question to ask is then: "what is the closed boundary
| across which the heating energy is being measured?" For
| scientific gain, this boundary is the vacuum vessel wall. For
| facility gain, it is the facility boundary.
| NervousRing wrote:
| I've heard of q-plasma and q-total. What is q-science?
| sam wrote:
| It's the ratio of fusion energy released to heating energy
| crossing the vacuum vessel boundary.
| gene-h wrote:
| This will probably need to be updated soon. There are rumors NIF
| recently achieved a gain of ~4.4 and ~10% fuel burn up. Being
| able to ignite more fuel is notable in and of itself.
| Calwestjobs wrote:
| what "gain" means.
| gene-h wrote:
| Energy out/energy into capsule
| sam wrote:
| In the context implied above it is the ratio of fusion energy
| released to laser energy on target or the laser energy
| crossing the vacuum vessel boundary (they are the same in
| this case). So it would have been more precise to say "target
| gain" or "scientific gain".
| damnitbuilds wrote:
| Hmm. How much of this progress is _really_ progress to actual
| useful fusion power ?
|
| I want to believe, but this does not make that easier.
| stshank wrote:
| Progress toward net fusion energy is critical for delivering
| fusion power on the grid. It's not the only progress required
| -- the rest of the machine has to be economical to build and
| operate. Most of the fusion machines in this paper are
| scientific projects, but as commercialization progresses,
| fusion machines with power plant needs in mind should arrive.
|
| (I work for one startup in the field, Commonwealth Fusion
| Systems. We're building our SPARC tokamak now to demonstrate
| net energy gain in a commercially relevant design.)
| damnitbuilds wrote:
| I wish you luck !
| jamiek88 wrote:
| I'm excited about the new Squids design from the max Planck
| institute, it's a design using the lessons learned from the
| existing stellarator the W7x.
| londons_explore wrote:
| Are there any betting odds on "On-Earth Fusion makes up more than
| 1% of the world energy supply by 2100?"
| sien wrote:
| Metaculus sort of does this. The mean prediction is 2046.
|
| https://www.metaculus.com/questions/9464/nuclear-fusion-powe...
| 0xbadcafebee wrote:
| Amazing! Commercial fusion energy is only 30 years away.
|
| (it's been 30 years away for 50 years already, but as long as I'm
| not dead 30 years from now, it's still a good investment...)
| tim333 wrote:
| Or maybe 10 https://news.mit.edu/2024/commonwealth-fusion-
| systems-unveil...
| deadbabe wrote:
| If you don't need a mobile power plant why bother with fusion
| power instead of something like geothermal? At the end of the day
| we're just turning water into steam.
| Calwestjobs wrote:
| no variant of fusion power is smaller than current coal plant.
| User23 wrote:
| Fusion race vs space race is rather interesting.
| mapt wrote:
| Anyone have any idea where First Light Fusion's third machine
| fits into this?
|
| The idea of using literal guns (gunpowder, then light gas gun,
| then coil gun) to impact projectiles against each other seemed
| like it was probably ludicrous, but I haven't seen any critical
| media or numbers yet.
| chuckleMuscle wrote:
| FLF's own numbers on this are given in a white paper [1, fig
| 7.]. Note the "fusion measured" datapoint used a gas gun,
| rather than Machine-3, as the driver... [1]
| https://firstlightfusion.com/wp-content/uploads/2024/08/firs...
| wonderwonder wrote:
| So much happening in energy right now. If I was to do it again I
| would have focused on this industry.
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