[HN Gopher] Progress toward fusion energy gain as measured again...
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Progress toward fusion energy gain as measured against the Lawson
criteria
Author : sam
Score : 128 points
Date : 2025-05-08 15:49 UTC (7 hours 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?
| 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
| 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
| 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.
| thinkingtoilet wrote:
| I don't see how your comment addresses what I said at all.
| 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.
| 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.
| 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
| 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.
| 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).
| 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
| 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
| 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.
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