[HN Gopher] Momentary fusion breakthroughs face hard reality
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Momentary fusion breakthroughs face hard reality
Author : mfiguiere
Score : 88 points
Date : 2024-02-07 06:04 UTC (16 hours ago)
(HTM) web link (spectrum.ieee.org)
(TXT) w3m dump (spectrum.ieee.org)
| twp wrote:
| There's a really good series on what's needed to build a working
| fusion reactor on the YouTube channel "Improbable Matter".
|
| How nuclear fusion works (1) - fusors, thermonuclear reactions,
| lattice fusion: https://www.youtube.com/watch?v=2DzKXN1pcwY
|
| How nuclear fusion works (2) - confinement, stars, nukes,
| inertial fusion energy:
| https://www.youtube.com/watch?v=mxmxZI2Ltvs
|
| How nuclear fusion works (3) - magnetic confinement, tokamaks,
| stellarators: https://www.youtube.com/watch?v=gwOrbr8KWDs
|
| How nuclear fusion (maybe) works (4) - reactor practicalities:
| https://www.youtube.com/watch?v=ZHmHBMaS6Sw
|
| Strongly recommended!
| wolverine876 wrote:
| Who makes "Improbably Matter"?
| rob74 wrote:
| > _Plenty of other obstacles remain than those noted above, too.
| Current calculations compare energy generated against the NIF
| laser's output, but that brushes over the fact that the lasers
| draw more than 100 times the power from the grid than any fusion
| reaction yields. That means either energy gains or laser
| efficiency would need to improve by two orders of magnitude to
| break even in any practical sense. The NIF's fuel pellets are
| also extremely expensive, says Kritcher, each one pricing in at
| an estimated $100,000. Then, producing a reasonable amount of
| power would mean dramatically increasing the frequency of NIF's
| shots -- a feat barely on the horizon for a reactor that requires
| months to load up the next nanosecond-long burst._
|
| "months to load up" is even a euphemism - IIRC they have to
| _repair_ parts of the lasers which are so overpowered that they
| damage their guidance optics with each blast. So the cost for one
| shot is even higher than the $100,000 for the fuel pellet and the
| cost of the energy consumed by the lasers. I wonder why everyone
| skirts around the obvious here: the NIF 's task is _weapons
| research_ , and for that, fusion reactions which last nanoseconds
| might be enough, but there is no way this method can be scaled up
| so it's actually a cost-effective way of producing electricity...
| SigmundA wrote:
| >I wonder why everyone skirts around the obvious here: the
| NIF's task is weapons research, and for that, fusion reactions
| which last nanoseconds might be enough, but there is no way
| this method can be scaled up so it's actually a cost-effective
| way of producing electricity...
|
| We already have fusion weapons that work very well, there is
| some valuable data that can aid weapons design I don't believe
| that to be a primary goal here. Looks like they did shift to
| plutonium targets for a while about a decade ago focusing more
| on weapons research but then shifted back to trying to work
| toward controlled ignition for power generation.
|
| Still a long way to go but the first step is getting more
| energy out then in on the main reaction without using fission
| bombs and destroying the device. Then figure how to scale up to
| get more energy out than in when considering the apparatuses
| efficiency, then getting more out than in when considering heat
| engine efficiency.
| FourHand451 wrote:
| I think you may be slightly misinterpreting the parent
| comment. When they say the NIF's task is weapons research, I
| think they meant that the facility was built with that task
| in mind. When I read your comment it sounds more like you're
| talking about the current task of the people working there.
|
| Both valid points of discussion, but different ones.
| gene-h wrote:
| NIF uses inefficient lasers because they were cheap to build at
| the time and because NIF is a science experiment. Lasers have
| gotten better. And lasers aren't the only way ICF fusion could
| be carried out, it may be possible to use ion beams instead[0].
|
| It does not matter if fusion reactions last microseconds if
| they generate more energy. Using optimistic, but not
| unrealistic assumptions, it appears feasible for electricity
| costs to reach $25 per MWh[1] with ICF. With the most important
| factors driving cost being achieving high gain and yield per
| shot
|
| [0]https://ieeexplore.ieee.org/document/650904/
|
| [1]https://royalsocietypublishing.org/doi/10.1098/rsta.2020.005
| ...
| megaman821 wrote:
| Those numbers don't seem feasible. Near as I can tell, a
| steam generator with a magical source of never-ending heat
| would cost $15/MWh. There is no way a high-tech facility and
| the personnel required to run it are costing $10/MWh.
| notfish wrote:
| What's your math on $15/MWh? As far as I can tell, the
| steam turbine is a pretty insignificant part of the price
| of coal energy generation
| wolfram74 wrote:
| $15/MWh is 1.5 C//KWh, right? that's pretty darn cheap
| and means that the other 10~20 cents would be
| transmission and fuel, yes?
| nimish wrote:
| NIF exists to research nuclear weapons without breaking the
| treaties. Their fusion energy research is a nice corollary
| but it is absolutely not their focus.
| tonetegeatinst wrote:
| I think a lot of people who are really into fusion research
| know that the military isn't going to be doing the same kind of
| fusion research as the groups looking into fusion as an energy
| source.
|
| Is what they did interesting sure, but alot of people who
| actually follow fusion development know that this was a PR meme
| that some news stretched.
|
| Fusion has always been 20 years away its a literal meme....and
| yet we are making good advancements in the field but I think
| anyone with a basic understanding or those who realized this
| was so short lived results time wise realised it was an
| overhyped thing by media from this group.
|
| Fusion is important to the government because they can
| theoretically squeeze more power out of nuclear weapons, but
| due to the difference in timescale zit just dosnt translate
| across domains of military to public energy that well
| JoeAltmaier wrote:
| The US military is very much interested in fusion, as an
| energy source.
|
| The Desert Storm conflict cost something like $1T (yes a
| Trillion dollars) just for gasoline.
|
| There was on this site a description of a military effort to
| create a low-yield fusion generator that would fit on a
| military truck. It only had to fuel a mobile camp, not a
| city. If I recall, it was something like the Lockheed plan,
| to create a vortex (not a torus) to stuff the fuel through a
| constriction and get some kind of fusion yield. Wasteful, but
| not as wasteful as $1T
| LegionMammal978 wrote:
| That seems wildly high? The figure widely quoted for the
| total cost of the Gulf War is $60B in 1991 dollars, or
| $137B today, so clearly the gasoline costs alone can't
| exceed that number. It's only the extremely prolonged
| conflicts like the War in Afghanistan that get into the
| trillions of dollars total.
| ianburrell wrote:
| $1T would be too high for Iraq War where the costs run
| $1T to $3T. The higher numbers are total long-term costs,
| not just the war fighting. There are lots of costs to war
| instead of just fuel; the people cost more.
| JoeAltmaier wrote:
| Yeah way too high.
|
| Here's an estimate of the costs of air conditioning tents
| in the mideast conflicts:
| https://www.npr.org/2011/06/25/137414737/among-the-costs-
| of-...
| vlovich123 wrote:
| Setting aside the wildly suspect 1T claim, I'm not
| convinced by the argument. Fusion power plants are fixed
| large-scale facilities. In a war zone you need mobile power
| sources. I could see a fusion reactor powering a ship and
| maybe powering temporarily shore-based facilities. AFAIK
| the military is looking at solar for mobile power in
| forward deployments though which makes sense. Unless the
| argument is that fusion is used to generate transportable
| fuel (hydrogen, efuels etc). But then that argument is
| weird because the military would be doing that with fission
| today which actually exists and it has to expensive field
| experience with and supply chains supporting.
| indymike wrote:
| > Fusion power plants are fixed large-scale facilities.
|
| Large scale facilities really are not all that
| interesting. They concentrate cost, danger and impose
| lots of logistical limitations.
| JoeAltmaier wrote:
| Consider the Lockheed Skunk Works project - it's supposed
| to be portable.
| wolverine876 wrote:
| I've read that the US military has looked into small
| _fission_ generators. They expect logistics to be very
| difficult near the front if there is a war with a 'near-
| peer' (China or maybe Russia) and hope to reduce fuel
| logistics.
|
| I've never heard of them looking into similar _fusion_
| reactors. Why would they? Nobody expects to build any kind
| of production fusion reactor for decades, much less one
| that could be operated by infantry soldiers and in very
| difficult conditions - e.g., explosions and people shooting
| at the reactor.
| hbossy wrote:
| American military would love to squeeze nuclear reactor
| on every single ship. The conventional escort ships are
| much slower than aircraft carriers and need constant
| refueling, to the point they sometimes leave them behind
| and sail meet another fleet in destination port. It's not
| really feasible with fission but fusion would make it a
| lot safer.
| AlbertCory wrote:
| > a low-yield fusion generator that would fit on a military
| truck.
|
| another word for that is "drone target."
| JoeAltmaier wrote:
| Everything in war is a target
| AlbertCory wrote:
| True, but a small target that disables all the
| electronics on the base would have to be considered "high
| value."
| wolverine876 wrote:
| > a lot of people who are really into fusion research
|
| Do you mean researchers and other experts, or people who
| follow it? And does that include you? Are you a researcher?
| ess3 wrote:
| This basically the plot of the movie "Real Genius"
| zengid wrote:
| Great film! https://www.youtube.com/watch?v=xuv7SIVNkx8
| DennisP wrote:
| Efficiency of equivalent lasers has improved by about 40X since
| NIF was built, and they seem to have nonlinear scaling on
| fusion output. NIF definitely isn't a practical energy system,
| but it is an experiment that helps move us in that direction.
|
| Here's a NYTimes article[1] about various companies attempting
| laser fusion for power production. One of them has an approach
| very similar to NIF's, and a couple others are similar but do
| away with the need for a hohlraum by using a different type of
| laser. They also say:
|
| "A decade ago, a report[2] by the National Academy of Sciences
| found much to like in the energy potential of laser fusion but
| recommended that the United States hold off major investments
| until ignition was achieved. That time is now."
|
| [1] https://www.nytimes.com/2023/11/13/science/laser-fusion-
| ener...
|
| [2] https://nap.nationalacademies.org/catalog/18289/an-
| assessmen...
| ThrowawayTestr wrote:
| Check out General Fusion who are actually building a scalable
| fusion reactor.
| 1970-01-01 wrote:
| ..using the laser approach. Other approaches don't have that
| issue:
|
| https://www.iaea.org/newscenter/news/tokamaks-stellarators-l...
| rob74 wrote:
| I guess that's why they're using "Momentary Fusion" in the
| title? Of course, it wouldn't have hurt to mention in the
| article that other approaches which _might_ be more feasible
| also exist...
| zug_zug wrote:
| Well those of us who have never heard of "momentary fusion"
| read the title to mean "momentary breakthroughs in fusion"
| Manabu-eo wrote:
| I never heard the term "Momentary Fusion". There are other
| pulsed fusion methods, like Dense Plasma Focus[1] with it's
| very hot but very short lived plasmoids. Also still far from
| being economically viable, but I would say has a much better
| chance than that weapon research on NIF[2].
|
| [1] https://en.wikipedia.org/wiki/Dense_plasma_focus
|
| [2] https://spectrum.ieee.org/startup-lppfusion-embraces-
| instabi...
| dukoid wrote:
| My bets are on Wendelstein 7-X / Stellarators
| gene-h wrote:
| The work from Rochester mentioned briefly is probably the second
| best performing fusion experiment and this was done with a laser
| that's at least 29 years old.
|
| What the article doesn't mention is that the approach
| demonstrated could decrease the cost of fuel pellets. In NIF, the
| laser energy is converted to X-rays which compress the fuel
| pellet using expensive elements like gold. What they demonstrated
| is that the fuel pellet can be imploded directly with the lasers.
| _a_a_a_ wrote:
| OT but are there any links to resources about using
| fission/fusion bombs directly for energy production?
| philipkglass wrote:
| The concept was explored in the United States as Project PACER:
|
| https://en.wikipedia.org/wiki/Project_PACER
| _a_a_a_ wrote:
| excellent, thanks
| wolverine876 wrote:
| Why go through the expense of engineering and manufacturing a
| bomb, and then use it for a different purpose? If you want an
| electricity generator, engineer and manufacture for that. Or
| are you thinking of using excess bombs?
|
| I want to say that fusion bombs require more energy input than
| they output, because until recently nobody has been able to
| create fusion reactions otherwise (and now only in a very
| limited way). But is that true? Fusion bombs release an
| incredible amount of energy. Maybe it's that they release it
| all at once, but still, how does that equation work out?
| _a_a_a_ wrote:
| > Why go through the expense of...
|
| Good question. I should have asked strictly about fusion
| bombs. These being a known-working example of energy
| production by fusion, why not use them when we can't get
| 'controlled' fusion working?
| thmsths wrote:
| From my recollection, even in a fusion bomb, most of the
| energy comes from the fission. I don't fully
| remember/understand the physics involved. But apparently
| the fission reaction triggers the fusion reaction (that
| part I get) and then that fusion reaction in turns boosts
| the fission reaction.
|
| So my takeaway is that fission bombs are not very efficient
| to begin with. You're after all trying to extract as much
| energy as possible as quickly as possible from a system
| that is literally self destructing. We do not have that
| constraint with current fission plants, the plant is
| designed to run in a steady state for years, the fissile
| materials stay in place and my intuition is that this
| significantly helps efficiency.
| apendleton wrote:
| Yes, the gist is that in a fusion device, you've got a
| chain reaction where the splitting uranium or plutonium
| is making neutrons, and those neutrons strike other
| uranium or plutonium, which makes more neutrons, etc. But
| you have a very short period of time to take advantage of
| this chain reaction, because before long, your device has
| blown apart, so a large percentage of the fuel in a
| conventional fission device never undergoes fission (the
| device has blown up before it has a chance). The job of
| the fusion reaction in a fission-fusion-fission device
| (how "modern" thermonuclear weapons work) is, in addition
| to producing energy of its own, to rapidly produce lots
| of lots of neutrons, which can very quickly fission a
| second quantity of fissile material.
| throwaway44023 wrote:
| One of the biggest challenges is that the fusion reaction
| can't be fully contained. There are particles without
| electric charge that simply go through your magnetic
| containment field and smash into the reactor wall,
| continuously destroying it. You don't really care about
| preserving the shell of your bomb. You care about
| preserving the shell of your reactor.
| wolverine876 wrote:
| How do fusion researchers handle that problem?
| philipkglass wrote:
| Let me elaborate on thmsths's answer. The United States
| developed and tested large "clean" fusion bombs that
| produced only a very small fraction of their energy from
| fission. Those bombs could produce raw thermal energy at a
| cost below any fossil fuel or conventional nuclear reactor.
| For example, the Housatonic test shot of Operation Dominic
| in 1962 yielded about 10 megatons and 99.9% of the energy
| released came from fusion [1].
|
| The problem is that explosions of that magnitude are not
| usable for controlled energy generation. Confining them
| underground is impractical, due to the scale of energy
| release. The largest underground US test was 5 megatons in
| 1971, and it was so disruptive (induced surface motion
| equivalent to an earthquake) that it had to be conducted at
| a remote Alaskan island instead of the usual Nevada test
| site [2].
|
| For those reasons, Project PACER considered bombs of only
| up to 50 kilotons. At those sizes (0.5% the energy yield of
| Housatonic), there is no known design to get 90%+ of the
| bomb's energy yield from fusion. The efficient fusion
| designs don't gracefully scale down to that range. And at
| that much smaller scale where underground confinement was
| practical, bombs were not actually any cheaper as a source
| of raw thermal energy. Quoting Wikipedia about the project
| here, "In a 1975 review of the various Plowshares efforts,
| the Gulf University Research Consortium (GURC) considered
| the economics of the PACER concept. They demonstrated that
| the cost of the nuclear explosives would be the equivalent
| of fuelling a conventional light-water reactor with uranium
| fuel at a price of $328 per pound. Prices for yellowcake at
| that point were $27 a pound."
|
| [1] "Ripple: An Investigation of the World's Most Advanced
| High-Yield Thermonuclear Weapon Design"
| http://web.mit.edu/zoz/Public/jcws_a_01011.pdf
|
| [2] https://en.wikipedia.org/wiki/Cannikin
| gentleman11 wrote:
| Imagine a second Manhattan Project, except this time, it's to
| produce fusion energy and try to save the world from climate
| disasters instead of making a weapon.
|
| Who would you tap to participate in/lead this?
| throwaway44023 wrote:
| Elon Musk and his ability to gather financing and top engineers
| astrange wrote:
| Better get him to rehab first.
| killingtime74 wrote:
| Oppenheimer again
| Karellen wrote:
| Why do you think finishing the fusion research (just another 10
| years? again?), and then designing commercial reactors, and
| then building out all the fusion generation capacity we need,
| could possibly take less time/money/effort than just building
| out all the wind/solar/battery capacity instead, which we
| already know how to make?
| thrance wrote:
| We already have the ITER project, a well-funded international
| (~35 nations) attempt at building a fusion reactor prototype.
|
| Also we probably shouldn't count on a miracle to save us from
| climate change.
| AtlasBarfed wrote:
| I don't think fusion will ever be cheaper than solar and wind
| KiwiJohnno wrote:
| No, but it will be more reliable, and potentially portable.
| Both very important characteristics.
|
| I do agree that distributed solar and wind (with battery
| storage) can take take care of grid base load, but that doesn't
| mean fusion is pointless.
| gregfjohnson wrote:
| A new fusion company name Blue Laser Fusion is working on
| inertial fusion with new laser technology. Does anyone have
| information on what they are doing, and what the prognosis is for
| that company's approach?
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