5 ms·

> Plenty of other obstacles remain than those noted above, too. Current calculations compare energy generated against the NIF laser’s output, but that brushes o

by rob74 3y ago

> 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 3y ago
>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 3y ago
  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 3y ago
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/ https://ieeexplore.ieee.org/document/650904/ [1]https://royalsocietypublishing.org/doi/10.1098/rsta.2020.0053 https://royalsocietypublishing.org/doi/10.1098/rsta.2020.005...
- megaman821 3y ago
  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 3y ago
    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 3y ago
      $15/MWh is 1.5 ¢/KWh, right? that's pretty darn cheap and means that the other 10~20 cents would be transmission and fuel, yes?
      - repiret 3y ago
        20 cents? I pay 13/kWh.
        Turskarama 3y ago
tonetegeatinst 3y ago
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 3y ago
  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 3y ago
    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 3y ago
      $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.
ess3 3y ago
This basically the plot of the movie ”Real Genius”
- zengid 3y ago
  Great film! https://www.youtube.com/watch?v=xuv7SIVNkx8 https://www.youtube.com/watch?v=xuv7SIVNkx8
  - hyperman1 3y ago
    Oh man. I saw that movie as a kid, and remember thinking the hyperactive girl was really cute. I recently happened to see her scenes again, and unfortunately, the memories were better than the real movie.
DennisP 3y ago
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-energy-start-ups.html https://www.nytimes.com/2023/11/13/science/laser-fusion-ener... [2] https://nap.nationalacademies.org/catalog/18289/an-assessment-of-the-prospects-for-inertial-fusion-energy https://nap.nationalacademies.org/catalog/18289/an-assessmen...
ThrowawayTestr 3y ago
Check out General Fusion who are actually building a scalable fusion reactor.
godelski 3y ago
> 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... I think you answer your own question. NIF does a lot more than weapons. Ignition is also a different problem than sustaining a fusion reaction, but both are important aspects of the fusion energy generation problem. You can think of this like the difference between static friction and kinetic friction. You would never try to generate power by performing tons and tons of ignitions. You generate power by doing the ignition and then sustaining the reaction. There's even people working on setups just like this. You can see how ITER works here[0]. You can modify this procedure to have laser based ignition (or some other form) and then feed this into the toroidal reactor. There's a bunch of ideas out there but I think this is the most straightforward. As to a more systematic approach to answering "why" and why this type of language is pervasive regardless of the domain, is because a lot of people have a difficult time differentiating TRLs[1]. Or maybe even more bluntly, research from products. I think it won't be hard to find high rated HN comments on research works that come out of universities who's critique is that the process is expensive and doesn't beat current industrial processes, but this is a grave misunderstanding of how technological progress happens. It's overly dismissive. Technology often progresses by iterative discontinuous S-curves, which at a zoomed out level looks more smooth. So new technology often starts off way worse but the key part of this is the theoretical maximum. A good example of this might be in batteries or solar panels. People are highly dismissive of any technology that is yet to become a product (TRL 6-7-ish). Which it is good to not jump to assertions that a low TRL result means new products, but it's the same type of error, just in the other direction. Either way, critical context is being ignored. I think if we more appropriately contextualized technological development then we wouldn't have these issues. I don't like them either tbh. I'd rather be honest. But truth has bounded simplicity and lies don't. Since a lot of people ignore nuance it creates an incentive system to exaggerate or leave out important details. Frustrating, but understandable. Hopefully understanding can help us to disrupt this systematic incentive system and instead promote more nuanced and honest discussions. But I think we need to recognize expertise does not transfer between domains well and discourage claims and comments that lack nuance. But nuanced and accurate comments require more words, so we might just be fucked and this is just a pipedream. Some people think we can't rely on humans being nuanced and intelligent creatures but I'm not convinced and more convinced these are just products of environmental pressures. I guess we'll see. [0] https://www.youtube.com/watch?v=5tH4obUsY64 https://www.youtube.com/watch?v=5tH4obUsY64 [1] https://www.nasa.gov/directorates/somd/space-communications-navigation-program/technology-readiness-levels/ https://www.nasa.gov/directorates/somd/space-communications-...

by rob74 3y ago

SigmundA 3y ago

FourHand451 3y ago
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 3y ago

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/ https://ieeexplore.ieee.org/document/650904/ [1]https://royalsocietypublishing.org/doi/10.1098/rsta.2020.0053 https://royalsocietypublishing.org/doi/10.1098/rsta.2020.005...

megaman821 3y ago
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 3y ago
  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 3y ago
    $15/MWh is 1.5 ¢/KWh, right? that's pretty darn cheap and means that the other 10~20 cents would be transmission and fuel, yes?
    - repiret 3y ago
      20 cents? I pay 13/kWh.
      - Turskarama 3y ago

tonetegeatinst 3y ago

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 3y ago
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 3y ago
  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 3y ago
    $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.

ess3 3y ago

This basically the plot of the movie ”Real Genius”

zengid 3y ago
Great film! https://www.youtube.com/watch?v=xuv7SIVNkx8 https://www.youtube.com/watch?v=xuv7SIVNkx8
- hyperman1 3y ago
  Oh man. I saw that movie as a kid, and remember thinking the hyperactive girl was really cute. I recently happened to see her scenes again, and unfortunately, the memories were better than the real movie.

DennisP 3y ago

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-energy-start-ups.html https://www.nytimes.com/2023/11/13/science/laser-fusion-ener... [2] https://nap.nationalacademies.org/catalog/18289/an-assessment-of-the-prospects-for-inertial-fusion-energy https://nap.nationalacademies.org/catalog/18289/an-assessmen...

ThrowawayTestr 3y ago

Check out General Fusion who are actually building a scalable fusion reactor.

godelski 3y ago

> 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... I think you answer your own question. NIF does a lot more than weapons. Ignition is also a different problem than sustaining a fusion reaction, but both are important aspects of the fusion energy generation problem. You can think of this like the difference between static friction and kinetic friction. You would never try to generate power by performing tons and tons of ignitions. You generate power by doing the ignition and then sustaining the reaction. There's even people working on setups just like this. You can see how ITER works here[0]. You can modify this procedure to have laser based ignition (or some other form) and then feed this into the toroidal reactor. There's a bunch of ideas out there but I think this is the most straightforward. As to a more systematic approach to answering "why" and why this type of language is pervasive regardless of the domain, is because a lot of people have a difficult time differentiating TRLs[1]. Or maybe even more bluntly, research from products. I think it won't be hard to find high rated HN comments on research works that come out of universities who's critique is that the process is expensive and doesn't beat current industrial processes, but this is a grave misunderstanding of how technological progress happens. It's overly dismissive. Technology often progresses by iterative discontinuous S-curves, which at a zoomed out level looks more smooth. So new technology often starts off way worse but the key part of this is the theoretical maximum. A good example of this might be in batteries or solar panels. People are highly dismissive of any technology that is yet to become a product (TRL 6-7-ish). Which it is good to not jump to assertions that a low TRL result means new products, but it's the same type of error, just in the other direction. Either way, critical context is being ignored. I think if we more appropriately contextualized technological development then we wouldn't have these issues. I don't like them either tbh. I'd rather be honest. But truth has bounded simplicity and lies don't. Since a lot of people ignore nuance it creates an incentive system to exaggerate or leave out important details. Frustrating, but understandable. Hopefully understanding can help us to disrupt this systematic incentive system and instead promote more nuanced and honest discussions. But I think we need to recognize expertise does not transfer between domains well and discourage claims and comments that lack nuance. But nuanced and accurate comments require more words, so we might just be fucked and this is just a pipedream. Some people think we can't rely on humans being nuanced and intelligent creatures but I'm not convinced and more convinced these are just products of environmental pressures. I guess we'll see. [0] https://www.youtube.com/watch?v=5tH4obUsY64 https://www.youtube.com/watch?v=5tH4obUsY64 [1] https://www.nasa.gov/directorates/somd/space-communications-navigation-program/technology-readiness-levels/ https://www.nasa.gov/directorates/somd/space-communications-...