10 ms·

It is an important milestone. But to have a commercially viable fusion reactor, you'll need a factor of 50-100 more energy out than in to make up for inefficien

by sam 13y ago

It is an important milestone. But to have a commercially viable fusion reactor, you'll need a factor of 50-100 more energy out than in to make up for inefficiencies in electricity generation using this kind of scheme. The real story here is that this facility allows the US to do nuclear weapons research without violating the nuclear test ban treaty. If the goal was to develop a commercially viable fusion reactor, the $3,500,000,000 spent so far could have been put into projects geared towards small scale fusion experiments investigating novel confinement schemes. Like the one I was working on, http://meetings.aps.org/Meeting/DPP07/Event/71002 http://meetings.aps.org/Meeting/DPP07/Event/71002 whose funding has since been cut and has been mothballed.

pjlegato 13y ago
Speculating about their "real" motives is just that; speculation. I'm sorry your project was defunded, but that in itself is not evidence that the facility is actually a sham.
- skorgu 13y ago
  NIF is explicitly and publicly a weapons research facility; it's right there on their website[0]. If they happen to do some useful scientific or commercial work then yay but it's a nice byproduct. [0] https://lasers.llnl.gov/about/missions/ https://lasers.llnl.gov/about/missions/
  - pjlegato 13y ago
    Actually, the site you linked lists 3 goals. Weapons research is only one of them. The other two are commercial and scientific research. Those are not mere byproducts, but explicit goals of the facility.
    - jacquesm 13y ago
      They're fig leaves.
- darkmighty 13y ago
  He's not saying the facility is a sham, he is simply saying it's goals are not to generate electricity, it's simply a research tool to provide data to improve empirical models. Those models of course have all sorts of uses, and certainly a big one is nuclear weapon modelling.
- njharman 13y ago
  You say "speculation" as if it were a bad thing.
  - pjlegato 13y ago
    I could speculate that space aliens secretly landed in Roswell and took over the government 60 years ago, but without evidence, it's just a story.
volokoumphetico 13y ago
So sorry to hear that project got cut from spending. It really seems like another extremely powerful nuclear bomb.
acadien 13y ago
Finally someone that's actually in the fusion field. Could you say whether or not the NIF research represents a practical path towards a fusion based power source? My understanding is that it would at least be capable of capturing some much needed high pressure empirical data necessary for validating theory. On a side note concerning the NIF funding, the US gov will spend huge sums of money studying Nuclear weapons (including their disposal) regardless of the NIF project. If it is at all possible to combine that research with other fields then really it's a perk. I'm not justifying the expenditure, simply attempting to frame the situation in a different light. Finally, as a fellow scientist with funding woes, I feel your pain.
- mrterry 13y ago
  I've worked in ICF for a nearly a decade. I think NIF research is a necessary step to a ICF based power source. If NIF demonstrates ignition, it can be used to validate our physics models of ICF (turbulence, fusion product transport, thermal conduction, etc). These physics questions are shared by all ICF approaches. However, a fusion power plant will use entirely different laser technology [1], and most likely a different target design [2]. After showing that the physics works, there is still a lot of engineering work needed before building a reactor. [1] An ICF power plant will be pulsed at 1-10 Hz. NIF is a flash-lamp pumped glass laser, which takes ~12 hours to cool between shots. A power plant would likely be diode-pumped sold state laser since these can meet the required repitition-rate. [2] The indirect drive target that LLNL is pursuing on NIF is not very efficient. You spend a lot of energy heating the hohlraum. Directly driven targets (blast the capsule directly rather than heating a gold can to make x-rays) should be much more efficient. There are also several ideas for ways to ignite a target more efficiently (shock ignition, fast ignition), but these need additional laser hardware. @sam Though I work in ICF, I was sad to see the innovative confinement concepts (magnetic confinement) cut a couple years ago. I think it is short sighted. Fusion need to work and get smaller and we should keep our options open. Hope you managed to get a thesis out before the walls fell.
  - acadien 13y ago
    I thought the goal was to have a self sustaining reaction that would only require laser pulses to hold it in place. Is a continuously pulsed laser necessary to provide thermal energy to drive the reaction? Also I've read (sorry no citation) that the indirect drive was necessary to ensure even dispersal of the heat generated by the initiating laser blast. Any clarification would be much appreciated, this isn't my field.
viraj_shah 13y ago
"Lawrence Livermore National Laboratory has a mission of strengthening the United States’ security through development and application of world-class science and technology to: Enhance the nation’s defense; Reduce the global threat from terrorism and weapons of mass destruction; And respond with vision, quality, integrity and technical excellence to scientific issues of national importance." https://www.llnl.gov/about/whatwedo.html https://www.llnl.gov/about/whatwedo.html
cyanoacry 13y ago
This is definitely true, and the BBC totally omitted these facts. The official NIF announcement[1] tried a little bit to cover their tracks. They posted some flashy numbers about the total energy output from neutrons, but nestled in the bottom of the page is the total energy dumped into the entire system: 1.7 megajoules. In comparison, the fusion power produced was a paltry 8 kilojoules, which they compare to the "energy required to form the plasma". For this technology to be actually effective, there needs to be a multiplier of several thousand. As other commenters have mentioned, this is mostly just nuclear weapons development. [1] http://www.physicstoday.org/daily_edition/politics_and_policy/lab_reports_big_advance_in_laser_fusion_quest?type=PTFAVE http://www.physicstoday.org/daily_edition/politics_and_polic...
- NegativeK 13y ago
  The BBC did say: > the amount of energy released through the fusion reaction exceeded the amount of energy being absorbed by the fuel As soon as I saw that, I immediately understood that they're nowhere near breakeven -- much less power generation.
  - ballard 13y ago
    It's an extremely misleading half-truth. Worse, Q must be an order of magnitude greater than 1 IIRC to be economically viable.
    - drjesusphd 13y ago
      They did not mention Q at all in the article and their claims cannot be compared to any intellectually honest definition of "break even" in good faith without more information
      - ballard 13y ago
        IIRC from a recent HN discussion, ITER has attained Q of 0.65 and NIF is nowhere close to that.
TylerE 13y ago
If we could get a fusion design that works a bit over unity, couldn't you, well, chain them? E.g. 1MW basic plant that drives a 1.5MW plant that drives a 2.25MW -> 4 -> 6 -> 9 etc, however many stages you need.
- ars 13y ago
  Yes, but you have to pay for the power plant, and being just a bit over unity won't cover the expense of the next stage in the chain. You have to be enough over unity to pay for another plant plus surplus to actually use. In which case you can just build a bunch of plants - you don't need to chain them. There are plenty of other power sources you can use to bootstart the power plants. Even regular power plants need power to start them see https://en.wikipedia.org/wiki/Black_start https://en.wikipedia.org/wiki/Black_start
mrterry 13y ago
"50-100 more energy out than in to make up for inefficiencies in electricity generation using this kind of scheme." Completely true. Theoretically, the NIF target has enough fuel to produce 10-20x the amount of laser energy driving it. Once things work, it isn't a huge step to get to an energy gain (energy_out/energy_in) of ~50. That said, the real world is always more complicated and NIF has yet to ignite.
MichaelMoser123 13y ago
I am waiting for the hack of cold fusion; Now wikipedia says that imploding bubbles create some high energies; http://en.wikipedia.org/wiki/Mechanism_of_sonoluminescence http://en.wikipedia.org/wiki/Mechanism_of_sonoluminescence http://en.wikipedia.org/wiki/Bubble_fusion http://en.wikipedia.org/wiki/Bubble_fusion Maybe if you shoot up Deuterium bubbles in compressed water and push in some ultrasound waves ....
tsenkov 13y ago
I wonder, what more do they need in nuclear weapons? Smaller size? Harder detection? Bigger contamination radius? Somehow, I am sure, if people start a nuclear war, even the WWII's initial nuclear weaponry will be enough to destroy ourselves, knowing how many countries can now chime in with their own.
- XorNot 13y ago
  Cover the bases: you can't be sure someone else won't discover a new type of nuclear weapon or something you haven't thought of. The big one would be if someone figured out how to get kiloton->megaton yields, from a weapon which didn't produce radioactive fallout. Sure, target a city and it's functionally indistinguishable, but what about against military formations or bunkers? It would be a big game changer if someone eliminated the fallout problem, since it changes how one could plan to use nukes in a defensive posture. So you do the research to make sure you're always within a year or two of whatever the next state-of-the-art will be. Being the dominant hegemon has a lot of cost-of-living expenses.
- deleted 13y ago
  [deleted]
- JonnieCache 13y ago
  The US now has a notion of "tactical" nuclear weapons. Some reading: http://www.fas.org/_docs/Non_Strategic_Nuclear_Weapons.pdf http://www.fas.org/_docs/Non_Strategic_Nuclear_Weapons.pdf God help us all.
  - ewoodrich 13y ago
    That's been around since 1953 (less than a decade after the first atomic detonation in '45). [1] And we've maintained a limited number of low-yield warheads that would fall under that designation. [2] (as an example) [1] http://en.wikipedia.org/wiki/Nuclear_artillery http://en.wikipedia.org/wiki/Nuclear_artillery [2] http://en.wikipedia.org/wiki/B61_nuclear_bomb http://en.wikipedia.org/wiki/B61_nuclear_bomb
- VLM 13y ago

by sam 13y ago

pjlegato 13y ago

Speculating about their "real" motives is just that; speculation. I'm sorry your project was defunded, but that in itself is not evidence that the facility is actually a sham.

skorgu 13y ago
NIF is explicitly and publicly a weapons research facility; it's right there on their website[0]. If they happen to do some useful scientific or commercial work then yay but it's a nice byproduct. [0] https://lasers.llnl.gov/about/missions/ https://lasers.llnl.gov/about/missions/
- pjlegato 13y ago
  Actually, the site you linked lists 3 goals. Weapons research is only one of them. The other two are commercial and scientific research. Those are not mere byproducts, but explicit goals of the facility.
  - jacquesm 13y ago
    They're fig leaves.
darkmighty 13y ago
He's not saying the facility is a sham, he is simply saying it's goals are not to generate electricity, it's simply a research tool to provide data to improve empirical models. Those models of course have all sorts of uses, and certainly a big one is nuclear weapon modelling.
njharman 13y ago
You say "speculation" as if it were a bad thing.
- pjlegato 13y ago
  I could speculate that space aliens secretly landed in Roswell and took over the government 60 years ago, but without evidence, it's just a story.

volokoumphetico 13y ago

So sorry to hear that project got cut from spending. It really seems like another extremely powerful nuclear bomb.

acadien 13y ago

Finally someone that's actually in the fusion field. Could you say whether or not the NIF research represents a practical path towards a fusion based power source? My understanding is that it would at least be capable of capturing some much needed high pressure empirical data necessary for validating theory. On a side note concerning the NIF funding, the US gov will spend huge sums of money studying Nuclear weapons (including their disposal) regardless of the NIF project. If it is at all possible to combine that research with other fields then really it's a perk. I'm not justifying the expenditure, simply attempting to frame the situation in a different light. Finally, as a fellow scientist with funding woes, I feel your pain.

mrterry 13y ago
I've worked in ICF for a nearly a decade. I think NIF research is a necessary step to a ICF based power source. If NIF demonstrates ignition, it can be used to validate our physics models of ICF (turbulence, fusion product transport, thermal conduction, etc). These physics questions are shared by all ICF approaches. However, a fusion power plant will use entirely different laser technology [1], and most likely a different target design [2]. After showing that the physics works, there is still a lot of engineering work needed before building a reactor. [1] An ICF power plant will be pulsed at 1-10 Hz. NIF is a flash-lamp pumped glass laser, which takes ~12 hours to cool between shots. A power plant would likely be diode-pumped sold state laser since these can meet the required repitition-rate. [2] The indirect drive target that LLNL is pursuing on NIF is not very efficient. You spend a lot of energy heating the hohlraum. Directly driven targets (blast the capsule directly rather than heating a gold can to make x-rays) should be much more efficient. There are also several ideas for ways to ignite a target more efficiently (shock ignition, fast ignition), but these need additional laser hardware. @sam Though I work in ICF, I was sad to see the innovative confinement concepts (magnetic confinement) cut a couple years ago. I think it is short sighted. Fusion need to work and get smaller and we should keep our options open. Hope you managed to get a thesis out before the walls fell.
- acadien 13y ago
  I thought the goal was to have a self sustaining reaction that would only require laser pulses to hold it in place. Is a continuously pulsed laser necessary to provide thermal energy to drive the reaction? Also I've read (sorry no citation) that the indirect drive was necessary to ensure even dispersal of the heat generated by the initiating laser blast. Any clarification would be much appreciated, this isn't my field.

viraj_shah 13y ago

"Lawrence Livermore National Laboratory has a mission of strengthening the United States’ security through development and application of world-class science and technology to: Enhance the nation’s defense; Reduce the global threat from terrorism and weapons of mass destruction; And respond with vision, quality, integrity and technical excellence to scientific issues of national importance." https://www.llnl.gov/about/whatwedo.html https://www.llnl.gov/about/whatwedo.html

cyanoacry 13y ago

This is definitely true, and the BBC totally omitted these facts. The official NIF announcement[1] tried a little bit to cover their tracks. They posted some flashy numbers about the total energy output from neutrons, but nestled in the bottom of the page is the total energy dumped into the entire system: 1.7 megajoules. In comparison, the fusion power produced was a paltry 8 kilojoules, which they compare to the "energy required to form the plasma". For this technology to be actually effective, there needs to be a multiplier of several thousand. As other commenters have mentioned, this is mostly just nuclear weapons development. [1] http://www.physicstoday.org/daily_edition/politics_and_policy/lab_reports_big_advance_in_laser_fusion_quest?type=PTFAVE http://www.physicstoday.org/daily_edition/politics_and_polic...

NegativeK 13y ago
The BBC did say: > the amount of energy released through the fusion reaction exceeded the amount of energy being absorbed by the fuel As soon as I saw that, I immediately understood that they're nowhere near breakeven -- much less power generation.
- ballard 13y ago
  It's an extremely misleading half-truth. Worse, Q must be an order of magnitude greater than 1 IIRC to be economically viable.
  - drjesusphd 13y ago
    They did not mention Q at all in the article and their claims cannot be compared to any intellectually honest definition of "break even" in good faith without more information
    - ballard 13y ago
      IIRC from a recent HN discussion, ITER has attained Q of 0.65 and NIF is nowhere close to that.

TylerE 13y ago

If we could get a fusion design that works a bit over unity, couldn't you, well, chain them? E.g. 1MW basic plant that drives a 1.5MW plant that drives a 2.25MW -> 4 -> 6 -> 9 etc, however many stages you need.

ars 13y ago
Yes, but you have to pay for the power plant, and being just a bit over unity won't cover the expense of the next stage in the chain. You have to be enough over unity to pay for another plant plus surplus to actually use. In which case you can just build a bunch of plants - you don't need to chain them. There are plenty of other power sources you can use to bootstart the power plants. Even regular power plants need power to start them see https://en.wikipedia.org/wiki/Black_start https://en.wikipedia.org/wiki/Black_start

mrterry 13y ago

"50-100 more energy out than in to make up for inefficiencies in electricity generation using this kind of scheme." Completely true. Theoretically, the NIF target has enough fuel to produce 10-20x the amount of laser energy driving it. Once things work, it isn't a huge step to get to an energy gain (energy_out/energy_in) of ~50. That said, the real world is always more complicated and NIF has yet to ignite.

MichaelMoser123 13y ago

I am waiting for the hack of cold fusion; Now wikipedia says that imploding bubbles create some high energies; http://en.wikipedia.org/wiki/Mechanism_of_sonoluminescence http://en.wikipedia.org/wiki/Mechanism_of_sonoluminescence http://en.wikipedia.org/wiki/Bubble_fusion http://en.wikipedia.org/wiki/Bubble_fusion Maybe if you shoot up Deuterium bubbles in compressed water and push in some ultrasound waves ....

tsenkov 13y ago

I wonder, what more do they need in nuclear weapons? Smaller size? Harder detection? Bigger contamination radius? Somehow, I am sure, if people start a nuclear war, even the WWII's initial nuclear weaponry will be enough to destroy ourselves, knowing how many countries can now chime in with their own.

XorNot 13y ago
Cover the bases: you can't be sure someone else won't discover a new type of nuclear weapon or something you haven't thought of. The big one would be if someone figured out how to get kiloton->megaton yields, from a weapon which didn't produce radioactive fallout. Sure, target a city and it's functionally indistinguishable, but what about against military formations or bunkers? It would be a big game changer if someone eliminated the fallout problem, since it changes how one could plan to use nukes in a defensive posture. So you do the research to make sure you're always within a year or two of whatever the next state-of-the-art will be. Being the dominant hegemon has a lot of cost-of-living expenses.
deleted 13y ago
[deleted]
JonnieCache 13y ago
The US now has a notion of "tactical" nuclear weapons. Some reading: http://www.fas.org/_docs/Non_Strategic_Nuclear_Weapons.pdf http://www.fas.org/_docs/Non_Strategic_Nuclear_Weapons.pdf God help us all.
- ewoodrich 13y ago
  That's been around since 1953 (less than a decade after the first atomic detonation in '45). [1] And we've maintained a limited number of low-yield warheads that would fall under that designation. [2] (as an example) [1] http://en.wikipedia.org/wiki/Nuclear_artillery http://en.wikipedia.org/wiki/Nuclear_artillery [2] http://en.wikipedia.org/wiki/B61_nuclear_bomb http://en.wikipedia.org/wiki/B61_nuclear_bomb
VLM 13y ago