7 ms·

Is this "plasma breakeven" or overall break-even?

akeck 5y ago
Probably just "plasma breakeven" Sabine talks about the issue. [1] https://backreaction.blogspot.com/2021/10/how-close-is-nuclear-fusion-power.html https://backreaction.blogspot.com/2021/10/how-close-is-nucle...
- mlindner 5y ago
  Sabine actually is completely misleading and misconstrues a bunch of facts. None of these plants are even attempting to have real energy breakeven and spend a ton of energy supplying experiments and unrelated support equipment. They don't even have a method of capturing energy as that's not the point as it would make it harder to test the physics. Additionally these plants have high amounts of "startup energy consumption" that is also factored in to the energy usage but would be amortized out over a long run. Trying to use the absolute power consumption of the experiment as if that's where the state of the art is at for true energy break even is completely wrong. Plasma breakeven is all anyone is really working on. Once you have plasma breakeven you have a self-sustaining heater basically, which then can be used to create energy. The point of an "ignited plasma" is that it's self-sustaining and just pumps out heat, even if most of the energy is used to keep the reaction going.
  - tootie 5y ago
    I think her meaning is pretty clear and correct. As much as plasma breakeven may be the entire goal of ITER it's absolutely setting them up for a badly missed public expectation. The day they declare net positive output, the world will ask when we can start building infrastructure and the answer will be "30 more years" and then they'll get their funding yanked forever.
    - mlindner 5y ago
      ITER isn't even possible to create an economic nuclear reactor out of because it's too big. The sheer size of a ITER-sized reactor doesn't get us to economical reactors. ITER is a science experiment, not a commercial reactor design. High-field strength high temperature superconductor based allows much smaller sizes than ITER, but ITER was designed with the technology that was available in the late 1990s.
    - willis936 5y ago
      >As much as plasma breakeven may be the entire goal of ITER Who gave you that impression? They were lying. The goal of ITER has always been to study burning plasmas and experiment with solutions to problems that a reactor-grade MCF machine faces.
  - ckuehne 5y ago
    I think your statement "Once you have plasma breakeven you have a self-sustaining heater basically" is false. According to Wikipedia [1] - if I interpret it correctly - the fusion energy gain factor from plasma must be 5 (!) to have a self-sustaining heater: "Most fusion reactions release at least some of their energy in a form that cannot be captured within the plasma, so a system at Q = 1 will cool without external heating. With typical fuels, self-heating in fusion reactors is not expected to match the external sources until at least Q = 5" [1] https://en.wikipedia.org/wiki/Fusion_energy_gain_factor https://en.wikipedia.org/wiki/Fusion_energy_gain_factor
    - mlindner 5y ago
      I oversimplified in that statement, you need more than a factor of 1 because of heat losses to the environment yes. However 5 is not much different than 1. We've gone from 0.0001 only a few years ago to close to 1 now. And btw, you really want more than 5, 10 or 20 ideally, but again, that's not too hard as compared to how far we've come and new reactors will be beyond that soon.
    - willis936 5y ago
      Fusion begets fusion. ITER plans to have high-intensity, relatively short Q=10 shots. If the plasma heats itself then it doesn't need much heating. This sudden focus on Q is clearly the result of one vocal non-expert not understanding the field and everyone listening to them like they have something valuable to teach.
  - tsimionescu 5y ago
    > Plasma breakeven is all anyone is really working on. Once you have plasma breakeven you have a self-sustaining heater basically, which then can be used to create energy. The point of an "ignited plasma" is that it's self-sustaining and just pumps out heat, even if most of the energy is used to keep the reaction going. This is dead wrong. First of all, the experiment described here is ICF, in which you have to constantly re-heat new pellets of fuel. Even for MCF, you have to spend inordinate amounts of energy just containing the million kelvins plasma with few kelvin superconducting magnets, and to constantly deliver new D+T into the plasma. If containment fails at any time for any amount of time, your reactor is instantly obliterated. Not to mention, your source of heat only heats up by about half of the energy - the other half is radiated away as hard to capture neutrons, which are almost entirely a waste product. I have no idea why you think that ignited plasma is enough to maintain an energy-producing reactor. Edit: million kelvins should have been billion kelvins...
    - jhgb 5y ago
      > the other half is radiated away as hard to capture neutrons, which are almost entirely a waste product I thought the neutrons were supposed to take away the heat, to be absorbed in layers of water?
      - tsimionescu 5y ago
        Reading more about this, it seems that one of the ideas is indeed to capture the neutrons in a liquid lithium blanket, that would then produce both heat and tritium, and using that heat, that is outside the magnetic confinement, to connect to a turbine. Unfortunately, I believe that the area of actually capturing the energy of the fusion reaction is almost entirely unstudied yet in practice.
jacquesm 5y ago
From TFA: "The pace of improvement in energy output has been rapid, suggesting we may soon reach more energy milestones, such as exceeding the energy input from the lasers used to kick-start the process."
- birdman3131 5y ago
  These people grew up on Wow and are familiar with Soon™.
  - deleted 5y ago
    [deleted]
Cerium 5y ago
I think it is neither. Most nuclear fusion news is focused on magnetic confinement. This article is about reaching ignition on an inertial confinement system.
lisper 5y ago
Neither. From TFA: "While the latest experiment still required more energy in than it got out, it is the first suspected to reach the crucial stage of ‘ignition’, which allowed considerably more energy to be produced than ever before, and paves the way for ‘break even’, where the energy in is matched by the energy out." Here [1] is an excellent video by Sabine Hossenfelder about why you should not get too excited about this result. [1] https://www.youtube.com/watch?v=LJ4W1g-6JiY https://www.youtube.com/watch?v=LJ4W1g-6JiY
- mlindner 5y ago
  It's neither, agreed. However, Sabine misconstrues things in the opposite direction and lies through omission to the audience. For example including startup energy and not ammortizing it over runtime, or not assuming that the energy consumption of the experiments is part of the required energy consumption of the fusion reactor, or trying to construe that once you have a fusion power reaction that is burning it is still especially difficult to further create a functioning power reactor out of it. The true hard part of fusion is the burning plasma aspect. Once you have a burning plasma, it's a heat source like any other (with a few side-effects like neutron output) and everything we know from fission power reactors (but with a much lower radiation) and fossil fuel generators applies.
  - dcow 5y ago
    Where are you getting this impression? Her video pretty clearly focuses on the confusion between the Qs. Where does she get the napkin math wrong? She uses a published figure for total energy required during the operation of ITER when it’s up and running not a one time startup cost figure. Id she misrepresented that number, what would be a more honest total power consumption figure? As far as construing the output, she uses existing loss ratio for heat to electrical energy conversion which really does not seem to work to construe the problem as “especially difficult”, it’s “normally difficult” is how I interpreted. Are there impending advancements in energy conversion that makes 50% too liberal?
    - mlindner 5y ago
gene-h 5y ago
What's important here is that they may have achieved ignition, that is making the fusion reaction self sustaining[0]. Once it becomes self sustaining one should be able to add more fuel to the pellet to get more energy out for the same input energy. It's worth noting that NIF was not intended to generate power and is not representative of a potential power plant. The lasers on NIF are old and were chosen to have a lower efficiency for cost reasons. In addition, while NIF could generate much more energy, NIF isn't necessarily going to pursue this because the higher output energy may render the machine inoperable for too long. Dealing with a high rate of explosions is one thing this class of fusion will need to solve before being able to generate power. [0]https://en.wikipedia.org/wiki/Fusion_ignition https://en.wikipedia.org/wiki/Fusion_ignition
- dogma1138 5y ago
  Don’t you still need to spend energy on confinement? You don’t need to “reignite” the plasma but w/e confinement solution you chosen still has a cost and a non marginal one when it comes to magnetic confinement.
  - gene-h 5y ago
    this uses inertial confinement rather than magnetic confinement.
    - dogma1138 5y ago
      You still need big ass lasers or particle accelerators for ICF too, these tend to be quite energy intensive too.
    - tsimionescu 5y ago
      Yes, with ICF you do need to constantly reignite the plasma.
- hangonhn 5y ago
  What is the goal of NIF? I've read repeatedly that fusion power isn't their end goal but rather to study inertial confinement. That's fine but why study inertial confinement if not to generate power? I've always been very confused about their goal. I'm a total layman when it comes to this stuff so there's some nuance I'm not understanding. Appreciate any clarification anyone can give.
deleted 5y ago
[deleted]
mlindner 5y ago
Neither, it's inertial confinement fusion, which isn't really seen as a way to a successful commercial reactor (at least not that I've heard of) and is more a tool to study the physics of D-T fusion reaction in a controlled way that's not inside a nuclear bomb. It's a tool for experiments.
- leephillips 5y ago
  You may be surprised to know that there are loads of people working in ICF who think they're working on a plan to supply the world with energy, and have detailed and elaborate designs for commercial ICF reactors, including pellet factories, tritium extraction, and everything. With calculations of the final cost per delivered kW-hour. It’s all a fantasy, but it’s a real research activity, funded by the US DOE (mainly through the NNSA).

Probably just "plasma breakeven" Sabine talks about the issue. [1] https://backreaction.blogspot.com/2021/10/how-close-is-nuclear-fusion-power.html https://backreaction.blogspot.com/2021/10/how-close-is-nucle...

mlindner 5y ago
Sabine actually is completely misleading and misconstrues a bunch of facts. None of these plants are even attempting to have real energy breakeven and spend a ton of energy supplying experiments and unrelated support equipment. They don't even have a method of capturing energy as that's not the point as it would make it harder to test the physics. Additionally these plants have high amounts of "startup energy consumption" that is also factored in to the energy usage but would be amortized out over a long run. Trying to use the absolute power consumption of the experiment as if that's where the state of the art is at for true energy break even is completely wrong. Plasma breakeven is all anyone is really working on. Once you have plasma breakeven you have a self-sustaining heater basically, which then can be used to create energy. The point of an "ignited plasma" is that it's self-sustaining and just pumps out heat, even if most of the energy is used to keep the reaction going.
- tootie 5y ago
  I think her meaning is pretty clear and correct. As much as plasma breakeven may be the entire goal of ITER it's absolutely setting them up for a badly missed public expectation. The day they declare net positive output, the world will ask when we can start building infrastructure and the answer will be "30 more years" and then they'll get their funding yanked forever.
  - mlindner 5y ago
    ITER isn't even possible to create an economic nuclear reactor out of because it's too big. The sheer size of a ITER-sized reactor doesn't get us to economical reactors. ITER is a science experiment, not a commercial reactor design. High-field strength high temperature superconductor based allows much smaller sizes than ITER, but ITER was designed with the technology that was available in the late 1990s.
  - willis936 5y ago
    >As much as plasma breakeven may be the entire goal of ITER Who gave you that impression? They were lying. The goal of ITER has always been to study burning plasmas and experiment with solutions to problems that a reactor-grade MCF machine faces.
- ckuehne 5y ago
  I think your statement "Once you have plasma breakeven you have a self-sustaining heater basically" is false. According to Wikipedia [1] - if I interpret it correctly - the fusion energy gain factor from plasma must be 5 (!) to have a self-sustaining heater: "Most fusion reactions release at least some of their energy in a form that cannot be captured within the plasma, so a system at Q = 1 will cool without external heating. With typical fuels, self-heating in fusion reactors is not expected to match the external sources until at least Q = 5" [1] https://en.wikipedia.org/wiki/Fusion_energy_gain_factor https://en.wikipedia.org/wiki/Fusion_energy_gain_factor
  - mlindner 5y ago
    I oversimplified in that statement, you need more than a factor of 1 because of heat losses to the environment yes. However 5 is not much different than 1. We've gone from 0.0001 only a few years ago to close to 1 now. And btw, you really want more than 5, 10 or 20 ideally, but again, that's not too hard as compared to how far we've come and new reactors will be beyond that soon.
  - willis936 5y ago
    Fusion begets fusion. ITER plans to have high-intensity, relatively short Q=10 shots. If the plasma heats itself then it doesn't need much heating. This sudden focus on Q is clearly the result of one vocal non-expert not understanding the field and everyone listening to them like they have something valuable to teach.
- tsimionescu 5y ago
  > Plasma breakeven is all anyone is really working on. Once you have plasma breakeven you have a self-sustaining heater basically, which then can be used to create energy. The point of an "ignited plasma" is that it's self-sustaining and just pumps out heat, even if most of the energy is used to keep the reaction going. This is dead wrong. First of all, the experiment described here is ICF, in which you have to constantly re-heat new pellets of fuel. Even for MCF, you have to spend inordinate amounts of energy just containing the million kelvins plasma with few kelvin superconducting magnets, and to constantly deliver new D+T into the plasma. If containment fails at any time for any amount of time, your reactor is instantly obliterated. Not to mention, your source of heat only heats up by about half of the energy - the other half is radiated away as hard to capture neutrons, which are almost entirely a waste product. I have no idea why you think that ignited plasma is enough to maintain an energy-producing reactor. Edit: million kelvins should have been billion kelvins...
  - jhgb 5y ago
    > the other half is radiated away as hard to capture neutrons, which are almost entirely a waste product I thought the neutrons were supposed to take away the heat, to be absorbed in layers of water?
    - tsimionescu 5y ago
      Reading more about this, it seems that one of the ideas is indeed to capture the neutrons in a liquid lithium blanket, that would then produce both heat and tritium, and using that heat, that is outside the magnetic confinement, to connect to a turbine. Unfortunately, I believe that the area of actually capturing the energy of the fusion reaction is almost entirely unstudied yet in practice.

jacquesm 5y ago

From TFA: "The pace of improvement in energy output has been rapid, suggesting we may soon reach more energy milestones, such as exceeding the energy input from the lasers used to kick-start the process."

birdman3131 5y ago
These people grew up on Wow and are familiar with Soon™.
- deleted 5y ago
  [deleted]

Cerium 5y ago

I think it is neither. Most nuclear fusion news is focused on magnetic confinement. This article is about reaching ignition on an inertial confinement system.

lisper 5y ago

Neither. From TFA: "While the latest experiment still required more energy in than it got out, it is the first suspected to reach the crucial stage of ‘ignition’, which allowed considerably more energy to be produced than ever before, and paves the way for ‘break even’, where the energy in is matched by the energy out." Here [1] is an excellent video by Sabine Hossenfelder about why you should not get too excited about this result. [1] https://www.youtube.com/watch?v=LJ4W1g-6JiY https://www.youtube.com/watch?v=LJ4W1g-6JiY

mlindner 5y ago
It's neither, agreed. However, Sabine misconstrues things in the opposite direction and lies through omission to the audience. For example including startup energy and not ammortizing it over runtime, or not assuming that the energy consumption of the experiments is part of the required energy consumption of the fusion reactor, or trying to construe that once you have a fusion power reaction that is burning it is still especially difficult to further create a functioning power reactor out of it. The true hard part of fusion is the burning plasma aspect. Once you have a burning plasma, it's a heat source like any other (with a few side-effects like neutron output) and everything we know from fission power reactors (but with a much lower radiation) and fossil fuel generators applies.
- dcow 5y ago
  Where are you getting this impression? Her video pretty clearly focuses on the confusion between the Qs. Where does she get the napkin math wrong? She uses a published figure for total energy required during the operation of ITER when it’s up and running not a one time startup cost figure. Id she misrepresented that number, what would be a more honest total power consumption figure? As far as construing the output, she uses existing loss ratio for heat to electrical energy conversion which really does not seem to work to construe the problem as “especially difficult”, it’s “normally difficult” is how I interpreted. Are there impending advancements in energy conversion that makes 50% too liberal?
  - mlindner 5y ago

gene-h 5y ago

What's important here is that they may have achieved ignition, that is making the fusion reaction self sustaining[0]. Once it becomes self sustaining one should be able to add more fuel to the pellet to get more energy out for the same input energy. It's worth noting that NIF was not intended to generate power and is not representative of a potential power plant. The lasers on NIF are old and were chosen to have a lower efficiency for cost reasons. In addition, while NIF could generate much more energy, NIF isn't necessarily going to pursue this because the higher output energy may render the machine inoperable for too long. Dealing with a high rate of explosions is one thing this class of fusion will need to solve before being able to generate power. [0]https://en.wikipedia.org/wiki/Fusion_ignition https://en.wikipedia.org/wiki/Fusion_ignition

dogma1138 5y ago
Don’t you still need to spend energy on confinement? You don’t need to “reignite” the plasma but w/e confinement solution you chosen still has a cost and a non marginal one when it comes to magnetic confinement.
- gene-h 5y ago
  this uses inertial confinement rather than magnetic confinement.
  - dogma1138 5y ago
    You still need big ass lasers or particle accelerators for ICF too, these tend to be quite energy intensive too.
  - tsimionescu 5y ago
    Yes, with ICF you do need to constantly reignite the plasma.
hangonhn 5y ago
What is the goal of NIF? I've read repeatedly that fusion power isn't their end goal but rather to study inertial confinement. That's fine but why study inertial confinement if not to generate power? I've always been very confused about their goal. I'm a total layman when it comes to this stuff so there's some nuance I'm not understanding. Appreciate any clarification anyone can give.

deleted 5y ago

[deleted]

mlindner 5y ago

Neither, it's inertial confinement fusion, which isn't really seen as a way to a successful commercial reactor (at least not that I've heard of) and is more a tool to study the physics of D-T fusion reaction in a controlled way that's not inside a nuclear bomb. It's a tool for experiments.

leephillips 5y ago
You may be surprised to know that there are loads of people working in ICF who think they're working on a plan to supply the world with energy, and have detailed and elaborate designs for commercial ICF reactors, including pellet factories, tritium extraction, and everything. With calculations of the final cost per delivered kW-hour. It’s all a fantasy, but it’s a real research activity, funded by the US DOE (mainly through the NNSA).