3 ms·

Some context on why progress slowed: From the 60s to the 80s we got pretty good at tokamaks (stellarators have been catching up since we got computers) but Mag

Some context on why progress slowed: From the 60s to the 80s we got pretty good at tokamaks (stellarators have been catching up since we got computers) but Magnetic Confinement Fusion (MCF) triple product performance scales with major radius ^ 1.3 and confinement field strength ^ 3. Power density scales linearly with major radius and with the magnetic field strength ^ 4. At some point increasing the major radius becomes extremely expensive, so pushing past the barrier of Q=1 has been a long, political process. At the same time a real burning plasma (Q>1) machine has a lot of added cost to operate a nuclear facility (tritium handling and neutron radiation). So there has never been a physics barrier to Q>1, but an economic one. What's changed in the past year is that REBCO manufacturing and working matured to the point that confinement fields are now twice as strong as they used to be. Suddenly building a burning plasma machine isn't a 40 year international venture and economically viable MCF plants are in the crosshairs.

prox 4y ago
I don’t know a whole lot about fusions latest and greatest. Thanks for putting it into context. So could we have had a working fusion machine with infinite money and political will? Also what is your prognosis of the next 5 or 10 years?
- willis936 4y ago
  Infinite money is a weird concept. It doesn't matter how much money humans print, what matters is what humans can accomplish. If we eliminated the concept of money we still would not be able to power mankind on 100 meter tall machines because we don't have the resources to build them quickly. There are sound practical and theoretical reasons for keeping "minimize the levelized cost of electricity" be the first goal of any alternate power source. My prognosis is that CFS is on a good track and that their state goals are achievable. There's going to be some big headlines in a few years. If other startups also hit their goals we'll likely see a race with private investment. Public interest and government funding will likely lag the private progress by a few years.
  - ianai 4y ago
    What are the resources missing to build them quickly?
    - willis936 4y ago
      Existing industries and throughput. We could divert steel production (as an example, but applied to other raw materials) away from unnecessary (defense) applications, but even with monetary incentive you need to scale up the ability of humans to create megaprojects. Minimizing the size of the project not only minimizes the cost, but also maximizes our ability to make them faster. Given a choice between the two: I'd take the latter. We don't really have that choice though because we (humans) have not cracked the code to successful megaprojects on budget and on time every time.
      - WillPostForFood 4y ago
        We could divert steel production (as an example, but applied to other raw materials) away from unnecessary (defense) applications Defense uses only 3% of US steel production. That’s not the problem, and arguably, necessary. https://www.commerce.gov/sites/default/files/department_of_defense_memo_response_to_steel_and_aluminum_policy_recommendations.pdf https://www.commerce.gov/sites/default/files/department_of_d...
        pstuart 4y ago
        Defense is necessary, but I'm guessing the DoD is not a paragon of efficiency.
        throwaway290 4y ago
        I suppose if we were talking about infinite money and political will we might as well simplify the problem to an ideal spherical world in vacuum where there are no rogue dictators and the whole world cooperates (=> defense is unnecessary). Would we be able to build them then?
    - roenxi 4y ago
AtlasBarfed 4y ago
"economically viable" what is the price target here? If it is 2022 solar and wind LCOE cost, and you are targetting, say, 20 years to build a plant, then those aren't viable targets. Solar and wind will probably drop another 50% or more by then in LCOE cost. It's worth research, sure. But the same issues of new-gen nuclear are shared with any fusion, except fusion is way further down the prototype stage. Solar/Wind/Battery is already near-price competitive with natural gas turbine unsubsidized (and they never seem to account for all the hidden fossil fuel subsidies), and the curves are still in prime economies of scale improvement.
- witherk 4y ago
  Maybe I'm wrong, but I hope that fusion wouldn't have the problems with NIMBY-ism that fission has. At least not to the same extent.
beambot 4y ago
For those who are curious about SPARC and CFS (Commonwealth Fusion Systems), this lecture by Dr. Whyte covers the salient points: > Small, modular & economically attractive fusion enabled by high-field superconductors https://www.youtube.com/watch?v=rY6U4wB-oYM https://www.youtube.com/watch?v=rY6U4wB-oYM

prox 4y ago

I don’t know a whole lot about fusions latest and greatest. Thanks for putting it into context. So could we have had a working fusion machine with infinite money and political will? Also what is your prognosis of the next 5 or 10 years?

willis936 4y ago
Infinite money is a weird concept. It doesn't matter how much money humans print, what matters is what humans can accomplish. If we eliminated the concept of money we still would not be able to power mankind on 100 meter tall machines because we don't have the resources to build them quickly. There are sound practical and theoretical reasons for keeping "minimize the levelized cost of electricity" be the first goal of any alternate power source. My prognosis is that CFS is on a good track and that their state goals are achievable. There's going to be some big headlines in a few years. If other startups also hit their goals we'll likely see a race with private investment. Public interest and government funding will likely lag the private progress by a few years.
- ianai 4y ago
  What are the resources missing to build them quickly?
  - willis936 4y ago
    Existing industries and throughput. We could divert steel production (as an example, but applied to other raw materials) away from unnecessary (defense) applications, but even with monetary incentive you need to scale up the ability of humans to create megaprojects. Minimizing the size of the project not only minimizes the cost, but also maximizes our ability to make them faster. Given a choice between the two: I'd take the latter. We don't really have that choice though because we (humans) have not cracked the code to successful megaprojects on budget and on time every time.
    - WillPostForFood 4y ago
      We could divert steel production (as an example, but applied to other raw materials) away from unnecessary (defense) applications Defense uses only 3% of US steel production. That’s not the problem, and arguably, necessary. https://www.commerce.gov/sites/default/files/department_of_defense_memo_response_to_steel_and_aluminum_policy_recommendations.pdf https://www.commerce.gov/sites/default/files/department_of_d...
      - pstuart 4y ago
        Defense is necessary, but I'm guessing the DoD is not a paragon of efficiency.
      - throwaway290 4y ago
        I suppose if we were talking about infinite money and political will we might as well simplify the problem to an ideal spherical world in vacuum where there are no rogue dictators and the whole world cooperates (=> defense is unnecessary). Would we be able to build them then?
  - roenxi 4y ago

AtlasBarfed 4y ago

"economically viable" what is the price target here? If it is 2022 solar and wind LCOE cost, and you are targetting, say, 20 years to build a plant, then those aren't viable targets. Solar and wind will probably drop another 50% or more by then in LCOE cost. It's worth research, sure. But the same issues of new-gen nuclear are shared with any fusion, except fusion is way further down the prototype stage. Solar/Wind/Battery is already near-price competitive with natural gas turbine unsubsidized (and they never seem to account for all the hidden fossil fuel subsidies), and the curves are still in prime economies of scale improvement.

witherk 4y ago
Maybe I'm wrong, but I hope that fusion wouldn't have the problems with NIMBY-ism that fission has. At least not to the same extent.

beambot 4y ago

For those who are curious about SPARC and CFS (Commonwealth Fusion Systems), this lecture by Dr. Whyte covers the salient points: > Small, modular & economically attractive fusion enabled by high-field superconductors https://www.youtube.com/watch?v=rY6U4wB-oYM https://www.youtube.com/watch?v=rY6U4wB-oYM