4 ms·

Fusion is safe, clean, produces no waste, runs 24/7 on demand, and after startup costs should be cheap, assuming repairs and maintenance aren't enormously costl

Fusion is safe, clean, produces no waste, runs 24/7 on demand, and after startup costs should be cheap, assuming repairs and maintenance aren't enormously costly. Not to mention, more space efficient than wind or solar. You don't need a particular environemt for it like hydro. No more minig/drilling for energy. No more emissions. No toxic waste. No hourly power variability. No need for batteries. Fusion is the perfect energy source on paper, if it ever becomes a reality.

popotamonga 8y ago
I wonder about politics. No country needs another country for energy anymore. Hum...
ben_w 8y ago
D+D => 2% He4, 49% T (radioactive) + proton, 49% He3 + neutron (to a first approximation, the only radiation which makes almost everything else radioactive). All tritium-based reactions require a steady manufacture of tritium because the half life is too short. All He3-based reactions either require it to be manufactured (conveniently it’s the decay product of tritium, unfortunately see the earlier paragraph for side effects), or mined — from a gas giant, because despite the meme, concentrations on the moon are so low that it makes more sense to turn moon rock into plasma, separate by isotope in a cyclotron, condense the metal into cylinders, catapult the cylinders to earth, and the burn the cylinders in a repurposed coal plant. Even if you want to call fusion “clean” because you can design it so the radioisotopes the neutron activation gives you are mostly benign, or because you’re hoping for an aneutronic reaction like P-B11, it’s still a proliferation hazard. On the other hand, I’d love to see a rocket made from an open-ended fusion reactor.
- aaron_m04 8y ago
  Can't tritium be bred in the reactor walls from lithium?
  - ben_w 8y ago
    Yes, by absorbing neutrons. It’s a good use for the neutrons, but neutrons (and any source of them) are both a hazard in themselves and a proliferation risk.
- candiodari 8y ago
  Fusion is an energy source. Like any other energy source it's automatically also a weapon. All energy sources have historically saved many more lives than they ever cost, including nuclear power. And even solar power is a weapon: https://en.wikipedia.org/wiki/Archimedes#Heat_ray https://en.wikipedia.org/wiki/Archimedes#Heat_ray
  - ben_w 8y ago
    Yes. Unfortunately, despite the fact that even current nuclear causes less deaths per GWh than anything else including solar, it’s also the only power source currently offering humanity a self-made extinction apocalypse. (Also the heat mirror was debunked twice by Mythbusters, as referenced in your own link).
    - candiodari 8y ago
      True, but that's only because it's a really good power source. For instance, it's also what allows us to have working devices outside our solar system, and for similar reasons. Any really good power source will have this problem, as will a great many other technologies, should we have them.
      - ben_w 8y ago
        Indeed. I would rather we had mass interplanetary/lunar colonisation before making interstellar propulsion, for that very reason.
bewo001 8y ago
"after startup cost" is the elephant in the room. [this](https://www.sciencedirect.com/science/article/pii/S0360544218305395 https://www.sciencedirect.com/science/article/pii/S036054421...) estimates a price of 59.31$ / MWh for the proposed DEMO2 fusion reactor. 34 $ of this is depreciation, ie construction cost. Wind power is currently at 20$ / MWh..
- pfdietz 8y ago
  Estimates like that for fusion reactors are utterly preposterous. That's a fraction of the cost of a fission powerplant, even those the fusion plant will be much larger and more complex.

popotamonga 8y ago

I wonder about politics. No country needs another country for energy anymore. Hum...

ben_w 8y ago

D+D => 2% He4, 49% T (radioactive) + proton, 49% He3 + neutron (to a first approximation, the only radiation which makes almost everything else radioactive). All tritium-based reactions require a steady manufacture of tritium because the half life is too short. All He3-based reactions either require it to be manufactured (conveniently it’s the decay product of tritium, unfortunately see the earlier paragraph for side effects), or mined — from a gas giant, because despite the meme, concentrations on the moon are so low that it makes more sense to turn moon rock into plasma, separate by isotope in a cyclotron, condense the metal into cylinders, catapult the cylinders to earth, and the burn the cylinders in a repurposed coal plant. Even if you want to call fusion “clean” because you can design it so the radioisotopes the neutron activation gives you are mostly benign, or because you’re hoping for an aneutronic reaction like P-B11, it’s still a proliferation hazard. On the other hand, I’d love to see a rocket made from an open-ended fusion reactor.

aaron_m04 8y ago
Can't tritium be bred in the reactor walls from lithium?
- ben_w 8y ago
  Yes, by absorbing neutrons. It’s a good use for the neutrons, but neutrons (and any source of them) are both a hazard in themselves and a proliferation risk.
candiodari 8y ago
Fusion is an energy source. Like any other energy source it's automatically also a weapon. All energy sources have historically saved many more lives than they ever cost, including nuclear power. And even solar power is a weapon: https://en.wikipedia.org/wiki/Archimedes#Heat_ray https://en.wikipedia.org/wiki/Archimedes#Heat_ray
- ben_w 8y ago
  Yes. Unfortunately, despite the fact that even current nuclear causes less deaths per GWh than anything else including solar, it’s also the only power source currently offering humanity a self-made extinction apocalypse. (Also the heat mirror was debunked twice by Mythbusters, as referenced in your own link).
  - candiodari 8y ago
    True, but that's only because it's a really good power source. For instance, it's also what allows us to have working devices outside our solar system, and for similar reasons. Any really good power source will have this problem, as will a great many other technologies, should we have them.
    - ben_w 8y ago
      Indeed. I would rather we had mass interplanetary/lunar colonisation before making interstellar propulsion, for that very reason.

bewo001 8y ago

"after startup cost" is the elephant in the room. [this](https://www.sciencedirect.com/science/article/pii/S0360544218305395 https://www.sciencedirect.com/science/article/pii/S036054421...) estimates a price of 59.31$ / MWh for the proposed DEMO2 fusion reactor. 34 $ of this is depreciation, ie construction cost. Wind power is currently at 20$ / MWh..

pfdietz 8y ago
Estimates like that for fusion reactors are utterly preposterous. That's a fraction of the cost of a fission powerplant, even those the fusion plant will be much larger and more complex.