6 ms·

heh, you're right, look at all these idiots who don't know it's dumb like we do. he he he... (why do we think it's dumb again?)

pfdietz 5y ago
Because it's a non sequitur. The metric of "energy/mass of fuel" has nothing to do with why any actual consumer would consider the source to be better. Metrics like cost, safety, pollution, etc. are relevant; that metric is not.
- ncmncm 5y ago
  And, thus far, fusion yields exactly zero joules of useful energy (unless you count solar). It hasn't even vaporized anybody yet, never mind anybody you might have wanted to have vaporized. (Tokamak) fusion will never produce commercially competitive energy. Every plausible system design would be overwhelmingly more expensive to build and operate than a fission plant of similar rating. And, fission is already not competitive, and gets less so every day. (I still hold out hope for FRC De-He3 fusion for space probe propulsion--4 years to Pluto--but Tokamak eats all the research dollars, so who knows if we will ever find out?)
  - pfdietz 5y ago
    > I still hold out hope Well, Helion did just get $500M in funding, and is very close to that design space. I have doubts about Helion being able to do it, but if I had to invest in fusion it would be them (and just possibly Zap). Going beyond DT and recovering energy electromagnetically addresses the engineering/economic showstoppers that make things like tokamaks burning DT seem like a dead end.
    - runnerup 5y ago
      Why do you pick Helion over Commonwealth Fusion Systems?
      - pfdietz 5y ago
        Helion is using a FRC (Field Reversed Configuration), which was what I was responding to. Also: Helion is taking a riskier physics approach in order to reduce engineering difficulty. I consider this a very good idea. Ordinary DT reactors make heat (80% of the energy comes off in neutrons, the energy of which gets turned to heat in a blanket.) Fission reactors should be able to make heat more easily and cheaply, so what is the point? Helion's approach, on the other hand, has plasma energy converted directly to electrical energy by expanding against a magnetic field. If this can be made to work, it means the non-nuclear side of a fusion power plant can be made much smaller (ideally, turbines/heat exchangers/cooling towers could be avoided entirely; realistically they could be made much smaller for a given plant power output). Their fuel choice (DD, D3He), while much more difficult to burn, subjects the materials of the reactor to much less radiation damage. There is a realistic chance the first wall of a D3He reactor could last the life of the power plant.
      - ncmncm 5y ago
        Tokamak, dead end.
- grayhatter 5y ago
  what about rockets?
  - pfdietz 5y ago
    Either the fusion fuel gets mixed with so much inert material that the mass of the fuel doesn't matter, or the reactor is so massive compared to the fuel that again the fuel mass doesn't much matter.

pfdietz 5y ago

Because it's a non sequitur. The metric of "energy/mass of fuel" has nothing to do with why any actual consumer would consider the source to be better. Metrics like cost, safety, pollution, etc. are relevant; that metric is not.

ncmncm 5y ago
And, thus far, fusion yields exactly zero joules of useful energy (unless you count solar). It hasn't even vaporized anybody yet, never mind anybody you might have wanted to have vaporized. (Tokamak) fusion will never produce commercially competitive energy. Every plausible system design would be overwhelmingly more expensive to build and operate than a fission plant of similar rating. And, fission is already not competitive, and gets less so every day. (I still hold out hope for FRC De-He3 fusion for space probe propulsion--4 years to Pluto--but Tokamak eats all the research dollars, so who knows if we will ever find out?)
- pfdietz 5y ago
  > I still hold out hope Well, Helion did just get $500M in funding, and is very close to that design space. I have doubts about Helion being able to do it, but if I had to invest in fusion it would be them (and just possibly Zap). Going beyond DT and recovering energy electromagnetically addresses the engineering/economic showstoppers that make things like tokamaks burning DT seem like a dead end.
  - runnerup 5y ago
    Why do you pick Helion over Commonwealth Fusion Systems?
    - pfdietz 5y ago
      Helion is using a FRC (Field Reversed Configuration), which was what I was responding to. Also: Helion is taking a riskier physics approach in order to reduce engineering difficulty. I consider this a very good idea. Ordinary DT reactors make heat (80% of the energy comes off in neutrons, the energy of which gets turned to heat in a blanket.) Fission reactors should be able to make heat more easily and cheaply, so what is the point? Helion's approach, on the other hand, has plasma energy converted directly to electrical energy by expanding against a magnetic field. If this can be made to work, it means the non-nuclear side of a fusion power plant can be made much smaller (ideally, turbines/heat exchangers/cooling towers could be avoided entirely; realistically they could be made much smaller for a given plant power output). Their fuel choice (DD, D3He), while much more difficult to burn, subjects the materials of the reactor to much less radiation damage. There is a realistic chance the first wall of a D3He reactor could last the life of the power plant.
    - ncmncm 5y ago
      Tokamak, dead end.
grayhatter 5y ago
what about rockets?
- pfdietz 5y ago
  Either the fusion fuel gets mixed with so much inert material that the mass of the fuel doesn't matter, or the reactor is so massive compared to the fuel that again the fuel mass doesn't much matter.