• rumba@lemmy.zipEnglish
    0·
    5 days ago

    I was so hoping helion was going to work. They were trying to recapture the pulse in magnetic confinement when fusion pulsed. Eliminating steam would be awesome.

    • bss03@infosec.pubEnglish
      0·
      5 days ago

      IIRC, most of the people that actually work at ITER don’t expect to live to see commercial fusion.

      We’ve achieved controlled ignition several times, but there’s a lot of steps still between that and delivering fusion power to your local grid, and I don’t think I would trust anyone to give a concrete timeline.

      I really thought Polywell Fusion would be the trick, but Australians (and probably the US DoD) have good evidence it doesn’t “scale” in a way that will give a energy-positive/fuel-negative cycle. https://en.wikipedia.org/wiki/Polywell#University_of_Sydney_experiments

  • taccihcysp@lemmy.dbzer0.comEnglish
    0·
    6 days ago

    Couldn’t you just put some solar panels next to it? I mean, the sun is basically just a massive fusion reactor (just very far away and kind of inefficient), right? Imagine we built our own sun, right here on earth, that would make solar panels a lot more effective, no?

      • how_we_burned@lemmy.zipEnglish
        0·
        6 days ago

        Stars are a lot cooler then fusion reactors.

        It’s in their outer layers that they produce a shit ton of photons.

        Fusion reactors are way hotter (like 100m Celsius) and although they make photons most are very high energy (think gamma, xrays etc).

        So what would be emitted as visible light would never be enough to generate enough power via pvc to pay back the cost of generating the fusion reaction in the first place much less the cost of building the plant.

        Also pvc is like at best 22%~ efficient. You’re losing a lot compared to say steam powered generators which, using ultra super critical hot steam made by a fusion reactor could maybe hit 60% (I believe that is high as you can go).

        Asianonmetry has a great lecture on steam powered generators

        https://youtu.be/suCEKLCCgzw

    • NaibofTabr@infosec.pubEnglish
      0·
      6 days ago

      We can’t make it so large that its own gravity will contain the reaction mass, so it has to be kept inside a very strong magnetic field created by huge magnets. You can’t put solar panels inside the reaction chamber, they would get destroyed.

        • NaibofTabr@infosec.pubEnglish
          0·
          5 days ago

          Um, it’s the heat, pressure, and ionizing radiation of the fusion reaction that would destroy the panels.

    • Warl0k3@lemmy.worldEnglish
      0·
      6 days ago

      Yep! And fun fact, online encryption relies on basically exactly this technology (radioactive decay, not fusion, but hey it’s close enough if you squint). Radiophotovoltaic batteries provide uninterrupted current, which is used to ensure that encryption keys (stored in highly volatile memory for security) are not lost due to a brief power flicker.

    • Flyberius [comrade/them]@hexbear.netEnglish
      0·
      6 days ago

      All depends on the frequency of the radiation it is giving off and the intensity I guess. Probably not the same as what we get from the sun, so I’m guessing solar panels aren’t suitable

    • bort@sopuli.xyzEnglish
      0·
      6 days ago

      except for solar and wind, i guess. also the thingy where you catch electrons directly from nuclear decay.

      • j4yc33@piefed.socialEnglish
        0·
        6 days ago

        There are also some chemical modes of electricity generation (Alkalai batteries, etc). Also using flowing water to move Turbines like dams.

        But then the meme isn’t as fun here, and those are such a small minority of how we generate powers.

    • MinnesotaGoddam@lemmy.worldEnglish
      0·
      6 days ago

      why not do both? get both efficiencies

      [note: this is an example of why i am not currently working in nuclear physics]

      • Warl0k3@lemmy.worldEnglish
        0·
        6 days ago

        That’s the most common proposal for MHD generators - once it goes thru the MHD proper you use the waste heat to drive a conventional powerplant. Unfortunately MHD requires the production of plasma to be effective, and plasma just does not like to exist, so the engineering practicalities make it… unlikely to ever be even remotely viable outside of incredibly niche applications (non-plasma MHD has been studied, and I believe there are even some human trials, to power implants in the body like pacemakers and I remember reading about nervous-interface devices in mice that used arterial MHD on to generate the microcurrent needed)

          • Warl0k3@lemmy.worldEnglish
            0·
            6 days ago

            Worry not, the implanted power systems I know of generate at peak a few nanowatts. Enough to tricklecharge an extremely low power device or run some very very very efficient digital hardware, but no way you’re harvesting that power for anything more useful. It’d be far more practical just to have the humans chained to bicycle generators…

        • MinnesotaGoddam@lemmy.worldEnglish
          0·
          6 days ago

          ooo, i’m trying to keep up on Deep Brain Stimulation research (i want one for reasons. they aren’t doing what i want yet, but in about 5 years they should be there) and that sounds like related research

          • Warl0k3@lemmy.worldEnglish
            0·
            6 days ago

            I’ll admit I’ve been out of the field for a couple years so my information is going to be outdated, but I believe the issue with using MHD for continuous stimulation is that it generates tiny amounts of power - enough to trickle-charge a pacemaker, but not enough to keep tickling the brainstem with the frequency needed in DBS. Hopefully there have been/will be improvements to the tech that I am unaware of!

              • Warl0k3@lemmy.worldEnglish
                0·
                6 days ago

                I think the idea was to provide a redundant method of charging in case you’re unable or forget to recharge it externally. But ideally yes, it would be entirely internally powered so you wouldn’t be tethered to the grid.

                edit:

                A more promising approach is this which is, somewhat unglamorously, just a small turbine implanted into the heart that is spun by bloodflow. oh, no, this is a different study than the one I was thinking of! This uses a flexible generator that generates power from the deformation of the Vena Cava. Fascinating, I’ll have to dig thru it.

                • MinnesotaGoddam@lemmy.worldEnglish
                  0·
                  6 days ago

                  now that is a novel use of piezoelectricity. whoever thought of that needs many sloppy kisses from many cats

                  personally i think they just need to design for the battery run at 80% capacity and let it wear down. although i can see why they might need to periodically replace a foreign object implanted in the body. i had to get all the titanium plates and screws removed eventually because ow.

      • FuglyDuck@lemmy.worldEnglish
        0·
        6 days ago

        Well, not an engineer myself, either, but generally speaking that would greatly increase the systems complexity, which generally increases maintenance costs, down time, and the initial cost of the system.

        You might be able to eke out a bit more power, but there’s more to the decision than total output and how efficient it is.

        What I would imagine were a fusion-powered MHD being useful would be as a front end to fusion-based plasma propulsion. (Basically something like the VSIMR, Hall effect or whatever plasma thruster, where the fusion reaction generates both some power to create the thrust and its exhaust plasma is also the reaction mass.(I mentioned I’m not an engineer… right? Just an incorrigible nerd who likes sci-fi.)

        • GreenCrunch@piefed.blahaj.zoneEnglish
          0·
          6 days ago

          There’s a few things (I am an engineer, though not nuclear):

          1. Efficiencies don’t necessarily stack like that. For boiling water you’re dependent on kinetic energy as heat. I’m not familiar with running plasma through magnetic fields for power generation, but if you lose thermal energy, your overall efficiency may be worse.
          2. In power generation, reliability is obviously extremely important, and the nuclear industry is highly risk-averse. So doing something in a known, tested way is preferable. Any downtime is extremely expensive if things break, since it may be gigawatts of power you’re not selling.
          3. Big magnets and handling highly energetic plasma are both really expensive. Steam turbines and generators have existing supply chains since we use them everywhere. I think cost is a big part, since the people building power plants want to make their money back sooner, so may not want to pay millions to billions more for a few percent efficiency gain.
  • FackCurs@lemmy.worldEnglish
    0·
    6 days ago

    If they make an artificial sun inside a donut why don’t they line the donut with solar panels? Are they stupid?

    • Warl0k3@lemmy.worldEnglish
      0·
      6 days ago

      Real answer: The sheer amount of neutron radiation thrown off by fusion would mechanically erode the panels. This is why the Lockheed Martin fusion reactor they claimed to have built is complete BS - their design ignored the requirement to shield their superconductors from the neutron radiation, allowing them to be placed far closer to the reaction (and thus vastly lower the power requirements). While it could have theoretically worked briefly, it would have eaten itself into radioactive dust astoundingly quickly.

    • ByteJunk@lemmy.worldEnglish
      0·
      6 days ago

      But you’d have to allow the sun to leak out of the donut, and I’m not too sure that sun-leaking donuts are OSHA approved.