5 ms·

It will be interesting to see if this helps solve the tritium/helium 3 problem that all current fusion companies face. I’ve always found it interesting that th

by RC_ITR 3y ago

It will be interesting to see if this helps solve the tritium/helium 3 problem that all current fusion companies face. I’ve always found it interesting that they are allowed to pitch VCs claiming that they are doing the same thing the sun does, when the sun in fact does proton/proton, proton/deuterium, and helium 3/helium 3 fusion at a relatively slow rate under extremely high pressure.

wheelerof4te 3y ago
"when the sun in fact does proton/proton, proton/deuterium, and helium 3/helium 3 fusion at a relatively slow rate under extremely high pressure." We actually don't know how the Sun does fusion. If we did, we'd have created it here on Earth already.
- ryanpandya 3y ago
  I thought we're pretty clear that it's thanks to absolutely colossal mass, which... Can't really happen on earth since it requires the mass of a huge number of earths.
  - wheelerof4te 3y ago
    Then we need to find another way to generate fusion power, or admit that it's impossible to do on this planet. Throwing lumps of cash at fusion power venture capital feels almost like a money-laundering fraud.
    - varjag 3y ago
      The whole fusion energy effort since 1950s is about finding another way.
    - Maken 3y ago
      At least it's not crypto and it's not actively hurting anyone.
      - RC_ITR 3y ago
        Until the tritium leaks...
    - ben_w 3y ago
      > Then we need to find another way to generate fusion power, or admit that it's impossible to do on this planet. Yes. Here are the currently known alternatives off the top of my head: * Fusion bomb * Inertial electrostatic confinement (14 year olds have done this for highschool science fair projects) * Virtual cathodes (Polywell, technically also an IEC variant) * Magnetic confinement (Tokamaks: the big expensive doughnuts) * Field-reversed configuration (technically also magnetic, but these are magnetic "smoke rings", Helion Energy does this) * Z-pinch (again magnetic, but different) * Laser confinement (NIF) * Muon-catalyzed fusion (no chance of this becoming mainstream unless we can convince muons to stop decaying) IIRC all of these have demonstrated that it's physically possible; some even show promise. (I've been wanting to write a plasma physics simulation to see if I can improve on the Fusor design since I was at university; now chatGPT writes acceptable code, I keep asking myself why I've not yet made this happen…)
- andruby 3y ago
  There’s a difference between knowing the physical and chemical reactions and being able to reproduce it. We have reproduced it, but not yet sustainably and in an economically profitable way. We can’t reproduce exactly what the sun is doing, because we don’t want the whole planet to run fusion. One of the large problems to solve, as I understand it, is containment. No need for containment on the sun.
  - simiones 3y ago
    > One of the large problems to solve, as I understand it, is containment. No need for containment on the sun. Containment, in the context of fusion, doesn't refer to preventing the reaction from running rampant. It refers to keeping the reactants in a small confined space so the reaction can continue at all. The sun achieves this containment through the least efficient means: it's gigantic mass means that the reactants are forced together by the force of gravity. Plus, the shear quantity of superhot plasma helps ensure that energetic particles have an excellent chance to hit another core, keeping the reaction going. Note that the solar core, where the vast majority of solar fusion happens, is ~0.25 of the sun's radius, so ~25 Earth radii. Quite hard to get the amount of plasma on Earth. The entirety of the Earth doesn't have even a fraction of the Sun's mass, so that is impossible to reproduce. So we need to rely on much more violent forces to achieve a similar level of containment as the Sun.
- ben_w 3y ago
  > We actually don't know how the Sun does fusion. If we did, we'd have created it here on Earth already. We know we can't do what the sun does here on Earth, and we also know that we don't want to what the sun does. We can't, because the cube-square law means the sun stays hot enough for long enough for this to happen even though a reactor on the ground would cool down almost immediately. We don't want to, because the reaction happens over the course of billions of years giving the sun a specific power output similar to rotting cabbages.
simiones 3y ago
Given that this is a new form of cold fusion, this is merely bad science and will not "solve" anything. Shameful for NASA of all places to spend money on such a hoax.
- ouid 3y ago
  [dead]
DennisP 3y ago
That's not an actual problem. To breed tritium, bombard lithium with the neutrons from D-T fusion. To breed helium-3, fuse deuterium.
- RC_ITR 3y ago
  It is a problem unless I can borrow your Tokamak that can do D-D fusion at 300mn degrees C without insane energy losses. And as for breeding tritium - I think you're skipping a few steps. D-T fusion gives you 1 neutron, which is enough to make 1 tritium isotope from Li6 (7.5% of global Lithium supply). Sure you can use neutron multipliers like Be (otherwise, anything less that 100% neutron capture depletes the supply), but how much energy are you losing then (since keep in mind, 80% of the D-T energy is that neutron to begin with)? And beyond all of that, it's a problem unless you can show me your breeding blanket design and the system you plan to use to capture the radioactive gaseous tritium in a way that doesn't poison any water supplies (keep in mind, as one of the smallest and most buoyant gases, it's really hard to contain hydrogen without noticeable leakage). Anyway, once those issues are ironed out, sure it's not a problem, but it's a huge problem today.
  - DennisP 3y ago
    You don't need to breed He3 unless you can get net power from D-He3. If you can do that, then you can probably also get net power from D-D, which doesn't require as high a triple product. The fusion company Helion is working on exactly this, and attempting net power in 2024 with an FRC design. Breeding tritium doesn't make the neutron's kinetic energy disappear, or convert into matter. Neither does multiplying neutrons; you just get two neutrons whose combined kinetic energy sums up to that of the original neutron. In the end, as usual, the energy mostly ends up as heat. I'll grant you tritium capture. Several of the private companies use a molten breeding blanket (CFS, Zap Energy, and General Fusion, possibly others), so at least the tritium won't be trapped in the blanket.
    - RC_ITR 3y ago
      In your first paragraph what are you even saying? If you make one complex fusion reaction work then a different one is cake? I don't think helions “smash the plasma linearly” design even works for D-D. Their quartz containment chamber definitely is a weird set up for D-D. I’m aware of what Helion is trying to do and wish them luck, but they won’t even release data on their supposed He3 reactions, so I’m guessing they’re not light years ahead on D-D and ready to use their very customized tech for a different reaction quite yet. As for your very salient point on where the energy goes, what are you heating? Your new Tritium. So now you not only have to capture the tritium but you have to extract its heat to generate electricity? Or are you just capturing heat from the helium and whatever is absorbed by the rest of the blanket? No startups use a breeding blanket in 2023. They just talk about them. All the designs are still very much in prototype phase and nobody has blanket IP because they barely have reactor IP (though lots of cool magnet patents!) In fact if they did have breeding blankets, they could actually make some money selling their tritium!

by RC_ITR 3y ago

wheelerof4te 3y ago

"when the sun in fact does proton/proton, proton/deuterium, and helium 3/helium 3 fusion at a relatively slow rate under extremely high pressure." We actually don't know how the Sun does fusion. If we did, we'd have created it here on Earth already.

ryanpandya 3y ago
I thought we're pretty clear that it's thanks to absolutely colossal mass, which... Can't really happen on earth since it requires the mass of a huge number of earths.
- wheelerof4te 3y ago
  Then we need to find another way to generate fusion power, or admit that it's impossible to do on this planet. Throwing lumps of cash at fusion power venture capital feels almost like a money-laundering fraud.
  - varjag 3y ago
    The whole fusion energy effort since 1950s is about finding another way.
  - Maken 3y ago
    At least it's not crypto and it's not actively hurting anyone.
    - RC_ITR 3y ago
      Until the tritium leaks...
  - ben_w 3y ago
    > Then we need to find another way to generate fusion power, or admit that it's impossible to do on this planet. Yes. Here are the currently known alternatives off the top of my head: * Fusion bomb * Inertial electrostatic confinement (14 year olds have done this for highschool science fair projects) * Virtual cathodes (Polywell, technically also an IEC variant) * Magnetic confinement (Tokamaks: the big expensive doughnuts) * Field-reversed configuration (technically also magnetic, but these are magnetic "smoke rings", Helion Energy does this) * Z-pinch (again magnetic, but different) * Laser confinement (NIF) * Muon-catalyzed fusion (no chance of this becoming mainstream unless we can convince muons to stop decaying) IIRC all of these have demonstrated that it's physically possible; some even show promise. (I've been wanting to write a plasma physics simulation to see if I can improve on the Fusor design since I was at university; now chatGPT writes acceptable code, I keep asking myself why I've not yet made this happen…)
andruby 3y ago
There’s a difference between knowing the physical and chemical reactions and being able to reproduce it. We have reproduced it, but not yet sustainably and in an economically profitable way. We can’t reproduce exactly what the sun is doing, because we don’t want the whole planet to run fusion. One of the large problems to solve, as I understand it, is containment. No need for containment on the sun.
- simiones 3y ago
  > One of the large problems to solve, as I understand it, is containment. No need for containment on the sun. Containment, in the context of fusion, doesn't refer to preventing the reaction from running rampant. It refers to keeping the reactants in a small confined space so the reaction can continue at all. The sun achieves this containment through the least efficient means: it's gigantic mass means that the reactants are forced together by the force of gravity. Plus, the shear quantity of superhot plasma helps ensure that energetic particles have an excellent chance to hit another core, keeping the reaction going. Note that the solar core, where the vast majority of solar fusion happens, is ~0.25 of the sun's radius, so ~25 Earth radii. Quite hard to get the amount of plasma on Earth. The entirety of the Earth doesn't have even a fraction of the Sun's mass, so that is impossible to reproduce. So we need to rely on much more violent forces to achieve a similar level of containment as the Sun.
ben_w 3y ago
> We actually don't know how the Sun does fusion. If we did, we'd have created it here on Earth already. We know we can't do what the sun does here on Earth, and we also know that we don't want to what the sun does. We can't, because the cube-square law means the sun stays hot enough for long enough for this to happen even though a reactor on the ground would cool down almost immediately. We don't want to, because the reaction happens over the course of billions of years giving the sun a specific power output similar to rotting cabbages.

simiones 3y ago

Given that this is a new form of cold fusion, this is merely bad science and will not "solve" anything. Shameful for NASA of all places to spend money on such a hoax.

ouid 3y ago
[dead]

DennisP 3y ago

That's not an actual problem. To breed tritium, bombard lithium with the neutrons from D-T fusion. To breed helium-3, fuse deuterium.

RC_ITR 3y ago
It is a problem unless I can borrow your Tokamak that can do D-D fusion at 300mn degrees C without insane energy losses. And as for breeding tritium - I think you're skipping a few steps. D-T fusion gives you 1 neutron, which is enough to make 1 tritium isotope from Li6 (7.5% of global Lithium supply). Sure you can use neutron multipliers like Be (otherwise, anything less that 100% neutron capture depletes the supply), but how much energy are you losing then (since keep in mind, 80% of the D-T energy is that neutron to begin with)? And beyond all of that, it's a problem unless you can show me your breeding blanket design and the system you plan to use to capture the radioactive gaseous tritium in a way that doesn't poison any water supplies (keep in mind, as one of the smallest and most buoyant gases, it's really hard to contain hydrogen without noticeable leakage). Anyway, once those issues are ironed out, sure it's not a problem, but it's a huge problem today.
- DennisP 3y ago
  You don't need to breed He3 unless you can get net power from D-He3. If you can do that, then you can probably also get net power from D-D, which doesn't require as high a triple product. The fusion company Helion is working on exactly this, and attempting net power in 2024 with an FRC design. Breeding tritium doesn't make the neutron's kinetic energy disappear, or convert into matter. Neither does multiplying neutrons; you just get two neutrons whose combined kinetic energy sums up to that of the original neutron. In the end, as usual, the energy mostly ends up as heat. I'll grant you tritium capture. Several of the private companies use a molten breeding blanket (CFS, Zap Energy, and General Fusion, possibly others), so at least the tritium won't be trapped in the blanket.
  - RC_ITR 3y ago
    In your first paragraph what are you even saying? If you make one complex fusion reaction work then a different one is cake? I don't think helions “smash the plasma linearly” design even works for D-D. Their quartz containment chamber definitely is a weird set up for D-D. I’m aware of what Helion is trying to do and wish them luck, but they won’t even release data on their supposed He3 reactions, so I’m guessing they’re not light years ahead on D-D and ready to use their very customized tech for a different reaction quite yet. As for your very salient point on where the energy goes, what are you heating? Your new Tritium. So now you not only have to capture the tritium but you have to extract its heat to generate electricity? Or are you just capturing heat from the helium and whatever is absorbed by the rest of the blanket? No startups use a breeding blanket in 2023. They just talk about them. All the designs are still very much in prototype phase and nobody has blanket IP because they barely have reactor IP (though lots of cool magnet patents!) In fact if they did have breeding blankets, they could actually make some money selling their tritium!