4 ms·

Engineering work halted 30+ years ago. There has been no recent work on structural materials that could withstand the neutron bombardment, and no work on extrac

by ncmncm 4y ago

Engineering work halted 30+ years ago. There has been no recent work on structural materials that could withstand the neutron bombardment, and no work on extracting bred tritium at parts per billion concentration from thousands of tons of "blanket" material needed for the next day's operation. There is no possibility of any present scheme operating at even 10x the cost of fission. Fission is not today competitive, and falls further behind each day.

fallingknife 4y ago
You can get around the tritium problem with boron-proton fusion. Also gets around the inefficiency of converting to heat / turbines. Obviously not any closer to production (and probably further) than tritium fusion, though. https://hb11.energy/how-it-works/ https://hb11.energy/how-it-works/
- ncmncm 4y ago
  There is no reason to expect that p-11B fusion is possible. It might be, in a hundred years, if our present understanding is wrong, and somebody figures out how to reflect gamma rays.
  - fallingknife 4y ago
    It's been done by firing lasers at a HB pellet, so I assume you mean not possible to be done commercially? And why would you have to reflect gamma rays?
    - ncmncm 4y ago
      Obviously you can fuse about anything by accelerating nuclei at each other fast enough. If it takes more energy to do it than you can get back, it is of purely academic interest. Firing lasers comes up many orders of magnitude short. Another alternative is magnetic confinement, but radiative loss goes up with the 4th power of temperature, so would be 10000 times as much as for a D-T plasma, IIUC.
    - pfdietz 4y ago
      Are you talking about the company H11B? Their scheme has been soundly criticized in the literature as not working by a factor of ~100.
JumpCrisscross 4y ago
> Engineering work halted 30+ years ago. There has been no recent work on structural materials that could withstand the neutron bombardment We've made massive strides compacting designs, thereby transforming their unit-economic envelope, using low-temperature superconducting magnets. Those magnets continue to improve, driving potential gains in designs faster than experiments can be funded and built. Optimizing for structural materials, or even blanket versus replaceable structure, seems premature when we don't know the parameters or even type of bombardment we'd be working with.
- ncmncm 4y ago
  Bombardment is with hot neutrons. Period.

by ncmncm 4y ago

fallingknife 4y ago

You can get around the tritium problem with boron-proton fusion. Also gets around the inefficiency of converting to heat / turbines. Obviously not any closer to production (and probably further) than tritium fusion, though. https://hb11.energy/how-it-works/ https://hb11.energy/how-it-works/

ncmncm 4y ago
There is no reason to expect that p-11B fusion is possible. It might be, in a hundred years, if our present understanding is wrong, and somebody figures out how to reflect gamma rays.
- fallingknife 4y ago
  It's been done by firing lasers at a HB pellet, so I assume you mean not possible to be done commercially? And why would you have to reflect gamma rays?
  - ncmncm 4y ago
    Obviously you can fuse about anything by accelerating nuclei at each other fast enough. If it takes more energy to do it than you can get back, it is of purely academic interest. Firing lasers comes up many orders of magnitude short. Another alternative is magnetic confinement, but radiative loss goes up with the 4th power of temperature, so would be 10000 times as much as for a D-T plasma, IIUC.
  - pfdietz 4y ago
    Are you talking about the company H11B? Their scheme has been soundly criticized in the literature as not working by a factor of ~100.

JumpCrisscross 4y ago

> Engineering work halted 30+ years ago. There has been no recent work on structural materials that could withstand the neutron bombardment We've made massive strides compacting designs, thereby transforming their unit-economic envelope, using low-temperature superconducting magnets. Those magnets continue to improve, driving potential gains in designs faster than experiments can be funded and built. Optimizing for structural materials, or even blanket versus replaceable structure, seems premature when we don't know the parameters or even type of bombardment we'd be working with.

ncmncm 4y ago
Bombardment is with hot neutrons. Period.