3 ms·

Summary in text for those of us that cannot watch a video at present?

majjam 9y ago
tl;dw: the best model is the tokamak, new magnets mean that they can be much smaller (and cheaper) than expected. This is awkward for existing projects (iter).
- markvdb 9y ago
  Plus: * Stellarators like https://en.wikipedia.org/wiki/Wendelstein_7-X https://en.wikipedia.org/wiki/Wendelstein_7-X are very interesting academically, and the only alternative approaching net energy positive fusion within an order of magnitude. * The shrinking of the process thanks to HTS magnet technology brings net energy positive fusion within reach of national governments or soon even major institutions. He was promoting a compact MIT tokamak design called SPARC, a derivative of ARC described below: http://news.mit.edu/2015/small-modular-efficient-fusion-plant-0810 http://news.mit.edu/2015/small-modular-efficient-fusion-plan...
Geee 9y ago
Tokamak's output is relative to its size and strength of the magnetic field. Using new off-the-shelf high-temperature superconductors you make make ITER on your kitchen table.
yk 9y ago
Short answer, MIT discovered unobtanium and now fusion looks pretty good. Longer answer, the crucial part in a fusion reactor is the magnetic confinement and with the field strength conventional superconductors can manage you need a large reactor. In the last 20 years two things happened, first high temperature super conduction was discovered and someone figured out how to build a compound material from them and stainless steel. The high temperature super conductors solve the problem that there is a critical magnetic field strength and the stainless steel solves the problem that the material has ugly mechanical properties. With that you can use much higher field strength in your fusion reactor and that means much smaller reactor and that means much cheaper experiments. (In another talk the speaker claimed the scale of the experiments drops from large experiment for the entire international community to large experiment for MIT.) Last time I looked at that project, it looked that the MIT fusion group is competitive with ITER, and it should be mentioned that even if the path forward is high temperature super conductors, then ITER was still the right bet 15 years ago. The thing is 15 years ago you could not bet on everything magically working out and the entire ITER concept is guaranteed to work. The international community did decide that fusion is interesting enough even if the safe path forward is really really expensive.

tl;dw: the best model is the tokamak, new magnets mean that they can be much smaller (and cheaper) than expected. This is awkward for existing projects (iter).

markvdb 9y ago
Plus: * Stellarators like https://en.wikipedia.org/wiki/Wendelstein_7-X https://en.wikipedia.org/wiki/Wendelstein_7-X are very interesting academically, and the only alternative approaching net energy positive fusion within an order of magnitude. * The shrinking of the process thanks to HTS magnet technology brings net energy positive fusion within reach of national governments or soon even major institutions. He was promoting a compact MIT tokamak design called SPARC, a derivative of ARC described below: http://news.mit.edu/2015/small-modular-efficient-fusion-plant-0810 http://news.mit.edu/2015/small-modular-efficient-fusion-plan...

Geee 9y ago

Tokamak's output is relative to its size and strength of the magnetic field. Using new off-the-shelf high-temperature superconductors you make make ITER on your kitchen table.

yk 9y ago

Short answer, MIT discovered unobtanium and now fusion looks pretty good. Longer answer, the crucial part in a fusion reactor is the magnetic confinement and with the field strength conventional superconductors can manage you need a large reactor. In the last 20 years two things happened, first high temperature super conduction was discovered and someone figured out how to build a compound material from them and stainless steel. The high temperature super conductors solve the problem that there is a critical magnetic field strength and the stainless steel solves the problem that the material has ugly mechanical properties. With that you can use much higher field strength in your fusion reactor and that means much smaller reactor and that means much cheaper experiments. (In another talk the speaker claimed the scale of the experiments drops from large experiment for the entire international community to large experiment for MIT.) Last time I looked at that project, it looked that the MIT fusion group is competitive with ITER, and it should be mentioned that even if the path forward is high temperature super conductors, then ITER was still the right bet 15 years ago. The thing is 15 years ago you could not bet on everything magically working out and the entire ITER concept is guaranteed to work. The international community did decide that fusion is interesting enough even if the safe path forward is really really expensive.