6 ms·

Timeline (in case you want to skip over some parts): 00:01:00 - introducing Dennis Whyte, MIT department head for nuclear science 00:04:24 - presentation star

Timeline (in case you want to skip over some parts): 00:01:00 - introducing Dennis Whyte, MIT department head for nuclear science 00:04:24 - presentation starts 00:06:00 - identifies breakthrough with REBCO magnets 00:07:25 - explains deuterium-tritium fusion 00:12:30 - basic metrics for reactor performance 00:17:15 - energy output of other previous fusion experiments 00:19:00 - examines ITER and the problems of its approach 00:22:00 - problems solved by high energy magnetic fields 00:28:15 - full scale reactor concept, teardown of REBCO magnets 00:37:00 - design limits and margins 00:39:00 - fixes plasma instabilities found in weaker magnetic chambers 00:40:00 - maintainability, lifespan, component replacement 00:45:00 - solution to neutron damage and energy capture 00:50:30 - cost and profitability 00:54:00 - full graph of field strength vs reactor scale (and thus funding requirements) 01:01:50 - Q&A 01:30:00 - question about the biggest risks Also a more recent video, with more numbers and even more confidence than the first: https://www.youtube.com/watch?v=rY6U4wB-oYM https://www.youtube.com/watch?v=rY6U4wB-oYM

Robotbeat 6y ago
I think they're using Yttrium (i.e. YBCO), right? It's hard to find that info.
- hyperion2010 6y ago
  Buried in the wiki page for YBCO is a note that REBCO is a synonym of sorts. The superconducting tapes that are discussed in the talk thus would seem to be YBCO.
  - Robotbeat 6y ago
    Yes. Re stands for "rare earth," and yttrium is probably the most common one used for ReBCO, but lanthanum is also used.
- dbetteridge 6y ago
  https://nationalmaglab.org/magnet-development/magnet-science-technology/publications-mst/highlights-mst/high-temperature-superconducting-rebco-tapes https://nationalmaglab.org/magnet-development/magnet-science... Looks like they 'only' need to be at 4.2Kelvin as well to operate, which is a definite improvement
  - MertsA 6y ago
    They don't need to be that cold to start superconducting, 4.2K is just the temperature you could expect with liquid helium cooling. It would actually be superconducting with liquid nitrogen but the reason why you would still want to go colder is because superconductors have a maximum magnetic flux that they can sustain while still being superconducting. The current travelling through a superconductor itself also contributes to the magnetic flux so even though it's superconducting there's still a limit as to how much current you can pass through a conductor and how high of a magnetic field you can create. This limit is dependent on temperature though, so you definitely want to use liquid helium so you can create a much stronger magnetic field.
    - Robotbeat 6y ago
      Right. To expand: Maybe someday we can use liquid hydrogen or nitrogen (or even water, depending on progress with hydride superconductors) for these reactors, but a big reason they’re able to make this more compact reactor work is the much higher critical currents/fields that these high temperature superconductors can handle when cooled far below their critical temperature. See: https://fs.magnet.fsu.edu/~lee/plot/plot.htm https://fs.magnet.fsu.edu/~lee/plot/plot.htm
joeraut 6y ago
The hero we don't deserve.

Robotbeat 6y ago

I think they're using Yttrium (i.e. YBCO), right? It's hard to find that info.

hyperion2010 6y ago
Buried in the wiki page for YBCO is a note that REBCO is a synonym of sorts. The superconducting tapes that are discussed in the talk thus would seem to be YBCO.
- Robotbeat 6y ago
  Yes. Re stands for "rare earth," and yttrium is probably the most common one used for ReBCO, but lanthanum is also used.
dbetteridge 6y ago
https://nationalmaglab.org/magnet-development/magnet-science-technology/publications-mst/highlights-mst/high-temperature-superconducting-rebco-tapes https://nationalmaglab.org/magnet-development/magnet-science... Looks like they 'only' need to be at 4.2Kelvin as well to operate, which is a definite improvement
- MertsA 6y ago
  They don't need to be that cold to start superconducting, 4.2K is just the temperature you could expect with liquid helium cooling. It would actually be superconducting with liquid nitrogen but the reason why you would still want to go colder is because superconductors have a maximum magnetic flux that they can sustain while still being superconducting. The current travelling through a superconductor itself also contributes to the magnetic flux so even though it's superconducting there's still a limit as to how much current you can pass through a conductor and how high of a magnetic field you can create. This limit is dependent on temperature though, so you definitely want to use liquid helium so you can create a much stronger magnetic field.
  - Robotbeat 6y ago
    Right. To expand: Maybe someday we can use liquid hydrogen or nitrogen (or even water, depending on progress with hydride superconductors) for these reactors, but a big reason they’re able to make this more compact reactor work is the much higher critical currents/fields that these high temperature superconductors can handle when cooled far below their critical temperature. See: https://fs.magnet.fsu.edu/~lee/plot/plot.htm https://fs.magnet.fsu.edu/~lee/plot/plot.htm

joeraut 6y ago

The hero we don't deserve.