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I think fission to fusion is more like steam engine to jet engine. Fission can happen by _accident_ if you have the right materials at energy levels of just dro
by ubercore 6y ago
I think fission to fusion is more like steam engine to jet engine. Fission can happen by _accident_ if you have the right materials at energy levels of just dropping something on something else [0].
Starting fusion isn't easy, but as I understand it, that's not even the hard part. Containment is the big deal, because of the energy needed.
[0] https://en.wikipedia.org/wiki/Demon_core https://en.wikipedia.org/wiki/Demon_core
- fastball 6y agoIsn't the Sun fusion happening by accident?
- JoshuaDavid 6y agoSure, and solar power is cheap fusion energy. Getting fusion energy without gravitational confinement is the tricky bit.
- semi-extrinsic 6y agoYeah, but the Sun only works because of its unfathomably massive size, compared to anything we can do on Earth. If you take 800 cubic meters of plasma from the core of the Sun, about the same volume as ITER, it only produces 216 kW - comparable to the engine in your car. And in that volume, you will have an average rate of 1500 hydrogen fusion reactions per second. Compared to ITER, this is something like twelve orders of magnitude slower. That is why ITER needs to go to much higher temperatures than the sun.
- pfdietz 6y agoYou have made an error somewhere. 1500 fusion reactions per second is maybe 10^10 eV per second, which would be around a nanowatt.
- semi-extrinsic 6y agoYeah, you are right there is a mistake. I made a typo in Avogadro's number. Sorry about that! The power density is correct, but the number of reactions is too low by a factor of 10^10...
- jabl 6y agoThere's a saying that fission is like playing a mini-golf course where you have a flat surface peppered with holes, and every time you hit a hole you get ~2 new balls. Fusion is like a mini-golf course which is a volcano mountain with a tiny hole on the top.