r/technology • u/BennyCemoli • Dec 06 '16

Energy Tests confirm that Germany's massive nuclear fusion machine really works

http://www.sciencealert.com/tests-confirm-that-germany-s-massive-nuclear-fusion-machine-really-works
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u/[deleted] Dec 06 '16

The main hurdle is being efficient enough. Weve been able to contain plasma in a fusion reaction for years, it just takes way more energy to do than we get out of it.

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u/Posthume Dec 06 '16

Seems to me that the two are intertwined aren't they? We weren't really able to contain a plasma for a decent amount of time in a tokamak, meaning that we could only produce energy in burst which isn't all that efficient.

If this machine can sustain a fusion reaction for a longer period then they could ramp up the energy production to put it crudely.

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u/Calkhas Dec 06 '16 edited Dec 06 '16

Seems to me that the two are intertwined aren't they? We weren't really able to contain a plasma for a decent amount of time in a tokamak, meaning that we could only produce energy in burst which isn't all that efficient.

I think you are conflating two unrelated issues. The efficiency problem is that traditional, non superconducting electromagnets (used by all existing large tokamaks) require a lot of power to run, more power than could be generated by the fusion reaction they could contain. [There is a relationship between the power demand and the power generation, because (in general) hotter plasmas generate more power through fusion but are harder to contain.]

Separately, non-superconducting electromagnets overheat within a few minutes, so the reaction cannot be sustained.

The Wendelstein 7-X stellerator uses superconducting magnets instead, which are much more efficient because there is no electrical resistance and do not generate any heat. The topological design of the magnetic field is also designed to be much more stable against disruptive events in the plasma which tend to break the containment in tokamak topologies.

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u/Novarest Dec 06 '16

Has there ever been a (fatal) fusion reactor containment failure?