they say its not viable because it requires electricity to generate the electromagnetic fields that are used to contain and stabilize the plasma.  in order to overcome this or reduce the energy required they need superconductors that work at normal tempatures. and they just dont have the elements, or cant synthesize them or they refuse to tell people that they've solved this problem and can generate "free" energy. or at least, get fission viable enough to keep the damn thing running. but as of right now, they turn the thing on for extremely brief periods of time just to test it. but without more energy efficient electromagnetic fields its just not worth it.. way too much energy thats generated goes right back into stabilizing the plasma.
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