Comment by westurner
5 days ago
To rephrase the question: what is the limit to the duration of sustained inertial confinement fusion plasma in the EAST, WEST, and ITER tokamaks, and why is the limit that amount of time?
Don't those materials melt if exposed to temperatures hotter than the sun for sufficient or excessive periods of time?
For what sustained plasma duration will EAST, WEST, and ITER need to be redesigned? 1 hour, 24 hours?
The magnets in the device make the plasma be in a doughnut like shape to prevent it from touching the rest and it has active cooling, the parts that are around the plasma are made out of tungsten to dissipate heat. The sustained plasma duration would have to be turned on for as long as a traditional power generation device like a fission reactor or an oil / coal power station.
EAST, WEST, URNER
[LLNL] "US scientists achieve net energy gain for second time in nuclear fusion reaction" (2023-08) > "Innovative target design leads to surprising discovery in laser-plasma acceleration" (2025-02) https://www.nature.com/articles/s41467-025-56248-4
Timeline of nuclear fusion: https://en.wikipedia.org/wiki/Timeline_of_nuclear_fusion
That energy gain was only in the plasma, not in the entire system.
The extremely low efficiency of the lasers used there for converting electrical energy into light energy (perhaps of the order of 1%) has not been considered in the computation of that "energy gain".
Many other hidden energy sinks have also not been considered, like the energy required to produce deuterium and tritium, or the efficiencies of capturing the thermal energy released by the reaction and of converting it into electrical energy.
It is likely that the energy gain in the plasma must be at least in the range 100 to 1000, in order to achieve an overall energy gain greater than 1.