In controllable nuclear fusion facilities, there is an extremely important concept: the Q value.
It is the ratio of the output energy to the input energy of a nuclear fusion reactor.
Assuming 1 MJ of energy is input to start and maintain the fusion, but the nuclear fusion reactor can only produce 0.8 MJ of energy, then the Q value is 0.8, which is less than one, meaning it's running at a loss; this set of reactor technology clearly lacks practicality.
As early as the human era, people had already mastered controllable nuclear fusion technology, and had even achieved a Q value of around 5.
However, this technology still faced enormous challenges.
Firstly, the ignition time was insufficient. Such a device could usually only operate for a few minutes before shutting down, unable to sustain itself for long periods.
Secondly, a Q value of 5 was still far too low.
