Theoretically, two lone nuclear reactors running on small pellets could power the entire planet, safely and cleanly. That's the promise of nuclear fusion. So, why are we still relying on fossil fuels? What's stopping us from building these reactors everywhere? After all, scientists have been working on nuclear fusion technology since the 1950s and have always been optimistic that the final breakthrough is not far away. Yet, milestones have fallen time and again and now the running joke is that a practical nuclear fusion power plant could still…
