So helium is a limited resource. Okay gotcha. So why not take two hydrogen atoms. Take their protons and neutrons. And just fucking start squeezing them together until you get helium?
And I don’t mean in the same way you get H2. Those are still separate from each other.
The forces within an atom are very strong and complex. We can create fission chain reactions in some very radioactive elements, and we can fuse some small elements, but the amounts of such reactions we can produce is pretty restricted. Beside, a particule that exits an atom will leave at a high speed, and it’s impossible to reliably know where it goes because of the rules of quantum physics, so it’s not like you can just take a proton and leave it in a box to reuse later. What we can use is the energy produced by the fission, and that’s what nuclear plants do.