Question by s m: Why does Fusion create more energy than fission?
Why does Fusion create more energy than fission?
Best answer:
Answer by Matus1976
The answer lies in the difference in energy of the nucleus of a small atom which would be fused, and a large atom which would be split. When two small elements are brought to together, each individual nucleon (proton or neutron) are much closer to the nucleons they fuse to. Since the strong nuclear force which holds nucleons together extends over a very short range, In a large element like Uranium (235 nucleons) any typical nucleon might only be bound to a few neighboring nucleons, while in a small element virtually all the nucleons are bound by the strong nuclear force to another nucleon. So the total amount of ‘binding’ energy in a larger atomic nucleus will be smaller than the binding energy in a small nucleus. As you bring more small nucleus atoms together the binding energy increases, but as the size of the atom increases more of the nucleons become further apart from the rest in the nucleus, and eventually the electrostatic repulsion force of the protons exceeds the strong nuclear attractive force and the binding energy levels off. As the atom gets larger, they become unstable and the binding energy decreases.
So when you fission a large element into two smaller, but still large elements, the binding energy of any particular nucleon is lower, and the number of nucleons effected with respect to the total number in the system is smaller. When you fuse smaller atoms, all of the nucleons feel the strong nuclear force to each, and they are all much closer to each other, so the binding energy is much higher. A shorter quick way to think of it might be the ‘binding density’ (binding energy per nucleon) in a large fissionable atom is much lower than the ‘binding density’ in a small fissionable atom.
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