Nuclear energy can be produced either by fission or fusion. Nuclear fission is the process of splitting the nucleus of an atom. We do this on a commercial and military basis to use the energy released from the binding energy of a large atom. The nucleus is split into two or more parts by hitting it with a small particle, almost always a neutron (a proton would be repelled from the positive nucleus and an electron would have too little energy).
The isotope most commonly used to produce energy from nuclear fission is Uranium 235
If a neutron strikes the uranium nucleus with the “right” amount of kinetic energy the neutron enters the nucleus and destabilises it. The nucleus then splits into two large parts and releases a large amount of energy.
Nuclear fusion can produce a large amount of nuclear energy but it is hard to control. Nuclear fusion is a process where two atoms (or rather the nucleus of two atoms) are fused together. In practical terms the atoms have to be small, usually atoms of an isotope of hydrogen, deuterium which is fused into helium. Larger atoms up to the size of iron (nucleon number 56) are more stable than smaller atoms and therefore energy is released when they fuse together. The video aims to explain the possible processes, why they produce energy and the nature of the international projects aiming to harness nuclear fusion for electricity production.