A gif representing nuclear fusion and how it creates energy.
For those who don’t understand the GIF. It illustrates the Deuterium-Tritium fusion; a deuterium and tritium combine to form a helium-4. Most of the energy released is in the form of the high-energy neutron.
Nuclear fusion has the potential to generate power without the radioactive waste of nuclear fission (energy from splitting heavy atoms into smaller atoms), but that depends on which atoms you decide to fuse. Hydrogen has three naturally occurring isotopes, sometimes denoted ¹H, ²H, and ³H. Deuterium (²H) - Tritium (³H) fusion (pictured above) appears to be the best and most effective way to produce energy. Atoms that have the same number of protons, but different numbers of neutrons are called isotopes (adding a proton makes a new element, but adding a neutron makes an isotope of the same atom).
The three most stable isotopes of hydrogen: protium (no neutrons, just one proton, hence the name), deuterium (deuterium comes from the Greek word deuteros, which means “second”, this is in reference two the two particles, a proton and a neutron), and tritium (the name of this comes from the Greek word “tritos” meaning “third”, because guess what, it contains one proton and two neutrons). Here’s a diagram
Deuterium is abundant, it can be extracted from seawater, but tritium is a radioactive isotope and must be either derived(bred) from lithium or obtained in the operation of the deuterium cycle. Tritium is also produced naturally in the upper atmosphere when cosmic rays strike nitrogen molecules in the air, but that’s extremely rare. It’s also a by product in reactors producing electricity (Fukushima Daiichi Nuclear Power Plant). Tritium is a low energy beta emitter (unable to penetrate the outer dead layer of human skin), it has a relatively long half life and short biological half life. It is not dangerous externally, however emissions from inhaled or ingested beta particle emitters pose a significant health risk.
During fusion (energy from combining light elements to form heavier ones), two atomic nuclei of the hydrogen isotopes deuterium and tritium must be brought so close together that they fuse in spite of the strongly repulsive electrostatic forces between the positively charged nuclei. So, in order to accomplish nuclear fusion, the two nuclei must first overcome the electric repulsion (coulomb barrier ) to get close enough for the attractive nuclear strong force (force that binds protons and neutrons together in atomic nuclei) to take over to fuse the particles. The D-T reaction is the easiest to bring about, it has the lowest energy requirement compared to energy release. The reaction products are helium-4 (the helium isotope) – also called the alpha particle, which carries 1/5 (3.5 MeV) of the total fusion energy in the form of kinetic energy, and a neutron, which carries 4/5 (14.1 MeV). Don’t be alarmed by the alpha particle, the particles are not dangerous in themselves, it is only because of the high speeds at which they are ejected from the nuclei that make them dangerous, but unlike beta or gamma radiation, they are stopped by a piece of paper.
Some fundamentals of fusion.