It is not essential to know much about nuclear fusion at GCSE other than what the reactants and products are, and the fact that a LOT of energy is released as a result.


Hydrogen nuclei fuse together to form Helium nuclei, and the energy released is what makes the star shine. Many ‘main sequence’ stars will burn for millions of years until they run out of Hydrogen nuclei to fuse.


Step 1:



Two Hydrogen (Protium) nuclei fuse together to form a Deuterium nucleus, a proton turns into a neutron releasing a positron and a neutrino (energy)


Step 2:




A Hydrogen (Protium) nucleus fuses together with a Deuterium nucleus forming an isotope of Helium (Helium-3) and emission of a Gamma ray.


Step 3:



Two Helium-3 isotope nuclei collide to form a Helium-4 isotope, releasing two Hydrogen (Protium) nuclei.