How a nuclear fission reactor works
>>> The Proton-Proton Chain
>>> The Triple-Alpha Process
>>> Advanced Nuclear Burning Stages
>>> The Solar Neutrino "Problem"
The Proton-Proton Chain :
1H + 1H --> 2H + e+ + neutrino
2H + 1H --> 3He + gamma-ray
3He + 3He --> 4He + 2 1H
The individual nuclear reactions proceed rather slowly, and it is a very small fraction of nuclei in the core of the sun with enough energy to overcome the electrical repulsion.
The Triple-Alpha Process :
4He + 1H --> 5X
4He + 4He --> 8X
4He + 4He + 4He --> 12C
Advanced Nuclear Burning Stages :
nuclear burning stages are given below
>>>>Successive nuclear burning stages, involving more massive nuclei with higher charges, will require increasingly high temperatures to overcome the increased electrical repulsion.
>>>>The amount of energy released by each successive reaction stage decreases so that later nuclear burning stages become shorter and shorter.
>>>>Once fusion reactions have produced an iron core, further fusion reactions no longer produce energy, but absorb energy from the stellar core. As we shall see this may have a catastrophic effect on the star as it nears the end of its life.
12C + 4He --> 160 + gamma-ray
160 + 4He --> 20Ne + gamma-ray
12C + 12C --> 24Mg + gamma-ray
160 + 160 --> 32S + gamma-ray