The Basics of Nuclear Energy — An Overview
Nuclear power uses the energy created by controlled nuclear reactions to produce electricity.
Fission
Nuclear Fission
Source: Atomicarchive.com at: http://www.atomicarchive.com/Fission/Fission1.shtml
The most commonly used nuclear reaction for power generation is nuclear fission. Nuclear fission is the splitting of an atom's nucleus into parts (lighter nuclei that are different from the parent and neutrons) by capturing a neutron. Nuclear fission produces heat (also called an exothermic reaction), because if you add all the masses together of the products of reaction you do not get the starting mass. That loss of mass is the heat and electromagnetic radiation produced during fission, and it produces large amounts of energy that can be utilized for power. Fission produces neutrons which can then be captured by other atoms to continue the reaction (chain reaction) with more neutrons being produce at each step. When a reaction reaches critical mass, the reaction becomes self sustaining. If too many neutrons are generated, the reaction can get out of control and an explosion can occur. To prevent this from occurring, control rods that absorb the extra neutrons are interspersed with the fuel rods. Uranium-235 is the most commonly used fuel for fission. Nuclear fission can produce 200 MeV of energy.
An Example of a Chain Reaction
Source: Atomicarchive.com at: http://www.atomicarchive.com/Fission/Fission1.shtml
Fusion
Nuclear Fusion
Source: Atomicarchive.com at: http://www.atomicarchive.com/Fusion/Fusion1.shtml
Nuclear fusion is another method to produce nuclear energy. Two light elements, like tritium and deuterium, are forced to fuse and form helium and a neutron. This is the same reaction that fuels the sun and produces the light and heat. Unlike fission, fusion produces less energy (~18 MeV), but the components are more abundant and cheaper than uranium.