|MadSci Network: Earth Sciences|
How do you turn uranium into power? When you heat something, down at the atomic level the heat energy makes the atoms move faster. How fast they move depends on how hot they are. When Uranium fissions, inside the fuel in a nuclear power plant, it emits energy in the form of radiation. That radiation doesn't travel far before it hit other atoms. When it hits, it will give up all or part of its energy to those other atoms. The atoms that are hit gain energy. They move faster. That faster movement means that their temperature has increased. With high levels of fissioning, the overall temperature of the nuclear fuel increases. The fuel is surrounded by water that is used as a coolant the same way water is used to cool a car's engine. Heat is transferred to the water making it boil into steam. The steam is used to drive a turbine. A turbine is just a high tech pinwheel. When the steam blows on it, it spins. It is connected to an electrical generator. When the generator turns, it literally "pumps" electricity through those wires that run to houses, stores, and schools. So the faster the Uranium fissions, the more heat it generates. The more heat, the more steam. The more steam, the more electrical power. To go back to the beginning, if you are interested in the details of how Uranium fission creates the energy to start the process of making electrical power, that is tied to how atoms are formed. The core or nucleus on an atom is formed by assembling neutrons and protons. When the atom is formed, energy called "Binding Energy" is given off. In other words, the atoms, once formed are reasonably stable. If we wanted to break them up, we would have to replace that Binding Energy by putting energy into the nucleus. But the larger atoms, because of the close grouping of positively charged protons in their nucleus that repel each other, are easier to break apart. The isotope of Uranium of atomic weight 235, it was found, can be broken up if it is hit with a neutron. When it breaks, it forms two other, smaller atoms, and these new atoms always have a higher Binding Energy. Because of their higher Binding Energy, the difference between the binding energy of the original Uranium atom and these two new atoms is emitted at the time the Uranium splits. And, that is the energy that causes the events mentioned above that leads to the generation of electrical power. MadSci note: an excellent site to visit for more information on fission is the following: http://www.fas.org/nuke/hew/Usa/Med/Discfiss.html
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