How Do They Make Electricity at Nuclear Power Plants?

Nuclear Energy

Nuclear energy is energy produced by a controlled chain reaction. This chain reaction is produced from the fission of very heavy nuclei that are capable of nuclear fission. Uranium 235, a common, fissile reactor element, is an example for explaining the process of nuclear fission. First, neutrons are fired at the nucleus of the uranium 235 atom. When the neutron hits the nucleus of the atom, it causes the nucleus to quickly turn to uranium 236 (the number is representative of the number of neutrons), then quickly split into two lighter nuclei. This fission of the nucleus also produces more leftover neutrons, which then go on to hit more fissile nuclei. Once they hit the nuclei, the process repeats, if the right conditions are met (meaning enough luck is involved). This process releases enormous amount of kinetic energy, which is the energy produced in the reactor. However, too much energy cannot be produced all at the same time.

Controlling the Nuclear Fission

If the huge amounts of energy from nuclear fission sounds dangerous, it is. In fact, its so dangerous that it can level most of a city and turn desert into glass. That's right, an uncontrolled nuclear reaction is a nuclear bomb. So, a nuclear reactor must have a way of controlling the highly energetic fission reaction. This method of control is called a nuclear poison. In a nuclear reactor, it is concentrated in the control rods of the reactor, which are placed in varying proximity to the fissile material. These control rods can be placed in closer proximity to the fissile material to reduce the amount of nuclear fission or removed to increase the amount of fission, depending on the output of the reactor. An additional benefit of these control rods is that they can also be neutron moderators. This means that they slow neutrons to the point that the neutrons release heat energy from their loss of energy, which adds to the energy output of the reactor without letting the fission go out of control.

The Production of Electricity

Nuclear reactors produce large amounts of heat (even though they are largely cooled by different kinds of coolant systems). The heat produced by a nuclear reactor can be harnessed using flowing water. The fission heats the water, which then goes on to create steam to turn turbines and generators, creating electricity that can be fed into a grid and to consumers. The coolant in many nuclear reactors is simply the flowing water that passes through the reaction chamber and carries the produced heat to a heating coil, which then boils water, creating steam. As a final note, nuclear reactors produce nuclear waste as their only environmentally hazardous byproduct. This nuclear waste must be stored underground in a place where it can rest undisturbed for thousands of years.

Resources

• Encarta: Nuclear Energy