Nuclear Power

Nuclear Power

Producing energy from a nuclear power plant is very complicated. The process of

nuclear energy involves the fission of atoms, the release of energy from fission

as heat, and the transfer of heat to electricity in power plants.

The process of splitting the atom is called nuclear fission. Fission can take

place in many different kinds of atoms. This explanation uses Uranium - 235,

the atom most commonly used in nuclear reactors. The Uranium atom has many

protons, thus making it unstable. Since the nucleus of the atom is so unstable

it wants to split itself apart, causing a spontaneous fission. When the nuclei

of a Uranium atom splits apart, it splits into two atoms. Commonly the nucleus

splits into Barium and Krypton; however, it can split into any two atoms as long

as the number of protons equals the original amount of the protons found in the

Uranium. In addition, a mass amount of energy is released along with two or

three neutrons. It is these neutrons that can begin a chain reaction, each

neutron that is given off could collide with another Uranium atom splitting it

apart. Each of these fissioning atoms releases a very large amount of energy,

and some more neutrons.

This process continues causing a chain reaction withut any outside assistance,

and the Uranium has "gone critical"(Martindale, 794-195). This chain reaction

is the basis for how nuclear power is made.

The amount of the energy that is given off in nuclear fission is astronomical.

To equal the amount of energy given off when splitting some uranium the size of

a golf ball, one would have to burn approximately twenty-five train cars full of

coal. Presently, the planet contains twenty-five times more nuclear fuel

compared to fossil fuel. On average, an atomic power plant can produce half a

million kilowatts of power. As a comparison, a hair dryer takes about one

kilowatt (Jenny, 1-2).

The producing of energy from nuclear fission is very similar to using a very

common fossil fuel boiler. The difference lies in the reactor, where the heat

is generated by fissioning material. The most common of reactors is the

pressurized water reactor; however, there are many other types.

The pressurized water reactor is the most common reactor in the United States.

The reactor of a nuclear power plant is where the fissioning takes place. The

Uranium is contained in fuel rods, each rod is sealed so no contamination occurs.

Many of these rods are then contained in a fuel assembly. All the fuel

assemblies are separated by control rods. The control rods limit the amount of

fission taking place by the use of Boron, an element that absorbs neutrons. If

the control rod is inserted, it collects the neutrons from the fissioning atoms,

which slows down or stops fission taking place in the reactor. There commonly

are 300 to 600 fuel assemblies in one reactor (Michio, 31). Surrounding all of

the fuel assemblies is a moderator, water in most cases. The moderator is a

substance that is used to slow down the neutrons. The slower the neutrons

travel, the more likely they will strike the nucleus of an atom. The process

begins when a spontaneous fission takes place and starts the chain reaction. The

control rods are the inserted to keep the rate of fission constant, this is

called "going critical". As the fission takes place in the fuel assemblies, the

kinetic energy (heat) given off is absorbed by the water. The water is under

pressure so it will never boil. The water becomes super heated, sometimes above

300Ð'Ñ" C, and is then pumped into a heat exchanger. The heat exchanger runs water,

at normal pressure, through pipes in the super heated water, boiling the water

at normal pressure vigorously. That boiling water quickly turns to steam which

is then used to turn massive generators. The generators then turn the kinetic

energy into electricity (Weiss, 26). The steam then is cooled down and returned

to the heat exchanger so it will boil again. If there is no need to use the

water again, it is pumped into a nearby lake or river. In turn, if more water

is needed, it is pumped from a nearby lake or river. If the water in the

reactor becomes too hot, it is vented into a cooling