Essay/Term paper: Nuclear power

Essay, term paper, research paper:  College Papers

Most of the world"s electricity is generated by either thermal or
hydroelectric power plants. Thermal power plants use fuel to boil water
which makes steam. The steam turns turbines that generate electricity.
Hydroelectric power plants use the great force of rushing water from a
dam or a waterfall to turn the turbines.
The majority of thermal power plants burn fossil fuels because thermal
power plants are cheaper to maintain and have to meet less of the
governments requirements compared to nuclear power plants. Fossil fuels
are coal and oil. The downfall of using fossil fuels is that they are
limited. Fossil fuels are developed from the remains of plants and
animals that died millions of years ago. Burning fossil fuels has other
downfalls, too. All the burning that is required to turn the turbines
releases much sulfur, nitrogen gases, and other pollutants into the
atmosphere.
The cleanest, cheapest, and least polluting power plant of the two types
is the hydroelectric power plant. The main reason most countries use
thermal versus the hydroelectric is because their countries don"t have
enough concentrated water to create enough energy to generate
electricity. (World Book vol. 14, 586)
Nuclear power plants generate only about eleven percent of the world"s
electricity. There are around 316 nuclear power plants in the world
that create 213,000 megawatts of electricity. (INFOPEDIA)
Radioactive, or nuclear, waste is the by-product of nuclear fission.
Fission occurs when atoms" nucleus" split and cause a nuclear reaction.
(General Information) When a free neutron splits a nucleus, energy is
released along with free neutrons, fission fragments that give off beta
rays, and gamma rays. A free neutron from the nucleus that just split
splits another nucleus. This process continues on and is called a chain
reaction. (World Book vol. 14, 588)
The fission process is used to create heat, which boils water inside the
nuclear reactor. The steam that boiling the water makes is used to turn
turbines, which in turn, generate electricity. Fission happens inside a
carefully monitored nuclear reactor, when being used in a nuclear power
plant. The fission process that nuclear power plants use spends
approximately 30,000 tons of highly radioactive waste a year. (General
Information)
In a nuclear power plant, Uranium is used as fuel to boil the water for
the steam that makes the turbines turn. So, uranium is, in a sense, the
coal of a coal-fired power plant.
When fueling nuclear power plants, the uranium arrives as
uranium-enriched pellets. These pellets are an equivalent to one ton of
coal. The pellets are sealed in tubes that are made of a strong heat-
and corrosion-resistant metal alloy. This metal alloy will protect
people and the environment from the high levels of radiation that the
uranium is giving off.
The tubes are bundled together to make a fuel assembly. The assemblies
are put inside the reactor to create heat that will boil the water. The
fuel assemblies are used until they are depleted. A fuel assembly is
depleted when it no longer gives off enough energy to turn the turbines.

Once every year, one third of the nuclear fuel in a reactor is replaced
with fresh fuel. The used-up fuel is called spent fuel. Spent fuel is
highly radioactive and is the primary form of high-level nuclear waste.
(General Information)
High-level radioactive waste is the by-product of commercial nuclear
power plants generating electricity, and from nuclear materials
production at defense facilities. This high-level waste must be
isolated in a safe place for thousands of years so its radioactivity can
die down and not be harmful to people and the environment.
The name of the safe place that the Department of Energy is trying to
make is called a repository. But until a repository is made, spent fuel
and high-level waste is being stored in temporary storage facilities
called dry casks and cooling pools. By the end of the year 2000, there
will be more than 40,000 metric tons of high-level waste in casks and
storage pools. There will also be more than 8,000 metric tons of
high-level waste from defense programs. The high-level waste from
defense programs is currently being stored in Idaho, South Carolina, and
Washington. (General Information)
Reprocessing is the chemical process by which uranium and plutonium are
recovered from spent fuel. This means that it is the recycling process
of high-level waste. The reason private industries aren"t reprocessing
their high-level waste is because reprocessing costs more than mining
and making new fuel. Several countries that actually care about their
environment reprocess their high-level waste. (General Information)
Dry casks and cooling pools are being used to store spent fuel in power
plants everywhere. (Shulman, 14) Dry casks and cooling pools are only
meant to be temporary storage facilities until a permanent repository is
made. The need for a permanent disposal for high-level radioactive
waste is becoming more urgent every year because the dry casks and
cooling pools at nuclear power plants are filling up.
A dry cask is a concrete of steel container that protects the outside
world from its radioactive innards. A cooling pools is a pools of water
that the spent fuel is put into. The water is a radioactive shield and
coolant. (General Information)
The cooling pools were supposed to contain no more than 400 fuel
assemblies, approximately 80,000 rods. The pools contain over four
times as much of the spent fuel that they"re supposed to. Nearly all of
the nations older power plants are in this state of overload.
In the late 1980"s, government industry researchers became concerned
that if the rods were too closely stored in the pools, a nuclear
reaction would occur. When researched further, the chain reaction
theory became very remote. News of this resulted in even more densely
packed cooling pools. (Shulman, 14)
The cooling pools are a type of concrete warehouse. Inside the
warehouses are steel caskets containing the spent fuel rods and cooling
pools. Scientists say that the cooling pool prevents the spent fuel to
explode, but the extreme weight of the fuel inside the warehouses might
cause the structures to rupture, especially in the case of an
earthquake. (Shulman, 15)
A repository is a storage facility that stores high-level nuclear waste
deep underground so the waste can not harm or effect people or the
environment. (DOE"s Yucca Mountain Studies) With the technology that
we [humankind] have toady. Scientists believe it to be possible to make
a repository somewhere. The guidelines of a repository are mainly if
the geologic location will work out (i.e. will an earthquake be able to
rupture it, will water be able to corrode the repositories outer wall.).

To make sure that the repository would be able to stay unscathed for
thousands of years, scientists in all areas of science are making
predictions of what could happen over the time period.
According to U.S. Environmental Protection Agency (EPA) standards, a
repository may pose no greater threat than unmined uranium from which
the high-level waste was produced. (General Information)
The repository the DOE is wanting to make has to be proven that it will
still be isolated underground in 10,000. After this extensive time, the
high-level waste should no longer be radioactive enough to harm the
public health. (General Information)
A rem is a unit scientist use to measure radiation exposure. Over a
persons lifetime, they usually receive 7-14 rems of natural sources of
radiation, such as cosmic rays and ultraviolet rays from the sun. On a
single exposure of 5-75 rems, there are few to no noticeable symptoms.
For someone to receive 75-200 rems of exposure, vomiting, fatigue, and
loss of appetite would occur. Recovery would take a few weeks. If
someone were to be exposed to more than 300 rems, severe changes in
blood cells and hemorrhage takes place. If someone were to receive more
than 600 rems, symptoms would be hairloss, loss in your bodies ability
to fight infection and usually results in death. (World Book vol. 16,
79)
As you can see, the effects of radiation sickness is not too pleasant.
The main reason for building a repository is to keep people and the
environment safe from deadly radiation.
Bibliography


"DOE"s Yucca Mountain Studies." A repository is an enormous
challenge. URL: http://www.ymp.gov/faq/facts/geninfo/y0343p.htm (4 Feb.
1997)

"General Information." What is nuclear fuel and waste? URL:
http://www.ymp.gov/faq/facts/geninfo/Y338P.HTM (4 Feb. 1997)

INFOPEDIA. Vers. 1.5. Computer software. Future Vision Multimedia,
1995. IBM Windows 3.1, 30KB, CD-ROM.

Shulman, Seth. "Waiting Game for Nuclear Waste." Technology Review
Aug. - Sept. 1992: 14-15.

World Book. 22 Volumes. Vol.14 and 16. Chicago: World Book, Inc.,
1988