Реферат на тему The Negative Effects Of Nuclear Energy Essay
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The Negative Effects Of Nuclear Energy Essay, Research Paper
In 1950, the first commercial nuclear power
plants were constructed. The public was promised
a non-polluting and resourceful type of energy, but
how safe was, and is, nuclear energy? Although
there are less than 500 licensed nuclear power
plants in the world, many nuclear accidents have
already been endangering civilian lives. More
serious accidents are not just likely, but inevitable
(Fairchild 29). Nuclear energy may appear to be
the ideal source of energy for the future: however,
there are many negative effects of nuclear energy
that can lead to very dangerous situations.
Energy has always been among the basic human
concerns, along with food and shelter. It takes
part in all activities, from walking to the operation
of even the most complicated equipment. Mankind
has been faced with the challenge of meeting its
energy needs without risking human health and the
environment.
The many types of energy are mechanical, thermal,
chemical, electrical, radiant, and atomic (Microsoft
Encarta). In 1987, oil supplied 32% of the energy
worldwide. Coal was next in line with 26%, then
natural gas with 17%, biomass 15%, and nuclear
energy with only 4% (Galperin 19). With the main
sources of our energy running low, nations look to
new sources to provide our society with power.
Nuclear energy, the newest type of energy, was
researched to see if it would be the most
promising type of energy for the future.
Surprisingly, nuclear energy was discovered by
accident. In 1896, the French scientist, Antoine
Henri Becquerel, conducted an experiment with
uranium salts and found that these salts gave off
their own light when exposed to sunlight. Marie
and Pierre Curie were fascinated by the
possibilities of Becquerel?s rays. The Curies
discovered exactly what the rays were and then
named the phenomenon radioactivity (Halacy 6).
During World War II, many scientists from around
the world came to the United States to work on
nuclear reactors and weapons. With much
success, they continued after World War II and
concentrated more on nuclear energy. The
scientists instantly saw that nuclear energy would
be a great source of power because of the amount
of power it released. Splitting an amount of
uranium equal to one penny would produce as
much energy as seven and a half tons of coal
(Lilienthal 85).
A nuclear power plant is where energy is formed
when nuclear fission or fusion takes place. So far,
however, only the power of fission has been
controlled and used for energy. There are many
parts of the nuclear power plant, including the
reactor, generator, control room, cooling systems,
and the electrical, air, and water lines. The heart of
the nuclear power plant is its reactor core, which
contains a few hundred fuel assemblies. The
reactor core is encased in a pressured steel tank
with walls several inches thick. In most reactors,
this vessel is enclosed in a containment structure.
This is a steel-reinforced concrete dome that is
about three feet thick and serves as the outermost
barrier between the plant and the environment
around it. This helps prevent radiation from
escaping the plant (Galperin 42).
There are many different types of nuclear reactors,
but all the power plants in the United States and
more than three-quarters of those worldwide are
light-water reactors. There are two types of
light-water reactors, which are boiling-water and
pressurized-water reactors. Both types use
ordinary water as coolant and require enriched
uranium (Microsoft Encarta).
In boiling-water reactors, cooling water surrounds
fuel assemblies. The heat of nuclear fission makes
the water boil and the steam produced is carried
away from the core to the turbines. Once its work
is done, the steam is condensed to water and it
returns to the reactor (Galperin 44).
The pressurized-water reactor is more commonly
used than the boiling-water reactor. This reactor
seals the cooling water in a closed loop and adds
a heat-exchange system. Water in the reactor core
gets hot, but it does not turn to steam. The hot
water is piped through a steam generator and
converts a secondary water supply into steam to
power the turbine. The two water supplies do not
mix (Galperin 45).
A gas-cooled reactor is similar to a
pressurized-water reactor. The only main
difference is that helium or carbon dioxide gas
replaces the water in the primary loop. These
reactors cost more to operate and to build, but are
more energy efficient (Galperin 46).
The last main type of reactor is a breeder-reactor.
This is very different then other reactors because it
produces more fissionable material then it
consumes. A breeder reactor fuels with a
combination of plutonium and uranium. A breeder
reactor would be extremely useful if uranium was
scarce. It takes about 10 to 60 years to use up the
fuel from just one cycle (Galperin 46).
Radiation is very strong in the nuclear waste of
power plants. Nuclear waste exists in several
forms. One form is called high-level waste, and the
other is called low-level waste. High-level waste is
mostly from the used fuel rods and other materials
exposed to as much radiation as they are.
High-level wastes can let out very large amounts
of radiation for thousands of years. There is no
place to store this waste that is safe, and it will
always be radioactive. But for now, they are
stored in the ground. Other proposed storing
solutions are sending it to space, burying it in the
core of the earth, burying it in the ocean, or
burying it under the Antarctic ice. Even these ideas
have the potential of severely damaging the earth.
An example of low-level waste is the waste left in
the reactor water. This waste is less radioactive,
but is still very dangerous (Galperin 65).
Two engineers in Connecticut have, not too long
ago, caught the Nuclear Regulatory Commission
(NRC) in a dangerous game of disobeying the
rules. The NRC has been regularly disobeying
safety rules to let plants keep the cost down and
stay open to operate (Microsoft Encarta). Two
senior engineers started questioning after one of
them had checked the specifications of the cooling
system in a power plant.
After eighteen months of operation, a nuclear
power plant is temporarily shut down. They have
to get rid of the used fuel rods and replace them
with new ones. The old rods are very hot and
radioactive. Places to store the old fuel rods are
rather limited, especially since the federal
government has never designated an official
storage place for this high-level waste. So where
do you used fuel rods go?
Used fuel rods are kept at a fuel pool at the plant
until they can find a storage place for them. Fuel
pools were created to keep the fuel rods for short
periods of time. The fuel pool is not supposed to
be filled to capacity. This is only to be a last
resort. In the fuel pool, a cooling system cools the
used, hot, radioactive fuel rods. The more fuel
rods that are stored, the more heat. This, in turn,
causes more danger. If the cooling system fails, the
pool could boil, turning the plant into a lethal sauna
filled with radioactive steam (Microsoft Encarta).
George Galatis, an employee at Millstone-1
Nuclear Facility, had been checking specifications
and realized that the reports of safety in the fuel
pool had not been kept. He did some checking of
his own on this, and discovered that the plant had
been putting almost three times as many fuel rods
in the fuel pool as they were supposed to. He
wanted to report this to the NRC right away, but
he knew that some nuclear facilities, like this one,
was known to harass and even fire employees
who raised safety concerns. Therefore, he teamed
up with another employee at the plant, George
Betancourt, and brought the issue up to the
supervisors of the plant. They completely denied
the problem. Galatis and Betancourt then took the
problem to the NRC themselves and found that
the NRC had been ignoring the problem for over a
decade.
Nuclear facility scandals have not just been
happening recently. They have been going on since
the very beginning of nuclear energy. The nuclear
accident of Chelyabinsk-40 is one of the
earliest-known disasters. The Chelyabinsk-40
reactor was located near the Ural Mountains in the
city of Kyshtym, Russia. A tank holding
radioactive gases exploded, contaminating land
thousands of miles around the plant. Until 1988,
Russia officials dared to admit that this event even
took place. Many things are still unknown about
this disaster. What we do know, however, is that
the region around the reactor is sealed, and more
than 30 towns in the area around it have
disappeared from the Soviet map (Galperin 74).
In a town several miles north of Liverpool,
England, there was the nuclear repossessing plant
called Windscale. In 1957, the plant graphite
moderator overheated. The temperature indicators
did not recognize the problem in time, so a large
amount of radiation escaped, contaminating two
hundred miles of countryside. This accident is said
to have caused birth defects, cancer, and leukemia
in many people who were near the site (Schneider
4).
In 1975, at Brown?s Ferry Nuclear Plant in
Decatur, Alabama, there was another nuclear
accident. A maintenance worker was checking air
leaks with a candle. This was against regulations
and caused the plant to catch on fire. A meltdown
was luckily prevented, but a worse disaster
certainly could have happened (Galperin 75).
The worst nuclear accident in the United States
occurred in 1979 at Three Mile Island. This
reactor was located in Harrisburg, Pennsylvania.
Many of these reactors had poor safety records
and an NRC inspector suggested that they be
evaluated. Despite this inspector?s suggestion,
nothing was done. During the cleaning of a sector
of the plant, one pump failed which caused the
temperatures to rise in the cooling circuit. The
safety devices had turned on and started to work
properly. However, after they cooled the circuit,
the safety devices never turned off. They
eventually used all the coolant and the
temperatures began to rise. A meltdown began
and citizens started evacuating. It is uncertain how
much radiation escaped into the air from it. The
plant then had to be cleaned up and sealed off.
Part of this process is still going on, and the
estimated cost upon completion is around two
billion dollars (Stephens 174).
The Chernobyl nuclear disaster in Russia was the
worst accident in nuclear history. It took three
days of meltdown for the nuclear plant officials to
even realize there was a problem. The problem
was discovered when technicians in countries
bordering Russia noticed high radiation levels and
decided it was coming from Chernobyl.
Explosions were shooting radiation into the air
because Chernobyl was not built with a
containment structure. The radiation was carried
great distances by the air currents. The radiation
that escaped into the atmosphere was more
radioactive than the atomic bombs dropped on
Hiroshima and Nagasaki. Fires also raged
throughout the complex, which made it hard to
control the situation. It was stated that five million
people were exposed to the radioactive fallout in
Ukraine, Belarus, and Russia. Predictions were
made that 40,000 cases of cancer are going to be
linked directly to the Chernobyl accident (Galperin
82).
Chernobyl and other accidents help create a
growing resistance to nuclear energy. This is
because radiation sickness and other harmful
effects from over-exposure to radiation have
occurred. Every person in the world is exposed to
radiation. It comes from things such as potassium
in food, radon gases, and uranium decay. The
amount of radiation one is exposed to depends on
location, eating habits, as well as many other
things. Yet, too much radiation exposure is
definitely fatal.
How can nuclear power plants be trusted when
they are more concerned with saving money, then
protecting lives? They are violating safety
standards and the government is just watching
them do it. There are probably many other
violations that are taking place to let the plants
continue to operate and compete as a source of
power. If the NRC suddenly decided to enforce
all of its rules, then a majority of nuclear power
plants would have to be shut down. What do you
believe holds more importance: saving money, or
saving lives?
Nuclear energy displays both the brilliance of man
and the devastating destruction that mankind can
cause. The potential of nuclear energy has caused
great excitement. However, the destruction of
Hiroshima and Nagasaki, as well as the many
nuclear power plant accidents and the many
dangers of radioactivity, have given the world
reason to pause and consider the dangerous
possibilities of nuclear disaster.