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19890848
Nuclear Power

Plants

Nuclear Power Plants

Electricity produced by nuclear fission — splitting the atom — is one
of the greatest uses of radiation. As our country becomes a nation of
electricity users, we need a reliable, abundant, clean, and affordable
source of electricity. We depend on it to give us light, to help us
groom and feed ourselves, to keep our homes and businesses
running, and to power the many machines we use. As a result, we
use about one-third of our energy resources to produce electricity.

Electricity can be produced in many ways — using generators
powered by the sun, wind, water, coal, oil, gas, or nuclear fission. In
America, nuclear power plants are the second largest source of
electricity (after coal-fired plants) — producing approximately 21
percent of our Nation's electricity.

The purpose of a nuclear power plant is to boil water to produce
steam to power a generator to produce electricity. While nuclear
power plants have many similarities to other types of plants that
generate electricity, there are some significant differences. With the

exception of solar, wind, and hydroelectric plants, power plants
(including those that use nuclear fission) boil water to produce steam
that spins the propeller-like blades of a turbine that turns the shaft of
a generator. Inside the generator, coils of wire and magnetic fields
interact to create electricity. In these plants, the energy needed to
boil water into steam is produced either by burning coal, oil, or gas
(fossil fuels) in a furnace, or by splitting atoms of uranium in a
nuclear power plant. Nothing is burned or exploded in a nuclear
power plant. Rather, the uranium fuel generates heat through a
process called fission.

Nuclear power plants are fueled by uranium, which emits radioactive
substances. Most of these substances are trapped in uranium fuel
pellets or in sealed metal fuel rods. However, small amounts of these
radioactive substances (mostly gases) become mixed with the water
that is used to cool the reactor. Other impurities in the water are also
made radioactive as they pass through the reactor. The water that
passes through a reactor is processed and filtered to remove these
radioactive impurities before being returned to the environment.
Nonetheless, minute quantities of radioactive gases and liquids are

ultimately released to the environment under controlled and
monitored conditions.

The U.S. Nuclear Regulatory Commission (NRC) has established
limits for the release of radioactivity from nuclear power plants.
Although the effects of very low levels of radiation are difficult to
detect, the NRC's limits are based on the assumption that the public's
exposure to man-made sources of radiation should be only a small
fraction of the exposure that people receive from natural background
sources.

Experience has shown that, during normal operations, nuclear power
plants typically release only a small fraction of the radiation allowed
by the NRC's established limits. In fact, a person who spends a full
year at the boundary of a nuclear power plant site would receive an
additional radiation exposure of less than 1 percent of the radiation
that everyone receives from natural background sources. This
additional exposure, totaling about 1 millirem (a unit used in
measuring radiation absorption and its effects), has not been shown
to cause any harm to human beings.

Managing Nuclear Technology | Nuclear Science and Engineering | MIT ...
Nuclear-powered ships

Nuclear-powered ships

Nuclear power is particularly suitable for vessels which need to be at
sea for long periods without refuelling, or for powerful submarine
propulsion. The majority of the approximately 140 ships powered by
small nuclear reactors are submarines, but they range from
icebreakers to aircraft carriers.

See also information paper on Nuclear-Powered Ships.

Nuclear reactors for space

Radioisotope thermal generators (RTGs) are used in space missions.
The heat generated by the decay of a radioactive source, often
plutionium-238, is used to generate electricity. The Voyager space
probes, the Cassini mission to Saturn, the Galileo mission to Jupiter,
and the New Horizons mission to Pluto are all powered by RTGs. The
Spirit and Opportunity Mars rovers have used a mix of solar panels
for electricity and RTGs for heat. The latest Mars rover, Curiosity, is
much bigger and uses RTGs for heat and electricity as solar panels
would not be able to supply enough electricity.

See also information paper on Nuclear Reactors for Space.

Hydrogen, electricity and cars

In the future, electricity or heat from nuclear power plants could be
used to make hydrogen. Hydrogen can be used in fuel cells to power
cars, or can be burned to provide heat in place of gas without
producing emissions that would cause climate change.

See also information paper on Transport and the Hydrogen
Economy.

19890848


Title Card
Nuclear Power Plants
Text Card


Nuclear Power Plants

Electricity produced by nuclear fission — splitting the atom — is one of the greatest uses of radiation. As our country becomes a nation of electricity users, we need a reliable, abundant, clean, and affordable source of electricity. We depend on it to give us light, to help us groom and feed ourselves, to keep our homes and businesses running, and to power the many machines we use. As a result, we use about one-third of our energy resources to produce electricity.

Electricity can be produced in many ways — using generators powered by the sun, wind, water, coal, oil, gas, or nuclear fission. In America, nuclear power plants are the second largest source of electricity (after coal-fired plants) — producing approximately 21 percent of our Nation's electricity.

The purpose of a nuclear power plant is to boil water to produce steam to power a generator to produce electricity. While nuclear power plants have many similarities to other types of plants that generate electricity, there are some significant differences. With the exception of solar, wind, and hydroelectric plants, power plants (including those that use nuclear fission) boil water to produce steam that spins the propeller-like blades of a turbine that turns the shaft of a generator. Inside the generator, coils of wire and magnetic fields interact to create electricity. In these plants, the energy needed to boil water into steam is produced either by burning coal, oil, or gas (fossil fuels) in a furnace, or by splitting atoms of uranium in a nuclear power plant. Nothing is burned or exploded in a nuclear power plant. Rather, the uranium fuel generates heat through a process called fission.

Nuclear power plants are fueled by uranium, which emits radioactive substances. Most of these substances are trapped in uranium fuel pellets or in sealed metal fuel rods. However, small amounts of these radioactive substances (mostly gases) become mixed with the water that is used to cool the reactor. Other impurities in the water are also made radioactive as they pass through the reactor. The water that passes through a reactor is processed and filtered to remove these radioactive impurities before being returned to the environment. Nonetheless, minute quantities of radioactive gases and liquids are ultimately released to the environment under controlled and monitored conditions.

The U.S. Nuclear Regulatory Commission (NRC) has established limits for the release of radioactivity from nuclear power plants. Although the effects of very low levels of radiation are difficult to detect, the NRC's limits are based on the assumption that the public's exposure to man-made sources of radiation should be only a small fraction of the exposure that people receive from natural background sources.

Experience has shown that, during normal operations, nuclear power plants typically release only a small fraction of the radiation allowed by the NRC's established limits. In fact, a person who spends a full year at the boundary of a nuclear power plant site would receive an additional radiation exposure of less than 1 percent of the radiation that everyone receives from natural background sources. This additional exposure, totaling about 1 millirem (a unit used in measuring radiation absorption and its effects), has not been shown to cause any harm to human beings.





Managing Nuclear Technology | Nuclear Science and Engineering | MIT ...
Nuclear-powered ships

Text Card


Nuclear-powered ships

Nuclear power is particularly suitable for vessels which need to be at sea for long periods without refuelling, or for powerful submarine propulsion. The majority of the approximately 140 ships powered by small nuclear reactors are submarines, but they range from icebreakers to aircraft carriers.

See also information paper on Nuclear-Powered Ships.

Nuclear reactors for space

Radioisotope thermal generators (RTGs) are used in space missions. The heat generated by the decay of a radioactive source, often plutionium-238, is used to generate electricity. The Voyager space probes, the Cassini mission to Saturn, the Galileo mission to Jupiter, and the New Horizons mission to Pluto are all powered by RTGs. The Spirit and Opportunity Mars rovers have used a mix of solar panels for electricity and RTGs for heat. The latest Mars rover, Curiosity, is much bigger and uses RTGs for heat and electricity as solar panels would not be able to supply enough electricity.

See also information paper on Nuclear Reactors for Space.

Hydrogen, electricity and cars

In the future, electricity or heat from nuclear power plants could be used to make hydrogen. Hydrogen can be used in fuel cells to power cars, or can be burned to provide heat in place of gas without producing emissions that would cause climate change.

See also information paper on Transport and the Hydrogen Economy.