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Transcript of Nuclear Fission Reactions - Ms. Kube's Webpage€¦ · The Tsar Bomba, detonated by the Soviet...
Nuclear Fission Reactions
Essential Standard 2.3
Understand the role of the nucleus in
radiation and radioactivity.
Learning Objective 2.2.6
Compare nuclear fusion and fission
reactions including alpha decay, beta
decay, and gamma decay.
I Can StatementsAt the end of this lesson, you should be
able to say, with confidence:
• I can explain what happens during nuclear
fission reactions
• I can list two uses of nuclear fission.
• I can describe the benefits and drawback
of using nuclear power as an energy
source.
Nuclear ReactionsThere are two types of nuclear reactions:
Nuclear Fusion and Nuclear Fission.
Nuclear Reactions
During nuclear fusion
reactions, smaller particles or
atoms are fused together to
form larger atoms.
During nuclear fission
reactions, larger atoms
split apart into smaller
atoms and neutron
particles.
Nuclear FissionDuring nuclear fission, free neutrons strike an
atom, splitting it into smaller atoms while also
releasing free neutrons.
Chain ReactionThe free neutrons then go on to split other atoms
causing multiple chain reactions.
Use of Nuclear Fission
Nuclear fission is used in
nuclear bombs to set off
uncontrolled chain
reactions.
Nuclear fission is also
used at nuclear power
plant, but in this case
the chain reactions are
controlled .
Nuclear BombsIn a nuclear bomb such as that used on Hiroshima,
uranium is shot at another source of uranium,
triggering a series of uncontrolled chain reactions.
Hiroshima
Nuclear BombsToday’s nuclear bombs are thousands times more
powerful than those dropped on Japan.
The Tsar Bomba,
detonated by the Soviet
Union in 1961, was
3,333 times more
powerful than Little Boy.
Here’s How Much Deadlier Today’s Nukes are Compared to WWII’s
A-Bombs, by Popular Mechanics
Nuclear Power PlantsNuclear fission is also used in nuclear power plants, but
in this case the chain reaction is controlled.
In order to control the
reaction, power plants
provide a source such
as boron and carbon,
to accept the free
neutrons.
The boron carbide compound is placed in long
cylindrical tubes called control rods.
Nuclear Power PlantsThe nuclear power source, usually uranium, is placed
into fuel pellets that are then placed into fuel rods.
The control rods are
lowered between the fuel
rods, when they want to stop
the reaction or lifted when
they want to begin reactions.
Control Rods
Nuclear Reactor
Another way to control the
nuclear reaction is by ensuring
all of the nuclear reactions
take place under water.
All of the nuclear
reactions take place
inside a nuclear
reactor that is
encased in layers of
cement and steel.
Nuclear ReactorThe heat from the nuclear reactions is used to
change water into steam.
The turning of the magnet inside the wire coil
generates electricity.
The steam is then
used to turn a
turbine that is
connected to a
magnet inside a
gigantic wire coil.
Nuclear Reactor WaterThe water that the fuel rods are immersed in is always
kept separate from the water that is turned into steam.
The radioactive water in the diagram is red and yellow
and the water turned into steam is blue. Notice they are
each in separate closed systems.
Source of Steam Water
Nuclear power plants, such
as the Shearon Harris Plant,
in Wake County, NC, are
always built near a body of
water (Lake Jordan).
To cool the steam so it
can be used again,
water from a nearby
body of water is used
to condense the steam
back into water.
Currently, nearly 20% of
all electricity in the
United States is
produced by nuclear
power plants.
Some European
nations, especially
France, use nuclear
power to generate
nearly all of their
electricity.
Nuclear Power Use
France
Benefits of Nuclear PowerNuclear power costs
less to produce than
fossil fuels and is far
more efficient with 90%
of energy being turned
into electricity.
Nuclear power requires less raw material than
fossil fuels. (20 g Uranium = 444 kg Coal)
Benefits of Nuclear Power
Nuclear power is also very clean in that it releases no carbon dioxide that accelerates the greenhouse effect and global climate change.
It also releases no sulfur and nitrogen oxides that
mix with water in the atmosphere to produce acid rain, like coal does.
Benefits of Nuclear PowerOf the other clean energy sources, such as wind
and solar power, nuclear power requires the least
amount of land and is much more reliable.
The largest drawback from
nuclear power is the large
amounts of radioactive
wastes generated.
A typical nuclear power
plant generates 20
metric tons of nuclear
waste each year.
Drawbacks of Nuclear Power
Structure Represents a Metric Ton
Drawbacks of Nuclear PowerThe half-life or Uranium is 4.5 billion years.
The means that of the 20 metric tons, after 4.5
billion years, 10 metric tons will still be left.
Half-life will be covered more in depth during the radioactive decay lesson
Drawbacks of Nuclear PowerA major question becomes where is all of that
radioactive waste going to be stored for such a long
period of time?
Nobody wants
the nuclear
wastes in their
backyard.
Storage of Nuclear WastesCurrently nuclear wastes are stored in steel-line,
concrete pools under about 20 feet of borated
water for 6 years, at the nuclear power plants.
The water keeps the
wastes cool as they
continue to go through
radioactive decay.
Nuclear Waste Storage in Pools
at Nuclear Power Plants
Storage of Nuclear WastesAfter 6 years, the nuclear waste is placed inside
steel canisters that are placed into reinforced
concrete containers, called dry casks.
The dry cask storage
allows the radioactive
wastes to cool off
naturally, while still
protecting the
environment.
Dry Cask Storage at
Nuclear Power Plants.
Periodically, there is talk
about storing all the wastes
underneath Yucca Mountain
in Nevada.
Yucca Mountain
But two-thirds of the people in Nevada oppose the site, mainly
because they don’t even have a nuclear power plant.
The What If? FactorThe United States rigorously maintains their nuclear
power plants and there has never been an actual
issue of nuclear contamination in the United States.
However, there is always the
possibility of nuclear
contamination occurring.
This is most common concern
of people who object to
nuclear power.
In 1986 in the Ukraine part of the Soviet Union, a nuclear reactor underwent a meltdown resulting in radioactive
related deaths, cancer and birth defects.
Chernobyl
But, the Soviet Union wasn’t maintaining the nuclear power plant and they didn’t even warm the people after the
meltdown occurred.
Chernobyl: What Really Happened
FukushimaIn 2011 in Fukushima, Japan, nuclear reactors also
underwent a meltdown after an earthquake and tsunami.
Over 160,000 people were forced to evacuate
their homes.
The End