2. On May 7, 1945, 108
tons of TNT stacked
and threaded with
radioactive material
was detonated in the
White Sands desert in
New Mexico.
This explosion was
meant to calibrate the
instruments that
would measure the
actual nuclear bombs
to be tested later.
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4. Nuclear technology takes advantage of the power
locked in structure of atoms, the basic particle of
matter.
The nucleus of an atom
contains all of its
positively-charged protons
and non-charged neutrons.
Negatively-charged electrons
orbit the nucleus.
Atoms always contain equal numbers of protons and
electrons, , making them electrically neutral.
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5. Atoms can have different
numbers of neutrons in their
nuclei.
Nuclei from the same element
with different numbers of
neutrons are called isotopes.
Most isotopes are stable, but
some can spontaneously break
apart, emitting energy and
particles.
This is radiation.
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6. Nuclear weapons harness a specific type of decay called
nuclear fission.
This is the splitting of the nucleus into two smaller
fragments.
The fuel used by the first
nuclear weapons was
Uranium-235, a naturally
occurring isotope.
Uranium-235 has an
extremely large nucleus
that can be split when it
is hit with a high-speed
neutron.
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7. In a nuclear bomb, a large amount of uranium-235 is
clustered together, so that when fission is initiated in
one of the atoms, it splits and released more neutrons,
which then cause fission in other atoms.
This creates a fission chain
reaction.
Each time a nucleus splits,
a large amount of energy is
released.
Multiplied across the entire
chain reaction…
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9. The first nuclear test detonation used a device that was
an exact replica of “Fat Man”, which would later be
dropped on Nagasaki, Japan.
The heat of the explosion fused the desert sands
together, forming a layer of radioactive green glass.
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10. 11
Two atomic bombs were dropped during World War II –
Hiroshima and Nagasaki, Japan.
Each had yields of 15-21 kilotons of TNT.
These blasts ended World War II.
Hiroshima, March 1946.
11. Following World War 2, additional nuclear weapons
testing was moved to part of the Marshall Islands, called
the Bikini Atoll (11°N, 165°E).
This testing was codenamed “Operation Crossroads.”
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12. Two nuclear devices were detonated at sea as part of
Operation Crossroads.
The purpose was to study the effects of a nuclear blast on
an armada of naval ships.
The first blast, called Shot Able, was dropped from a
plane. The second, Shot Baker, was detonated
underwater, beneath the
ships.
Different species of lab
animals were placed
on several ships, to test
for radiation poisoning
following the blast.
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14. Glenn Seaborg,
chairman of the
Atomic Energy
Commission, called
Baker “the world’s
first nuclear disaster.”
The target ships of Shot
Baker were all heavily
contaminated with
radioactive fallout.
Some were so “hot” that they could not be safely
decontaminated and had to be sunk.
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15. In 1954, six large nuclear tests were conducted. The
largest was code named Castle Bravo.
This tested a new design, called a hydrogen bomb.
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17. 18
Castle Bravo was a much more
powerful blast than expected.
Residents of nearby atolls were
exposed to toxic levels of
radioactive fallout.
A Japanese tuna fishing boat
called the Lucky Dragon 5 was
also caught in the blast radius.
18. Nuclear fallout is dust and ash propelled into the
atmosphere following a nuclear blast.
Radiation exposure from fallout is measured in rems.
100-200 rems causes mild symptoms, such as nausea and
vomiting.
400-600 rems has about a 50% mortality rate.
600-1000 rems will usually cause death.
Over 1000 rems will cause death in a few hours or less.
Interior exposure of fallout, from breathing or ingesting
the dust and ash, would have even more severe effects.
An average person will be exposed to about 620
millirems of radiation per year from natural and man-
made sources.
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19. Radioactive coral dust fell on the Lucky Dragon 5.
Fishermen touched the dust with their bare skin, inhaled
it, and in some cases, tasted it.
One crewmember died from exposure.
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20. As the Bikini nuclear testing continued, President
Dwight Eisenhower gave a famous speech to the United
Nations:
“My country wants to be
constructive, not destructive.”
“…the United States pledges before you…
its determination to help solve the
fearful atomic dilemma--to devote its
entire heart and mind to find the way by
which the miraculous inventiveness of man
shall not be dedicated to his death, but
consecrated to his life."
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21. Equipment and technology were provided to schools,
hospitals, and research institutions to help develop
nuclear technology towards more peaceful goals.
The primary goal: electricity generation.
Optimism for the new technology was very high.
Lewis Strauss, chairman of the Atomic Energy
Commission, predicted that,
“Our children will enjoy in
their homes electrical energy
too cheap to meter.”
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22. The process of
converting nuclear
energy into electricity
is similar to that of
using fossil fuels.
Water is boiled, the
steam is passed
through a turbine,
which spins a
generator.
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23. As with nuclear bombs, the primary fuel is uranium-235.
Uranium ore is enriched and formed into fuel pellets.
The fuel pellets are stacked into long, cylindrical fuel rods.
Control rods, made of a neutron-absorbing material, are
placed amongst the fuel rods.
Can be removed and inserted to adjust the rate of the chain
reaction.
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Withdraw
control
rods,
reaction
increases
Insert control
rods,
reaction
decreases
24. One big advantage to nuclear power is that, under
normal conditions, it does not release any air pollution,
only steam.
25
Cooling
Tower in
Byron, Illinois
25. 26
Both reactor vessel and
steam generator are housed
in a special containment
building preventing
radiation from escaping,
and providing extra
security in case of
accidents.
Under normal operating
conditions, a reactor
releases very little
radioactivity.
27. Through the late
1970s, many new
reactors were
constructed all over
the United States.
Since that initial
boom, few new
reactors have come
online.
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28. 29
In 1979, a movie called “The China
Syndrome” was released.
Fictional story about a California
nuclear plant that experienced a
near-meltdown of its nuclear core.
The title of the movie is an
exaggeration of what happens
during a meltdown – the nuclear
core becomes so hot that it melts,
even melting through the floor of
the reactor vessel.
29. 30
Ten days following the movie’s release, the Three Mile
Island partial meltdown occurred.
A relief water valve stuck open, allowing water to escape
from the core.
A meltdown, when the fuel and control rods physically
begin to melt due to the heat surge within the reactor,
partially occurred.
No major leak to the
environment occurred.
30. In 1986, a full meltdown occurred at the Chernobyl
nuclear plant located in Ukraine (formerly Soviet
Union).
A test was being conducted on the reactor to see how the
backup water pump generators would respond to a full
power outage.
The control rods were fully removed.
At some point, the fission chain reaction began occurring
uncontrollably.
An explosion ripped apart the containment building,
spreading radioactive fallout throughout the area and into
the atmosphere.
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31. There were multiple design flaws at the Chernobyl plant:
The containment building was inadequate.
Graphite was used as a
moderator instead of
water. When the
meltdown occurred, it
ignited, releasing more
fallout.
A water storage pool
was located under the
reactor. If the core had
melted down into this
pool, an even greater
explosion would have occurred.
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32. The burning core was eventually extinguished.
The nearby employees’ town, Pripyat, was permanently
evacuated.
A 30km radius around the plant, called the exclusion
zone, has been designated as uninhabitable to people.
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33. The most recent meltdown occurred following a massive
earthquake and tidal wave off the coast of Japan.
The generators powering the water pumps of some of the
Fukushima Daiichi reactors were flooded.
Without cooling water, the core overheated and
experienced a meltdown.
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34. Contaminated water from the plant leaked into the
Pacific.
Top predators, like bluefin tuna, caught in the Pacific
have positively tested for small amounts of radioactive
fallout.
A single serving of tuna has less than half of the exposure
from an arm x-ray.
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35. 36
About 100,000 tons of low-level
waste (clothing) and about 15,000
tons of high-level waste (spent-
fuel) waste is stored in the U.S.
from reactor usage.
Spent fuel rods are temporarily
placed in deep water pools while
they cool down and the fission
reaction slows.
Waste is then moved to large casks
of metal and concrete near the
reactor.
36. 37
The U.S. Department of Energy
announced plans to build a high-
level waste repository near Yucca
Mountain, Nevada in 1987.
The facility met three important
criteria for long-term waste
storage:
Low moisture.
Geologically stable.
Far away from major population
centers.
Plans to use Yucca have since
been halted, due to objections
from Nevada residents.
No long-term storage plan has
been accepted by the U.S.
37. Some alternative methods of nuclear waste
disposal have been researched.
Transmutation uses the waste as fuel in a
different type of reactor, which converts it to a
less-dangerous waste.
Geologic disposal involves
depositing the waste
deep below the Earth’s
crust in stable rock
formations.
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38. Nuclear energy makes up only a fraction of our
total energy generation.
Its use may increase in the future, as fossil fuels
become more scarce or are considered too
environmentally damaging.
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