Environmental_Science

1. “Nuclear power is a hell of a way to boil water.”
- Albert Einstein

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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3. One-Hundred Ton Test, 0.1 kilotons 4

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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8. Trinity, 21 kilotons 9

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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13. Shot Able and Shot Baker 14

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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16. Castle Bravo, 15 megatons (15000 kilotons) 17

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.
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Cooling
Tower in
Byron, Illinois

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 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.

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 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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