Transcript Slide 1 - Bremen High School District 228

Nuclear fission
• When an atomic nucleus is split into smaller
atomic nuclei
– Does not occur in nature
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Nuclear Energy
Nuclear fission - used in power plants to generate
electricity for homes and industry.
- In 2012, supplied approximately 13% of the world’s electricity
- In U.S., 65 power plants in 31 states. Supplies 20% of our
electricity.
- Uranium-235 is most commonly used
Nuclear Energy
Nuclear power plants use nuclear fuel to create heat which
boils water, creating steam, which turns the turbine to
generate the electricity.
Video: http://www.youtube.com/watch?v=D91T-B-PVE0&feature=youtu.be
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Nuclear Fusion
• When two or more atomic nuclei collide at a very
high speed and join to form a new atomic nucleus.
Fission has 2 s’s so 2 are made, Fusion has one s so 1 is made.
Video: http://www.youtube.com/watch?v=fSr3V498A3I
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Nuclear Fusion
Occurs in nature
• Energy from sun is produced by nuclear reactions
in its core from the collision of hydrogen nuclei and
the formation of helium nuclei.
– Energy from all other stars too.
• Evidence for the Big Bang Theory on how the
universe began.
Video: http://www.youtube.com/watch?v=uKqvjEE0wFg
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National Defense
and Nuclear Weaponry
•The “Manhattan Project” – U.S. project to make a
nuclear weapon
•Atomic bomb – first used to end WWII
•Tested in New Mexico July 1945
•Used in warfare in Hiroshima and
Nagasaki, Japan in Aug 1945
Effects
Immediate explosion
Cancer of survivors
Cancer of offspring of
survivors
National Defense
and Nuclear Weaponry
What’s the difference?????
• Nuclear bomb uses fission or fusion
– Fusion releases more radioactive particles and greater
energy than fission
• Types of nuclear bombs
– Hydrogen bomb uses fusion and fission (more
powerful) aka thermonuclear bomb
– Atomic bomb uses nuclear fission.
• Uranium and Plutonium Bombs.
3 mile Island Accident- March 28, 1979
• Three Mile Island nuclear power plant Harrisburg,
Pennsylvania in the US had a malfunction.
• Some radioactive gas was released, but not
enough for concern.
• There were no injuries or adverse health effects
from the Three Mile Island accident.
Chernobyl Accident- April 26, 1986
• World’s worst nuclear power plant accident
•4 reactors (2 built in 1970’s, 2 in 1980’s)
• Combination of design and operator error during electrical power safety
check resulted in cascade of events leading to core breach of Reactor 4 with
subsequent chemical (not nuclear) explosion
http://www.youtube.com/watch?v=_hZHKPGpop8
Chernobyl Accident continued
• Released - I-131 (half life= 8 days), later Cs-137 (half life= 30 years)
•Children particularly susceptible to I-131. Thyroid takes up I- to
produce the hormone thyroxine (T4, growth/metabolism).
•I-131 decays be beta emission with accompanying gamma ray
•If ingested, can cause thyroid cancer
•About 4000 cases of thyroid cancer in exposed children (2000), nine
related deaths in this group
Fukushima Accident- March 11, 2011
Following a major earthquake, a 15-metre tsunami
disabled the power supply and cooling of three
Fukushima Daiichi reactors, causing a nuclear
accident