Nuclear Chemistry,
Chapter 18
Introduction
• Remember that ISOTOPES are atoms with
different masses due to different numbers of
NEUTRONS.
• Rutherford’s Gold Foil expt. showed that all of the mass
of the atom is in the nucleus.
http://www.youtube.com/watch?v=NlDPPANJZXM or
use the pHet Rutherford Scattering simulation:
http://phet.colorado.edu/en/simulation/rutherfordscattering
• Nucleus = protons + neutrons
• Together they are called NUCLEONS.
• NUCLIDES are atoms identified by both mass and
number. ex: 1
•
1
What force holds nuclei together?
• Called the Strong Force.
• Identified by Hideki Yukawa
• MUCH stronger than charge interactions but
only strong over a VERY SHORT DISTANCE.
• Strong force must be stronger than the force
pulling the nucleons apart (repulsion due to
charge), so in large nuclei, where due to
distance the pull is less, the nuclei tend to fall
apart.
Are there smaller nuclear particles
than neutrons and protons?
• Dalton—atoms are the smallest particles in
nature
• Other scientists—there are protons and
neutrons.
• 1960—protons and neutrons are made of
QUARKS.
Quark FLAVORS
1.
2.
3.
4.
5.
6.
Up
Down
Top
Bottom
Strange
Charm
ONLY Up and Down make up Protons and Neutrons.
Beta decay
A neutron released from an unstable nucleus can be converted into
A Proton and an Electron + energy. The Electron is also called a Beta Particle.
http://chemed.chem.purdue.edu/genchem/to
picreview/bp/ch23/modes.php#radiation
http://www.ndted.org/EducationResources/HighSchool/Radio
graphy/radioactivedecay.htm
Bad Health Effects of
Radiation
• Genetic damages: from mutations
that alter genes
• Genetic defects can become
apparent in the next generation
• Somatic damages: to tissue, such as
burns, miscarriages & cancers
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Electricity Production by Fuel
Electricity Production by Fuel
9%
Coal
Hydroelectric
Power
Other
23%
56%
Nuclear
3%
9%
U.S. Department of Energy, Annual Energy Review 1999
Natural Gass
Use of Fission Power
• 1945
• first large scale use
• atomic bombs were used by
the US to knock Japan out
of WWII
– since then attention has
been given to the peaceful
uses of atomic energy
Nuclear Power Plants
• In a conventional nuclear power
plant
–a controlled nuclear fission chain
reaction
–heats water
–produce high-pressure steam
–that turns turbines
–generates electricity.
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Nuclear Fission
• approximately 20,000 times as
much heat and energy is released
from uranium fuels as from an
equivalent amount of coal
• when a sufficient amount of
fissionable material is brought
together, a chain reaction occurs
splitting atoms and releasing a
tremendous amount of heat
Nuclear Fission
Controlled Fission
Chain Reaction
neutrons split the
nuclei of atoms such
as Uranium or
Plutonium
release energy (heat)
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
http://phet.colorado.edu/en/simulation/nucle
ar-fission
http://www.youtube.com/watch?v=vjqIJW_Qr
3c
Nuclear Fusion
• Fusion is combining together
• the atoms are fused together
rather than split apart
• possibilities for nuclear fusion are
much greater than those for
nuclear fission
Fuel for fusion
• fusion reactors would be fueled
by deuterium, an isotope of
hydrogen
• available in almost unlimited
supply in sea water
Fusion
Problems:
• process is so difficult to control that it is
questionable whether commercial
adaptation will ever be economically
feasible
• Can be done in a lab –held in check by
magnetic fields.
• BUT—creates HUGE amounts of heat.
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Fusion Problems
• fusion requires extreme pressure
and temperatures (as high as 100
million degrees)
• such heat was achieved by the
Hydrogen bomb by first setting
off a fission explosion
Destructive power:
[1] Small towns have been leveled by floods and landslides.
[2] The same size town could be leveled by 1,000 tons of chemical
explosives.
[3] Hiroshima (quarter of a million people) was destroyed by
releasing the energy in 40 kg of Uranium
We know the least about the strong nuclear force.
Nuclear Energy Concerns
• Concerns about the safety, cost,
and liability have slowed the
growth of the nuclear power
industry
• Accidents at Chernobyl and
Three Mile Island, and more
recently, Fukashima, showed that
a partial or complete meltdown is
possible
Chernobyl
• April 26, 1986, reactor explosion (Ukraine) flung
radioactive debris into atmosphere
• Health ministry reported 3,576 deaths
• Green Peace estimates 32,000 deaths;
• About 400,000 people were forced to leave their
homes
• ~160,000 sq km (62,00 sq mi) contaminated
• > Half million people exposed to dangerous levels of
radioactivity
• Cost of incident > $358 billion
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Three Mile Island
• March 29, 1979, a reactor near Harrisburg, PA lost
coolant water because of mechanical and human
errors and suffered a partial meltdown
• 50,000 people evacuated & another 50,000 fled area
• Unknown amounts of radioactive materials released
• Partial cleanup & damages cost $1.2 billion
• Released radiation increased cancer rates.
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Three Mile Island
• evacuation of preschool children
and pregnant women within five
miles of the plant
Radioactive Waste
1. Low-level radiation (Gives of low amount of
radiation)
• Sources: nuclear power plants, hospitals &
universities
• 1940 – 1970 most was dumped into the ocean
• Today deposited into landfills
2. High-level radiation (Gives of large amount of
radiation)
• Fuel rods from nuclear power plants
• Half-time of Plutonium 239 is 24000 years
• No agreement about a safe method of storage
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
Radioactive Waste
1. Bury it deep underground.
• Problems: i.e. earthquake, groundwater…
2. Shoot it into space or into the sun.
• Problems: costs, accident would affect large area.
3. Bury it under the Antarctic ice sheet.
• Problems: long-term stability of ice is not known,
global warming
4. Most likely plan for the US
• Bury it into Yucca Mountain in desert of Nevada
• Cost of over $ 50 billion
• 160 miles from Las Vegas
• Transportation across the country via train & truck
www.bio.miami.edu/beck/esc101/Chapter14&15.ppt
What is Going to Happen to Spent
Fuel?
Photos from :
The Yucca Mountain Project:
http://www.ymp.gov
http://hereandnow.wbur.org/2014/02/28/nuclear-radiation-carlsbad
/
Conclusion……
• “The odds of an American dying
from a nuclear power accident
are 300 million to one.”