Nuclear Chemistry
Applied Chemistry
When you think of the word NUCLEAR,
what does it bring to mind?
Radioactivity Discovery
 In 1896, Henri
Becquerel noticed that a
piece of uranium ore,
called pitchblende,
exposed a piece of
photographic film.
 Uranium gave off
invisible rays he called
uranic rays.
 Uranium is radioactive.
Marie & Pierre Curie: 1903




Shared the Nobel Prize
in Chemistry with
Becquerel.
They discovered 2 new
radioactive elements,
Radium and Polonium.
Marie called Radium the
“radiant” element and
Polonium she named for
her native Poland.
How do you think Marie
& Pierre died???
1867-1934
1859-1906
What happened to The Curies?
 Pierre was run over by a
horse-drawn wagon in Paris
and killed in 1906. Marie was
left alone with two daughters,
aged 2 and 9.
 In 1911 she went on to win a
second Nobel Prize in
chemistry.
 In 1934, Marie died of
leukemia brought on by
radiation exposure one year
before her daughter and sonin-law won the Nobel Prize
for Chemistry.
Radioactivity
 Radioactivity is the release of particles,
energy, or both from the nucleus of an
atom.
Radioactivity
Natural radioactivity is found on the
earth.
Everyone receives background radiation
at low levels from cosmic radiation,
ground, building materials, and food.
Exposure to radiation does not make
you or anything else radioactive.
Artificial radioactivity is produced in
the lab.
Types of Radiation -Energy
 Nonionizing radiation is radiation with low
energy.
Ex: radiowaves, infrared, and visible light
 Ionizing radiation is radiation with high
energy.
Ex: ultraviolet, x-ray, and gamma
Types of Radiation - Energy
Particles released from the nucleus of
an atom.
Examples: alpha and beta particles
Characteristics of Radiation
Type
Symbo
Composition
l
Alpha
particle

Beta
particle

Gamma
ray

2 protons &
2 neutrons
Helium nuclei
An electron
High Energy
Penetratio
n
Stopped
by…
Low
Sheet of
paper
Medium Aluminum
Foil
High
Thick
concrete
or lead
Nuclear Radiation Penetrating Power
Exposure and Uses of Radiation Radon
Radon is a decay product of uranium
found in the soil or bedrock.
This is natural radioactivity.
Radon is a colorless, odorless gas.
Some radon produced in the soil
dissolves in groundwater.
Radon
Many houses have cracks in the
foundation and basement floors that
permit radon to collect and concentrate.
Most radon enters your body by
breathing.
Radon decays by alpha emission to
produce heavy metals.
These heavy metals are not exhaled and
produce damaging alpha particles in your
body.
How Radon Gas Enters your House
Exposure and Uses of Radiation
Radon
Radon in your home can be checked
by you.
Increased ventilation and sealing
cracks in the floors are 2 ways you
can reduce radon exposure.
Testing Methods for Radon
Ways to Remove Radon Gas from Your Home
 External view of a
Radon mitigation system
from a home basement.
 Below is a view of the
fan inside which runs 24
hours a day pulling air
from under the basement
floor.
U.S. Radon Zones
Exposure and Uses of Radiation
Smoke Detectors
Smoke detectors
use americium
as the ionizing
source.
Americium emits
alpha particles.
Special disposal
of smoke
detectors is
required.
Exposure and Uses of Radiation
Some EXIT signs use tritium or
hydrogen-3 instead of electricity.
Aircraft dials
Luminous paints
Wrist watches
The tritium gas is contained in sealed
glass tubes. The insides of the tubes
are lined with a phosphor.
Low-energy Beta particles (electrons)
emitted by the tritium bombard the
phosphor, causing it to glow.
Exposure and Uses of Radiation
Agricultural and Consumer Product
 Many everyday products and food are treated
to kill bacteria and insects.
 Examples: fruits, poultry, cosmetics, band
aids
 Products are irradiated with gamma rays
from cobalt-60.(used by CFC Logistics in its irradiator)
 Irradiated products are not radioactive.
Irradiated Ground Beef
Medical Uses –
Diagnostic Equipment
Computer-Axial Tomography scans or
CAT scans use x-rays to produce crosssectional images of the brain.
Medical Uses –
Diagnostic Equipment
Magnetic Resonance Imaging or MRI
uses radiowaves to “see through”
bones to produce images of soft
tissue.
Medical Uses – Diagnostic Tools
using Radioisotope-Tracer studies
Radioisotopes prepared in a nuclear
reactor can be used to both treat and
detect various medical conditions.
Tracers can be used to follow a
particular isotope through its normal
path in the body to show any
abnormalities.
Tracers used in the body will typically
have short half-lives.
Radioisotopes
found in various
parts of the body
Exposure to Radiation
Devices used to measure
radioactivity
In the Lab:
 Geiger Counter
 In the Workplace:
 Film badge or Dosimeter
Measurements of Radioactivity
Units
 rad measures the absorbed radiation dose
 rem measures the ionizing effect on
living organisms.
 In humans, ionizing radiation is measured
in millirem, abbreviated mrem.
Radioactive Dating
 Used for
determining the age
of previously living
material.
 For material up to
25,000 years old,
carbon-14 is used.
 For material over
25,000 years old,
potassium-40 is
used.
Half-Life
Half-Life is the time for half of the
nuclei in a radioactive sample to
decay.
Abbreviated: t1/2
Units can vary from milliseconds to
thousands of years.
Half-Life
 Example: Plutonium-239 has a half-life of
24,000 years. A sample of this plutonium
today will be half gone in 24,000 years.
 A 16-g sample today will have a mass of 8 g
in 24,000 years.
 After another 24,000 years, its mass will be
only 4 g.
Half-life Problems
(amount problem – how much)
 A radioactive element has a half-life of 64
years. You have a 48 g sample of this
element. What is its mass in 192 years?
t1/2 = 64 yrs
t = 192 yrs
initial = 48 g
final = ?
1st determine the number of half-lives:
Number of half-lives =
t
t1/2
192 yr
=
=3
64 yr
2nd divide original mass by 2. How many times? As
many as the number of half-lives.
48 g
24 g
12g
1
2
3





 6g
2
2
2
Half-life Problems
(time problem – how long/old?)
 Another radioactive sample has a half-life of
37.2 minutes. How long will it take for a
55g sample to decay to 3.4g?
t1/2 = 37.2 min
initial = 55 g
t=?
final = 3.4 g
1st - Divide sample by 2 until final mass is reached.
55 g
27.5 g
13.75g
6.875g 4
1
2
3







 3.4375 g
2
2
2
2
2nd - Multiply t1/2 by the number of half-lives.
37.2 min x 4 = 148.8 min
Half-Life Practice Problems
1. The half-life for fluorine-18 is 109.8 minutes. How long will it take a 3.60 g sample to decay
to 0.225 g?
t1/2 = 109.8 min
initial = 3.60 g
time problem
total time = ???
final = 0.225 g
1st repeatedly cut your sample mass in half until you have 0.225 g.
3.60 g  1.80 g  0.90 g  0.45 g  0.225 g
1
2
3
4
2nd multiply the half-life by the number of times you cut the sample in half.
109.8 minutes x 4 =
439.2 minutes
2. The half-life for americium-241 is 432 years. How much of a 50 mg sample will remain after
1296 years?
t1/2 = 432 yrs
initial = 50 mg
amount problem
total time = 1296 yrs
final = ???
1st find the number of half-lives in 1296 years.
1296 years
432 years = 3
2nd cut your sample mass in half 3 times.
50 mg  25 mg  12.5 mg  6.25 mg
1
2
3
Nuclear Fission
Nuclear Fission is
the splitting of a
large nucleus in
to smaller nuclei
of similar size.
A small amount
of mass is
converted to a
large amount of
energy.
Nuclear Fission
U  n
235
92
1
0
140
56
Ba 
93
36
Kr  3 n  energy
1
0
Nuclear Fission Examples
Atomic bomb uses U-235 or
plutonium
1st military use of an atomic bomb
was in Hiroshima, Japan on August
6, 1945 during WWII.
Nuclear Power Plants
Nuclear Fission
 A chain reaction occurs when the material
used to start the reaction is also produced
until the fuel is used up.
U  n
235
92
1
0
140
56
Ba  Kr  3 n  energy
93
36
1
0
 In this fission reaction, the fuel is U-235
and the starter for the reaction is the
neutron.
Nuclear Chain Reaction - Fission
Fuel: U-235 or Pu-239
Critical mass for U is 110 lbs
Critical Mass is the minimum
amount of fissionable material
present (the fuel) to sustain a
chain reaction.
The first Atomic Bomb is detonated
at Trinity Site near Alamogordo,
New Mexico on July 16, 1945.
Video of 1st Atomic Bomb
A wooden house
built 1km away
from the test site…
A Monument
stands at the
test site today.
shows the
result of the
blast.
“Little Boy”
Uranium fission bomb
dropped on Hiroshima,
Japan by the “Enola Gay”
flown by Colonel Paul
Tibbets
Hiroshima - August 6, 1945
Distance from
Ground Zero
(km)
Killed
Injured
0 -1.0
86%
10%
31,020
1.0 - 2.5
27%
37%
144,800
2.5 - 5.0
2%
25%
80,300
Total
27%
30%
256,300
Population
Nagasaki - August 9, 1945
Distance from
Ground Zero
(km)
Killed
Injured
0 -1.0
88%
6%
30,900
1.0 - 2.5
34%
29%
144,800
2.5 - 5.0
11%
10%
15,200
Total
22%
12%
173,800
Population
“Fat Man” –
Plutonium Fuel
Hiroshima 1945 & Today
Nuclear Fusion
 Nuclear Fusion is the joining of smaller
nuclei to form a larger nucleus.
2 H  2 H  He  2 H  energy
1
1
2
1
4
2
1
1
 A small amount of mass is converted into a
large amount of energy that is 4-7 times
more than a fission reaction.
Nuclear Fusion
3
1
H  H  He  n  1.7x10 J/mol
2
1
4
2
1
0
12
Nuclear Fusion
Examples:
Sun
Hydrogen Bomb
We are currently unable to control
fusion as an energy source
Temperatures of 100 million °F are
required - thermonuclear
Fusion produces little waste. Helium
is the waste product.
Fission vs. Fusion
Fission
Fusion
 Splitting of a large
nuclei
 Nuclear power
plants
 Solid radioactive waste
 Atomic Bomb
 Joining 2 or more
smaller nuclei
 Sun and stars
 Very little waste
 Requires high temps to
maintain
 Hydrogen Bomb
Fission vs. Fusion Videoclip
Fusion Reactor
Tokamak
http://jammit.com.au/20080115/china-pins-big-14b-hopes-on-nuclear-fusion/
Nuclear Power Plants
1st plant in the US - Shippingport, PA in
1957
1st plant in the world Obninsk, Russia
in 1954
In the US, there are 104 units in 34
states to generates 20% of our
electricity.
Nuclear Power Plants
There are 5 plants in PA.
Limerick Generating Plant is the
closest nuclear power plant to NPHS.
Nuclear Plants with Operating License
Nuclear Power Plant Diagram
Nuclear Power Plant (Boiling Water
Reactor Plant)
Overall process at a nuclear power
plant:
Fission reaction → produces heat → to heat water
into steam →the stream drives turbines in a
generator → the generator produces electricity
Nuclear Reactors
The chain reaction of a fission
reaction takes place in the nuclear
reactor or reactor core.
The reactor is made up of a fuel, control
rods, a moderator, and a coolant.
US nuclear reactors are housed within a
concrete containment structure.
Fission Reaction: The fuel is U-235
 Nonfissionable uranium is U-238.
 Uranium ore (pitchblend) contains 0.7%
U-235.
 The enriched fuel is packed as pellets of 3%
U-235 and 97% U-238.
a centrifuge is used to enrich the fuel.
 Weapons-grade uranium is at least 90%
U-235.
Fission Reaction: The fuel is U-235
 The pellets are packed into long steel
cylinders called fuel rods that are 12-14
feet in length.
 Fuel rods are replaced every 24 months.
 Used fuel rods are known as spent fuel
rods.
Fuel Pellets
Nuclear Power Plants
Control Rods
Control rods are
used to absorb the
neutrons resulting
in slowing down or
stopping the chain
reaction.
View of fuel rods and control rods
immersed in water.
Nuclear Power Plants
Moderator
A moderator is used to slow down the
high-speed neutrons for more fission
reactions to occur.
A common material used as a moderator
is water.
Nuclear Power Plants
Cooling System
A cooling system is used to cool the
steam.
Water outside of the reactor is used to
cool the steam.
At Limerick Generating Plant, the cooled
water is discharged into the Schuykill River.
The cooled steam condenses into water
and is reused inside the reactor.
Water in the cooling tower does not
come in contact with the reactor core.
Nuclear Power Plant Diagram
Boiling-Water Reactor
Advantages of Nuclear Power Plants
Large amounts of energy
Low operating costs
No CO2 emissions to produce acid rain
Disadvantages of Nuclear Power
Plants
High construction costs
Waste from spent fuel rods
Safety
Location (NIMBY)
Nuclear Waste - Types
High-level nuclear waste is radioactive
waste products with high levels of
radioactivity.
Low-level nuclear waste is radioactive
waste products with low levels of
radioactivity.
Nuclear Waste - Sources
 High-level nuclear waste
Spent fuel rods
Military weapons
 Low-level nuclear waste
Nuclear laboratory protective clothing
Medical nuclear waste
Supplies from nuclear power plants
Nuclear Waste
Spent fuel rods are still highly
radioactive for thousands of years.
About 3,100 tons of commercial highlevel nuclear waste are produced
annually in the U.S.
There is no permanent storage place
for nuclear waste in the U.S.
Nuclear Waste
Federal law mandates the spent fuel
rods are stored on-site, usually in
steel-lined storage tanks or pools of
water.
Some plants are keeping the spent
fuel rods in dry cask concrete vaults
on the surface. (Limerick received
approval in 2007)
Nuclear Waste
 US government is developing a
permanent storage site in Yucca
Mountain in Nevada.
 The waste will be buried at least 1 km
below the surface in vaults.
 Progress for completion has been
delayed from 1998 to 2017 at the
earliest.
 Delays are due to legal, environmental,
and development concerns.
Yucca Mountain -
More than five miles of
tunnels, cross drifts and alcoves have been drilled.
Another 60 miles of tunnels branching off the main
one will store the hot waste.
http://blog.longnow.org/2002/03/03/yucca-mountains-future/
1.
2.
3.
4.
http://www.nrc.gov/waste/hlw-disposal/design.html
Canisters of waste,
sealed in special
casks, are shipped to
the site by truck or
train.
Shipping casks are
removed, and the
inner tube with the
waste is placed in a
steel, multilayered
storage container.
An automated system
sends storage
containers
underground to the
tunnels.
Containers are stored
along the tunnels, on
their side.
Entrance into Yucca Mountain
http://blog.longnow.org/2002/03/03/yucca-mountains-future/
Nuclear Accidents
Three-Mile Island
Date: March 28, 1979
Location: Susquehanna River near
Harrisburg, PA
Technical failures and human errors
lead to the worst nuclear accident in
U.S.
 https://www.youtube.com/watch?v=eGI7VymjSho
Three Mile Island
Nuclear Accidents - Chernobyl
 Date: April 26, 1986
 Location: northern Ukraine
 Flawed reactor design and inadequately
trained operators resulted in the worst
nuclear accident in the world.
 56 deaths to date due to radiation: 28
firefighters within 4 months with 19 later,
and 9 thyroid cancer deaths (4000 children
with thyroid cancer)
Map of Chernobyl
Nuclear Accidents
Fukushima Nuclear Power Plant, Japan
Date: March 11, 2011
Location: East Coast of Japan
A massive tsunami following a
major earthquake knocked out
power to the reactors, causing
multiple explosions and in some
cases, core meltdowns.