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Topics for Today
• Ionizing Radiation and Human Health– Finish up Nuclear Fission
– The 1st wartime atomic bomb
– Cell Damage
– Radiation Sickness
Readings for Today
• Hazards Associated with Radioactivity Section 7.8
• The DNA double Helix Section12.2
Topics for Friday
– Radiation Sickness
– Natural sources of radiation
– Quiz #3
Readings for Friday
• Hazards Associated with Radioactivity Section 7.8
Announcements
Radon Disks!
Are they in place?
Are they still there?
• Exam #1 NEXT Friday!
• Exams will be “multi-formatted”
Multiple Choice!
Problems!
Concept Questions!
Exams will be handed out as you enter the door
You will have until the end of the period to complete the exam
Exams will be handed out as you enter the door
You will have until the end of the period to complete the exam
I will be there starting at the beginning of the passing period,
8:35.
• As with quizzes…
Non-memory calculators
are OK
Please sit in dark colored
seats
Topics for Today
• Ionizing Radiation and Human Health– Finish Monday’s material
– The 1st wartime atomic bomb
– Cell Damage
– Radiation Sickness
Monday Review!
Nuclear Fission…
What’s in the Cloud?
WaterAlong with a lot earth, we find
“fallout”
What about the fission
products from a power plant?
Each cylinder contains 14 TONS of nuclear waste.
This waste is called “spent nuclear fuel” or (SNF).
These barrels contain fission byproducts, unfissioned U-235 and lots of U-238 and Pu-239.
Where did Pu-239 come from?
Remember, U-235 is only 3-5% of the
uranium in a nuclear power plant.
From Monday…
Remember, U-235 is only 3-5% of the
uranium in a nuclear power plant.
The rest of the uranium is mainly
U-238!
Review - Monday
What happens when a
neutron hits U-238?
238 92
239 92
10
U Un [
[
239 92U[
[Np
+
+ β0-1
239 93
Np239 93
Pu + β0-1
239 94
t1/2 = 2.4 days
t1/2 = 24,100 years
Is Pu-239 fissionabl
e?
238 92
239 92
10
U Un [
[
239 92U[
[Np
+
+ β0-1
239 93
Np239 93
Pu + β0-1
239 94
t1/2 = 2.4 days
t1/2 = 24,100 years
Is Pu-239 fissionabl
e?
Can current nuclear power plants use Pu-
239 for energy?
A “standard” nuclear reactor does not produce too much Pu-239.
Breeder Reactor…
• Simultaneously creates energy from U-235 and enriches the new fissionable fuel (Pu-239) from U-238.
CREATES more fissile fuel than we started with!!
These barrels contain fission byproducts, unfissioned U-235, lots of U-238, and some Pu-239.
Breeder reactors DRASTICALLY cut down on the
amount of nuclear waste…
The technology is here; do we
use them?
The technology is here; do we
use them?
We used to use them (1950s up
to 1977).
For fear of terrorists stealing the enriched nuclear fuel, President Carter banned the reprocessing of depleted fuels (1977).
For fear of terrorists stealing the enriched nuclear fuel, President Carter banned the reprocessing of depleted fuels (1977).
Likely linked to the Cold War politics.
And with current political
conditions…
This is what we are left with…
There are currently over 100 nuclear
power plants in the US
Which state has the most nuclear
reactors?
There are currently over 100 nuclear
power plants in the US
NOTE: No nuclear power plants in Alaska or Hawaii.
How much fuel is needed?
How much fuel is needed?
In 2005, Wisconsin used
24.6 THOUSAND TONS of coal for
energy production.
How much fuel is needed?
In 2005, Wisconsin used
24.6 THOUSAND TONS of coal for
energy production.
That’s 49,200,000 lbs
of coal!!
How much fuel is needed?
How much uranium would be
needed for the same energy output in WI?
For every 1 pound of uranium fuel, you need to burn about 18,400 pounds of coal to get the same energy output.
WI burned 49,200,000 lbs of coal in 2005
This would be 2,700 lbs of
uranium annually in WI
Topics for Today
• Ionizing Radiation and Human Health– The 1st wartime atomic bomb
– Cell Damage
– Radiation Sickness
HIROSHIMA
First wartime atomic bomb blast
August 6, 1945
Hiroshima was a city at work. The streets were filled. Children had reported to schools; it was a time when direct exposure in the open was at its peak…then, at 8:14 AM a prolonged and brilliant flash. Accompanying the flash of light was an instantaneous flash of heat traveling with the speed of light…duration probably less than one-tenth of a second, and its intensity sufficient to cause nearby things to burst into flames as far as four thousand yards from the hypocenter, with temperatures exceeding 1800 degrees Celsius…then a shock wave (Liebow 24).
http://www.artsci.wustl.edu/~copeland/atomicbomb.html
Initial Blast
• 1945 Population of Hiroshima = 300,000
• About 100,000 people were killed
Nearly every structure within one mile of ground zero was destroyed
Nearly every structure within one mile of ground zero was destroyed
Nearly every structure within one mile of ground zero was destroyed
US Dept of Energy
Within minutes after the blast, 9 out of 10 people half a mile or less from ground zero were dead.
US Dept of Energy
Of those who did survive….
• Several days after the blast, medical staff began to recognize the first symptoms of radiation sickness among the survivors
• Deaths from radiation sickness did not peak until three to four weeks after the attacks
• An estimated 30,000 extra deaths occurred within 4 months of the blast.
“The pain of war can not exceed the woe of aftermath”
Radiation Sickness“. . .survivors developed symptoms that puzzled doctors, such as blood cell abnormalities, high fevers, chronic fatigue, diarrhea, vomiting, hair loss, and depression.”
“Years later doctors noticed an increase in the incidence of cancer among the survivors. . .”
US Dept of Energy
3 days after Hiroshima…
Second wartime atomic bomb blast
Nagasaki, Japan
August 9, 1945
Video
This video was taken shortly after the bomb blast in Hiroshima…
Video
This video was taken shortly after the bomb blast in Hiroshima…
Full-length Video
After Hiroshima
When asked how he thought WWIII would be fought, Einstein replied
After Hiroshima
When asked how he thought WWIII would be fought, Einstein replied
“I don’t know how WWIII will be fought, but WWIV will be fought with sticks and stones.”
Why did the symptoms of
radiation sickness take 1-2 weeks to
manifest?
What was in the “black rain”?
Akijiro Yashima3,700 m from the hypocenter
Review – Nuclear Fallout
What is nuclear fallout?
What is nuclear fallout composed of?
Is it radioactiv
e?
How does radioactivity
affect people?
Is anyone IMMUNE to
the effects of radioactivity?
Review – Nuclear Fallout
What is nuclear fallout?
What is nuclear fallout composed of?
Is it radioactiv
e?
How does radioactivity
affect people?
Is anyone IMMUNE to
the effects of radioactivity?
H2O
Ionizing radiation(alpha, beta, or gamma)
REVIEW
Why water?
1. Water can range from 45-75 % of your body mass
1. Depends on your sex and body structure
2. Gamma rays are more likely to interact with water molecules than fats, lipid, proteins, etc…
H2
O
++
+electron
H2
O
H2O
++
Ionizing radiation +e-
In other words,
H2O H2O.+ + e– Ionizing radiation
In other words,
H2O H2O.+ + e– Ionizing radiation
What does
the . mean?
In other words,
H2O H2O.+ + e– Ionizing radiation
What does
the . mean?
H2O.+ is a free radical
A free radical is any atom or molecule or ion with an unpaired electron.
A free radical is any atom or molecule or ion with an unpaired electron.
Free radicals (as we will soon see) are often VERY
reactive.
We left off here
H2O H2O.+ + e– Ionizing radiation
We left off here
H2O H2O.+ + e– Ionizing radiation
What will H2O.+ most likely react
with?
We left off here
H2O H2O.+ + e– Ionizing radiation
What will H2O.+ most likely react
with?
.+
DNA Inside a Cell DNA Inside a Cell
H2O H2O.+ + e– Ionizing radiation
What will H2O.+ most likely react
with?
Another water molecule!
H2O.+ + H2O .OH + H3O+
Unpaired electron Unpaired electron
H2O H2O.+ + e– Ionizing radiation
This happens within FRACTIONS of a
second
H2O.+ + H2O .OH + H3O+
Unpaired electron Unpaired electron
CAUTION
CAUTION
Are these chemical reactions or
nuclear reactions?
H2O H2O.+ + e– Ionizing radiation
This happens within FRACTIONS of a
second
H2O.+ + H2O .OH + H3O+
Unpaired electron Unpaired electron
Another free radical…
.OH is the hydroxyl radical
.OH will react with just about anything.
Another free radical…
.OH is the hydroxyl radical
.OH will react with just about anything.
.OH does not discriminate
between molecules
Figure 12.8
Including our DNA
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