Topics for Today Ionizing Radiation and Human Health –Finish up Nuclear Fission –The 1 st...

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


– 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


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?


In 2005, Wisconsin used

24.6 THOUSAND TONS of coal for

energy production.


In 2005, Wisconsin used

24.6 THOUSAND TONS of coal for

energy production.

That’s 49,200,000 lbs

of coal!!


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


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



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?

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,


What does

the . mean?

In other words,


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


We left off here


What will H2O.+ most likely react

with?

.+

DNA Inside a Cell DNA Inside a Cell


What will H2O.+ most likely react

with?

Another water molecule!

H2O.+ + H2O .OH + H3O+

Unpaired electron Unpaired electron


This happens within FRACTIONS of a

second

H2O.+ + H2O .OH + H3O+


CAUTION

CAUTION

Are these chemical reactions or

nuclear reactions?


This happens within FRACTIONS of a

second

H2O.+ + H2O .OH + H3O+


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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