The Future

1
The Planet's Future
To nuke, or not to nukethat is the question!
Is nuclear power a renewable, or a non-renewable
energy source?
Comanche Peak Plant
2
Fusion and Fission
Matter can be changed into energy. Albert
Einstein, one of the greatest scientific minds of
the 20th century, discovered the mathematical
formula that explains this. It is
E MC2
Energy equals mass times the speed of light
squared.
3
Atoms and Nuclei

• Inside the nucleus

Helium
Protons and neutrons

• Outside the nucleus

Electrons
Proton
Neutron
Electron
As you can see, there are two neutrons, and two
protons in elemental helium in its most familiar
form
Now we know there are even smaller bodies called
quarks that make up nuclear particles.
4
Fission
An atoms nucleus can be split apart. When this
happens, a tremendous amount of energy is
released (NUCLEAR energy). Energy released is
both thermal and radiant.
Nuclear fission requires large nuclei from atoms
such as uranium, (fuel) which are then split into
two smaller nuclei of roughly equal size. When
this occurs, energy is released.

• Released slowly and controlled, it can be
  harnessed to generate electricity.

• Released quickly and all at once, it makes a
  colossal explosion also known as an atomic bomb.

5
Fission
A nuclear power plant like Comanche Peak uses
uranium as fuel.

• Uranium is an element with a naturally unstable
  nucleus.

• Uranium is mined and processed into pellets.

• The pellets are loaded into long rods and then
  into a fuel assembly

• The assemblies are then loaded into the reactor
  core, where the energy is produced

• The uranium atoms are split apart in a
  controlled chain reaction, giving off both heat
  light.

6
Control rods are used to keep the splitting
regulated so it doesnt get out of control.

• The chain reaction gives off thermal energy.

• The heat produced is used to boil water in the
  core of the reactor.

• This hot water is piped to another section of
  the plant, where it heats another set of pipes
  that are filled with water to make steam.

• The steam in this second set of pipes powers a
  turbine...

• The turbine spins the shaft connected to the
  generator which makes electricity...

Blah, blah, blah...
7
Danger of Reactors
Luckily, the conditions under which an atomic
bomb is created are not present in a nuclear
reactor.

• In bombs, almost pure pieces of Uranium-235 or
  Plutonium are held together with great force.
  Then, the particles are split in an UNCONTROLLED
  chain reaction

• Fission creates a radioactive material that is
  very harmful to the environment, if released.

Fission energy is now being used commercially in
the United States to produce about 20 of the
nation's electricity.
8
The two fissile materials we use that undergo
fission spontaneously are 235U and 239Pu
Strontium-90 mimics the properties of calcium and
is taken up by living organisms and deposited in
bones. It has the potential for causing cancer or
damaging the rapidly reproducing bone marrow
cells.
Strontium, cesium, and rubidium are the
radioisotopes which should be most closely
guarded against release into the environment.
They have half-lives of around 30 years, which
ensures that they are not only highly radioactive
but also be around for hundreds of years.
9
What do we do with our waste?
Highly radioactive waste from spent fuel is
vitrified or melted down with glass paste.

• This technique traps the radioactive atoms in a
  structure that is chemically stable for tens of
  thousands of years.

• The glass is poured into steel containers, which
  are temporarily stored in ventilation shafts to
  let the heat escape, since the waste is very hot.

• It must be allowed to cool for several decades
  before deep storage can be considered

• Then it must be confined for hundreds of
  thousands of years (the length of time necessary
  for its radioactive decay).

10
Fusion

• Fusion involves the fusing together of smaller
  nuclei to make a larger nucleus.

The sun uses nuclear fusion of the hydrogen
atoms, into the helium atom.
This process gives off heat, light, and other
radiation.
What types of energy do heat, and light represent?
Thermal and radiant
11
Atoms and Nuclei

• Inside the nucleus

Hydrogen
Protons and neutrons

• Outside the nucleus

Electrons
Proton
Electron
As you can see, there are no neutrons in
elemental hydrogen in its most familiar form
There are some forms of hydrogen, however, that
do contain neutrons.
12
Isotopes
Isotopes are elements that contain a different
number of neutrons than the most common average
of those elements found on Earth.
Hydrogen has two isotopes, called Deuterium, and
Tritium that are used as a fuel for fusion.
These two hydrogen isotopes each contain
neutrons, which the average hydrogen atom doesnt
containthereby making these heavier atoms than
normal.
How do you determine atomic mass?
Deuterium and Tritium, when found in the compound
H2O, make heavy water, because the atoms have a
greater mass than average hydrogen.
13
Deuterium and Tritium Two Hydrogen Isotopes
Since nuclei carry positive charges, they
normally repel one another. The higher the
temperature, the faster the atoms or nuclei move.
When they collide at these high speeds, they
overcome the force of repulsion of the positive
charges, and the nuclei fuse. In such collisions,
energy is released.
neutron
So, basically, two isotopes of hydrogen combine
to form a helium atom and an extra neutron, and
give off energy in the process.
proton
14
The Future and Problems faced by fusion
Scientists have been working very hard on the
development of nuclear fusion. They have had a
difficult time learning how to control the
reaction in a contained space.
The temperatures necessary to continue the
reaction (over 100 million degrees
C180,000,000 F) are difficult to reach and
contain.
The temperature on the suns surface is nearly
10,000 F, and at the core, nearly 27,000,000 F
due to the energy of fusion.
In a lab, scientists have been able to attain
temperatures as high as 3.6 billion degrees
Fquite a bit hotter than what is needed to
sustain reactions, but with difficulty.
The Plusses
The fuels used in fusion are nearly inexhaustible.
Fusion would be a cleaner source of energy, in
that the byproducts are not radioactive as with
the byproducts of fission.
15
Cold Fusion
Cold fusion is a hypothetical type of nuclear
reaction that would occur close to room
temperature. For the most part, it has been
rejected by the mainstream scientific community
because the original experimental results could
not be replicated consistently and reliably, and
because there is no accepted theoretical model of
cold fusion.