Nuclear Fusion

1. Nuclear Fusion
By Jason Beedle

2. Nuclear Fusion is the reaction that makes the Universe shine and lights up
all of the stars including the one we are most familiar with, the sun. Nuclear Fusion is
the process that mainly converts Hydrogen into Helium. This produces a tremendous
amount of energy in the form of light and heat. The conversion of Hydrogen and
Helium is the reaction that makes almost all life on Earth possible.

3. This is a diagram of This produces a
the Proton-Proton Gamma Ray and
chain reaction forms a light helium
which is the major atom, which is
reactions that designated as 3He.
make fusion Two 3He’s then join
possible. As you together and
can see on the produce two 1H
right this reaction atoms and form a
requires four regular helium
hydrogen atoms. atom which has two
At the beginning neutrons and two
two hydrogen protons. The end
atoms or 1H product, the helium
combine and atom, is actually
produce one less massive than
positron and one the four hydrogen
neutrino and then atom’s added
form a heavy masses. This loss in
hydrogen atom or mass is converted
a 2H atom which into the light and
has a neutron in it. heat that make
After this another stars shine through
1H atom is joined the equation
to the 2H atom. E=MC2.

4. The Proton-proton chain as explained on the other
page is a wonderful way to make energy, but the
conditions have to be just right to make this reaction
happen. For one, the temperatures have to be
incredibly high, as high as 15.7 million Kelvin and the
reaction requires high amounts of pressure. This
reaction also requires huge amounts of hydrogen
atoms. This makes it rather hard to initiate this
process on Earth , but the one place in the universe
that fusion is achieved with ease is the center of a star
like our sun.

5. The Sun is a main sequence, G2 class star.
This means that the sun is middle aged
which means that it is about 5 billion years
old and has an expected life spanned of
about 10 billion years. Also contrary to the
pictures of the sun, it is actually a yellow
dwarf star. In the picture on the left , the
core is visible in the very center of the star,
this is where 99% of the sun’s energy is
generated. In one second the sun uses 620
million metric tons hydrogen to fuel the
fusion reaction.

6. In other Stars
Hydrogen is the most abundant element
in the space and makes up about 90% of
the weight of universe. Most of this
hydrogen is in expansive clouds that are
remnants of stars that went supernova. A
lot of hydrogen is also being burned
inside of stars to create heat and light.
Most stars use the proton-proton chain
reaction to make their energy for most of
their lives, but when they run out of
hydrogen they start to fuse other
elements, such as Helium, Carbon,
Oxygen, Silicon and other elements until
it reaches Iron which is designated as Fe
on the diagram to the left.
Once the star reaches Iron, it cannot fuse it with out a net loss of energy, but the star
tries to ignite the fusion by collapsing and it keeps getting smaller and smaller until
the collapsing layers hit the core of the star and explosively rebound creating a
supernova. This usually only happens with a star that has a much greater mass than
the sun. The core of these stars then either turn into a Neutron star or a Black hole
depending on how massive the star was.

7. Fusion in Our World
There are really two different uses of fusion in our world
today: as a power source and as a weapon.
Scientists and engineers have been trying for years to
achieve a Fusion reactor. The picture on the right shows one
of the largest prototype reactors in the world and is located
in France. It is called JET which stands for Joint European
Torus and it has now produced 16 megawatts of fusion
power. It is the largest magnetic confinement fusion
research facility in the world and is built in the tokamak
design. The tokamak design uses magnetic fields to contain
super hot plasma that contains the hydrogen. There are also
several other designs like Inertial confinement fusion which
uses lasers to ignite a pellet of hydrogen and create fusion.
Nuclear fusion is also used in making weapons of mass
destruction such as the Hydrogen bomb, otherwise known as
the H-bomb. These H-bombs are over 450 times more
powerful than the bomb dropped on Nagasaki. Most modern
H-bombs use lithium deuteride as their fusion fuel, but older
H-bombs actually used liquefied deuterium, otherwise
known as heavy hydrogen for fuel.

8. Sources:
http://en.wikipedia.org/wiki/Nuclear_fusion.
Nuclear Fusion - Wikipedia. Access date
11/10/12.
http://www.ccfe.ac.uk/introduction.aspx.
Fusion Energy - CCFE. Access date 11/11/12
http://physics.info/fusion/: Fusion – The
Physics Hypertextbook. Access date 11/12/12