History of Fission and Fusion
In an atom’s nuclei, changes can occur in the structure of the atom. These changes are called nuclear reactions. In some nuclear reactions, a large amount of energy escapes. This energy is called nuclear or atomic energy. Most nuclear energy is produced naturally (the sun and stars), but since the early 1940’s, man has been able to harness the power of the atom and create man-made nuclear energy.
There are two ways to start a nuclear reaction, the first and the easiest, is fission. Fission is the process of splitting a large, unstable atom into two smaller atoms, by adding a neutron to the unstable atom. When the neutron is added, the atom becomes unstable and splits in two; releasing the energy that was used to hold it together. Prior to the mid 1930’s, it was considered impossible to split an atom (the word atom comes from the Greek word atamos meaning indivisible), however, since the invention of the cyclotron, it has been possible. The cyclotron, or particle-smasher, is a machine that speeds up protons. The first cyclotron was a collection of tubes that went around in a circle and at precise instances would give a jolt of electricity to the proton, which was spinning around the track in a magnetic field. The inventor of the cyclotron, Ernest Lawrence, found that if the proton was in a magnetic field, it would take the same amount of time to go all the way around the circle no matter how big it was. By the time the proton had completed one loop, it had sufficient speed to split open a nucleus.
The second way to start a nuclear reaction, is fusion. Fusion is exactly what is sounds like, the fusing of two atoms together. Due to the internal forces acting on the nucleus, this reaction cannot be obtained just by applying pressure on the atoms. It takes not only an incredible amount of pressure, but an immense temperature, on the order of 15,000,000ºK. These two factors make replicating this reaction, in a controlled fashion, very difficult here on earth.
Testing The First Nuclear Reactor
Art courtesy of
http://www.icjt.org
Soon after the cyclotron was
invented, the Manhattan Project was started. As I am sure many of you know,
the Manhattan Project was started to construct the first atom bomb. In 1942,
President Roosevelt ordered the Army to build an atom bomb; this was because
at the time, Germany was working on her own atom bomb. Brigadier General
Leslie R. Groves was placed in command of (a seemingly impossible task)
creating the most powerful bomb the world had ever seen in only a few years,
and had to do it all in total secrecy. In a run down boys school in
New Mexico, the world’s first atom bomb would be developed. The site for
producing the U-235 (the fuel for the bomb) was chosen in the hill country
of Tennessee, in a region called Back Oak Ridge. In return for such a tight
timeline for the project, the government gave the scientists a blank check
to develop the “Bomb”. Three years, and millions of calculations later, the
first bomb, which, was code named “Trinity” was detonated in the desert of
New Mexico. This, however, was not good enough for these scientists.
Even before they finished the first atom bomb, they were thinking of
building an even more powerful bomb. This bomb was finished in 1952 and
“Super” became the world’s first thermonuclear bomb.