Although nuclear power is in general a clean source of power in terms of the environment, there are many things that can go wrong with it. One is human error such as Chernobyl, another the waste products, and other the mining of uranium. Uranium mining is not always a clean or good for the environment as it should be, and since uranium is used as fuel in nuclear fission it is necessary for the reactor. Another problem is that the waste products of nuclear reactors are very toxic and will be so for a long time. This means that it�s really dangerous to transport them from one place to another. These problems combined with the amount of human error are a large safety problem for nuclear reactors as a source of power.
In 1942 Enrico Fermi built the worlds first nuclear reactor in Chicago. It had control rods as well as graphite bricks for control. Enrico Fermi was an Italian who had fled to Columbia University in New York City to escape fascist rule in Italy in the 1930s. He also came up with the equation 235/92-U + 1/0 n + 139/56-Ba + 94/36-Kr + 3 1/0 n which is the formula for the nuclear reaction, fission, and was used in the making of the atomic bomb. During this time Neils Bohr had also come up with a similar theory about nuclear fission, and it was suggested that Einstein write a letter to President Roosevelt, which he did, indicating the military concerns. This sparked the �Manhattan Project� which produced the atomic bomb. When Fermi came to the US he tried to create atoms that were heavier then the heaviest known element, which at the time was Uranium. He did this through was is now called nuclear fission. He also discovered that graphite could be used to absorb some of the energy of the neutrons in the chain reaction, thus slowing down and controlling the process.
