When nuclear reactions were first discovered in the 1930s, many scientists doubted they would ever have any practical application. But the successful initiation of the first controlled reaction at the University of Chicago in 1942 quickly changed their views.

In the first controlled nuclear reaction, scientists discovered a source of energy greater than anyone had previously imagined possible. They discovered that the nuclei of uranium isotopes could be split, thus releasing tremendous energy. The reaction occurred when the nuclei of certain isotopes of uranium were struck and split by neutrons. This is now known as nuclear fission, and the fission reaction results in the formation of three types of products: energy, neutrons, and smaller nuclei about half the size of the original uranium nucleus.

Neutrons are actually produced in a fission reaction, and this fact is critical for energy production. The release of neutrons in a fission...