Nuclear Reactions

When the atoms of certain elements, including uranium and plutonium, are split, energy is released. The process in which the atom is broken apart is called fission. Fission creates a chain reaction in which additional atoms are also split, resulting in a huge release of energy. Early nuclear weapons, like the atomic bombs dropped on Japan at the end of World War II, used uranium and plutonium as fissionable materials. Since the 1950s, newer weapons also use fusion, a process in which atoms are combined to create even more powerful nuclear reactions. For all nuclear weapons, dangerous radiation is released when the fission or fusion reaction occurs.