Nuclear Energy In a universe law, energy and matter have a common origin. None the energy nor the matter can be created or destroy, instead they just change their state. As well, they are convertible to each other. Albert Einstein was the first man explained this relation by the well know formula: E= mC2  This equation defines: E (Energy) equals to m(mass) times C2 (C stands for speed of light). By looking in close, you may find the enormous energy exist in a small piece of material. The name of atom comes from Greek language, referring to smallest part of nature. Nowadays we have a better knowledge on atom structure, and we know a nucleus, surrounded by electrons, form the atoms. This structure is somehow similar to our solar system.  Nuclear Fission Any try for splitting a part a nucleus will cause a tremendous energy be released. This energy would be released in both forms of heat and light. In a harnessed, controlled way of doing this, a useful energy for producing electricity is possible. Doing this at once would result to a big explosion, as seen in an automatic bomb. In a nuclear power plant, uranium is the element used as fuel. Uranium is found in many parts of the world but in a low quantity. It is loaded in to the reactor in a tiny pallet form inside long rods. Fission meaning splitting a part is what happens in a reactor. Here uranium atoms are split in a paced controlled chain of reactions. Inside a reactor the intensity of crashes are harnessed by inserting-taking of control roads. In an atomic bomb a different process occurs, by using almost pure pieces of elements-uranium 235 or plutonium, in a precise mass and shape, burning them together in a great force. As you see there is no requisite like this in a reactor. Byproducts of such reactions are radioactive materials. If released, they would be gravely harmful. Knowing this, strong structures must keep the materials in the case of any accident. The released heat energy would be used for boiling water in the core of reactor. So instead of burning fuel, we may use the heat of reactor core. By sending the hot water around the nuclear to the heat exchanger section, water filled pipes produce steam needed for steam turbine.  Nuclear Fusion In another form of nuclear reaction, joining of smaller nuclei makes a larger nucleus. Such a process in sun changes the hydrogen atoms to helium. The result is a mass a heat and light we receive in earth. In a more detailed explanation, two different types of atoms, deuterium and tritium, combine to make a helium plus and extra particle called neutron. There has been a fierce competition among scientists, but to their frustration, they have yet trouble in controlling reaction in a closed space. The advantage of fusion is its abundance of supply (hydrogen) as well as its less radioactive material than fission.