 The most used substance for energy from fission is Uranium 235, but Plutonium 239 can also be used.  In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts, often producing free neutrons and lighter nuclei, which may eventually produce photons (in the form of gamma rays). Fission of heavy elements is an exothermic reaction which can release large amounts of energy both as electromagnetic radiation and as kinetic energy of the fragments (heating the bulk material where fission takes place). Fission is a form of nuclear transmutation because the resulting fragments are not the same element as the original atom.  Nuclear fission produces energy for nuclear power and to drive the explosion of nuclear weapons. Both uses are made possible because certain substances called nuclear fuels undergo fission when struck by free neutrons and in turn generate neutrons when they break apart. This makes possible a self-sustaining chain reaction that releases energy at a controlled rate in a nuclear reactor or at a very rapid uncontrolled rate in a nuclear weapon.  The amount of free energy contained in nuclear fuel is millions of times the amount of free energy contained in a similar mass of chemical fuel such as gasoline, making nuclear fission a very tempting source of energy; however, the products of nuclear fission are radioactive and remain so for significant amounts of time, giving rise to a nuclear waste problem. Concerns over nuclear waste accumulation and over the destructive potential of nuclear weapons may counterbalance the desirable qualities of fission as an energy source, and give rise to ongoing political debate over nuclear power.

 Fission products, that is lighter elements than the uranium or plutonium fuel, free neutrons, and gamma radiation. The net energy effect is a release of 200 Mev per fission.(Approx 3.2 x Joules)

▪ Nuclear power plants need less fuel than ones which burn fossil fuels. One ton of uranium produces more energy than is produced by several million tons of coal or several million barrels of oil.

 A control rod is a rod made of chemical elements capable of absorbing many neutrons without fissioning themselves. They are used in nuclear reactors to control the rate of fission of uranium and plutonium.

 How does a nuclear power plant produce electricity?  A nuclear power plant is basically a steam power plant that is fueled by a radioactive element, like uranium. The fuel is placed in a reactor and the individual atoms are allowed to split apart. The splitting process, known as fission, releases great amounts of energy. This energy is used to heat water until it turns to steam.  From here, the mechanics of a steam power plant take over. The steam pushes on turbines, which force coils of wire to interact with a magnetic field. This generates an electric current.  In a nuclear power plant, they use nuclear fission to heat up the water, the water from the nuclear core pass though a heat exchanger and heat up another water source that's separated from the core. That water then turn into steam, and the steam drive a turbine which in turn turns a generator to make electricity. I guess you can call it mechanical energy.

 Radiation  Harmful and contaminating waste products to the environment  Human error or machinery malfunction can result in a meltdown  Exposure to radioactive materials may cause human mutations e.g The incredible Hulk and babies born with like 3 legs and no arms etc etc etc

 Milestones in the History of Nuclear Energy  Amore in depth and detailed history of nuclear energy is on the nuclear past page.nuclear past page ▪ December 2, 1942: The Nuclear Age began at the University of Chicago when Enrico Fermi made a chain reaction in a pile of uranium. ▪ August 6, 1945: The United States dropped an atomic bomb on Hiroshima, Japan, killing over 100,000.atomic bomb ▪ August 9, 1945: The United States dropped an atomic bomb on Nagasaki, Japan, killing over 40,000.atomic bomb ▪ November 1, 1952: The first large version of the hydrogen bomb (thousands of times more powerful than the atomic bomb) was exploded by the United States for testing purposes.hydrogen bombatomic bomb ▪ February 21, 1956: The first major nuclear power plant opened in England.  Disadvantages of Nuclear Energy  The nations of the world now have more than enough nuclear bombs to kill every person on Earth. The two most powerful nations -- Russia and the United States -- have about 50,000 nuclear weapons between them. What if there were to be a nuclear war? What if terrorists got their hands on nuclear weapons? Or what if nuclear weapons were launched by accident? ▪ Nuclear explosions produce radiation. The nuclear radiation harms the cells of the body which can make people sick or even kill them. Illness can strike people years after their exposure to nuclear radiation.radiationsick ▪ One possible type of reactor disaster is known as a meltdown. In such an accident, the fission reaction goes out of control, leading to a nuclear explosion and the emission of great amounts of radiation. ▪ In 1979, the cooling system failed at the Three Mile Island nuclear reactor near Harrisburg, Pennsylvania. Radiation leaked, forcing tens of thousands of people to flee. The problem was solved minutes before a total meltdown would have occurred. Fortunately, there were no deaths.Three Mile Island nuclear reactor ▪ In 1986, a much worse disaster struck Russia's Chernobyl nuclear power plant. In this incident, a large amount of radiation escaped from the reactor. Hundreds of thousands of people were exposed to the radiation. Several dozen died within a few days. In the years to come, thousands more may die of cancers induced by the radiation.Chernobyl nuclear power plant ▪ Nuclear reactors also have waste disposal problems. Reactors produce nuclear waste products which emit dangerous radiation. Because they could kill people who touch them, they cannot be thrown away like ordinary garbage. Currently, many nuclear wastes are stored in special cooling pools at the nuclear reactors.nuclear waste ▪ The United States plans to move its nuclear waste to a remote underground dump by the year ▪ In 1957, at a dump site in Russia's Ural Mountains, several hundred miles from Moscow, buried nuclear wastes mysteriously exploded, killing dozens of people. ▪ Nuclear reactors only last for about forty to fifty years.  The Future of Nuclear Energy The Future  Some people think that nuclear energy is here to stay and we must learn to live with it. Others say that we should get rid of all nuclear weapons and power plants. Both sides have their cases as there are advantages and disadvantages to nuclear energy. Still others have opinions that fall somewhere in between.advantagesdisadvantages  Coal and oil burning plants pollute the air. Well-operated nuclear power plants do not release contaminants into the environment.