2. The world and how it reacts to nuclear energy LeAnna

3. Nuclear reactors create energy by nuclear fission, a process that splits the nucleus of an atom in two. An element with a heavy nucleus, most commonly uranium-235 (U-235), is hit by a free neutron. This divides the heavy nucleus into two lighter nuclei. The action of this split releases energy in the form of heat and radiation. Two to three other neutrons are released during this process. These neutrons then hit more U-235 nuclei and split them. This reaction continues on and on, forming what is called a chain reaction. Fission reaction diagram. Drawings courtesy of atomicarchive.com.atomicarchive.com Fission reactions fall into three categories, based on the speed of the reaction and the energy released. A reaction is subcritical, when on average, less than one of the free neutrons from each fission reaction hits another U-235 atom. This means that the fission reaction is below critical mass and will eventually die out.On average more than one of the neutrons hits another U-235 atom. For power generation, a critical reaction—the most stable type of reaction—must occur. This happens when on average exactly one of the neutrons from each fission reaction hits another U-235 atom. The fuel is at critical mass. It maintains a stable temperature, not explosively hot, and the reaction is not too slow to maintain fission in the fuel. The heat from the nuclear reaction converts water to steam. The steam turns turbines attached to generators, creating electricity. In a nuclear reactor, the reaction stays at critical mass through the use of devices to speed up or slow down the reaction as needed. What makes a nuclear reaction so useful for generating power is that it releases much more energy than the typical combustion reaction. For example, a coal plant produces about 1 kilowatt of electricity by burning 0.45 kg (1 lb) of coal. The fission of 0.45 kg of uranium produces about 3 million kilowatts.

5. This picture is showing the process of energy.

6. The pressurized water The boiling water reactorreactor

9. This power plant is being dismantled

11. In the future, we may develop fusion reactors for our electricity. Fusion is a nuclear reaction also.

12. This is a pressure vessel of the nuclear reactor showing how it connects to the turbine.

13. Complete diagram of the nuclear reactor, including the cooling towers.

14. The fuel is in long metal rods where fission takes place. Safety is an important factor in the design of nuclear reactors.

15. Nuclear power provides clean electricity at a very low cost, and it does not produce greenhouse gases. However, the reaction at the heart of nuclear power produces radioactive wastes. The potential danger from escaped radiation from an accident has given nuclear power a fearsome reputation. Since the near-disaster in 1979 at Three Mile Island, in the United States, and the terrible accident in 1986 at Chernobyl, Ukraine, nuclear-energy producers have taken great strides to make their plants safer. In a world where polluting emissions have become a bigger and bigger concern, nuclear power will be a significant piece of the energy- production puzzle.

16. Here is a complete animated diagram that includes the reactor vessel.

17. The End