The Committee on Science and Technology of the United States House of Representatives provided the following information before its Apr. 23, 2008 hearing “Opportunities and Challenges for Nuclear Power,” published on www.science.house.gov:
Nuclear Power Plant image from OSHA website of the US Dept. of Labor (accessed Dec. 2, 2008)
"Nuclear power is derived from energy that is released when relatively large atoms are split in a series of controlled nuclear reactions. The resulting heat is used to boil water which drives a steam turbine to generate electricity. The process of splitting an atom is known as nuclear fission. Nuclear power represents approximately 20 percent of the total electric generating capacity in the U.S. with 104 nuclear plants currently operating.”
The Nuclear Energy Institute stated the following in its fact sheet “How Nuclear Plants Generate Electricity,” published on www.nei.org (accessed Nov. 26, 2008):
“Nuclear plants, like plants that burn coal, oil and natural gas, produce electricity by boiling water into steam. This steam then turns turbines to produce electricity. The difference is that nuclear plants do not burn anything. Instead, they use uranium fuel, consisting of solid ceramic pellets, to produce electricity through a process called fission.
Nuclear power plants obtain the heat needed to produce steam through a physical process. This process, called fission, entails the splitting of atoms of uranium in a nuclear reactor. The uranium fuel consists of small, hard ceramic pellets that are packaged into long, vertical tubes. Bundles of this fuel are inserted into the reactor.”
The US Department of Energy Office of Nuclear Energy, Science and Technology
wrote the following in its study “The History of Nuclear Energy,” published on www.ne.doe.gov (accessed Nov. 26, 2008):
“Although they are tiny, atoms have a large amount of energy holding their nuclei together. Certain isotopes of some elements can be split and will release part of their energy as heat. This splitting is called fission. The heat released in fission can be used to help generate electricity in powerplants.
Uranium-235 (U-235) is one of the isotopes that fissions easily. During fission, U-235 atoms absorb loose neutrons. This causes U-235 to become unstable and split into two light atoms called fission products.
The combined mass of the fission products is less than that of the original U-235. The reduction occurs because some of the matter changes into energy. The energy is released as heat…
A series of fissions is called a chain reaction. If enough uranium is brought together under the right conditions, a continuous chain reaction occurs. This is called a self-sustaining chain reaction. A self-sustaining chain reaction creates a great deal of heat, which can be used to help generate electricity.
Nuclear power plants generate electricity like any other steam-electric power plant. Water is heated, and steam from the boiling water turns turbines and generates electricity. The main difference in the various types of steam-electric plants is the heat source. Heat from a self sustaining chain reaction boils the water in a nuclear power plant.”
John Deutch, PhD, Professor of Chemistry at the Massachusetts Instiutute of Technology (MIT), and Ernest J. Moniz, PhD, Director of Energy Studies at the MIT Laboratory for Energy and the Environment, et al., wrote the following in the 2003 MIT interdisciplinary study “The Future of Nuclear Power,” published at www.web.mit.edu:
“The nuclear fuel cycle consists of the steps required to produce nuclear power, including the input of fissile material, the processes that convert raw material to useful forms, the outputs of energy, and the treatment and/or disposition of spent fuel and various waste streams…
Fission image from the Oxford Illustrated Science Encyclopedia (accessed Dec. 2, 2008)
At the heart of the nuclear fuel cycle is the nuclear reactor that generates energy through the fission, or splitting, of uranium and plutonium isotopes...
The fission process is caused by neutrons in the reactor core and both liberates considerable energy and produces more neutrons. The energy released is 1 million watt-days per gram of U-235 that undergoes fission, equivalent to 2.5 million times the energy released in burning one gram of coal.
The produced neutrons can in turn yield additional fission events, producing a chain reaction that sustains energy production. The probability for a neutron to cause a fission is very high for certain isotopes (in particular, U-235 and Pu-239) when the neutrons are slowed down, or moderated, with respect to the relatively high energy they possess when produced by fission. In a light water reactor (LWR), the moderation is accomplished rapidly by collision of the neutrons with hydrogen nuclei (protons) in the water molecule.”