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Nuclear Energy. Nuclear Energy. Nuclear energy – energy that exists within the nucleus of an atom Nuclear fission – bonds which hold the nucleus together are broken, which releases huge amounts of energy. Nuclear fission. Neutrons strikes a Uranium-235 nucleus
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Nuclear Energy • Nuclear energy – energy that exists within the nucleus of an atom • Nuclear fission – bonds which hold the nucleus together are broken, which releases huge amounts of energy
Nuclear fission • Neutrons strikes a Uranium-235 nucleus • The nucleus splits and releases energy and more neutrons which strike more Uranium-235 nuclei in a chain reaction
How a nuclear power plant works • Energy from nuclear reactions heats and boils water • Superheated water creates high-pressure steam • Steam drives an electric generator which creates electricity
Advantages of nuclear energy • 1 gram of Uranium-235 delivers the same energy as 3.5 metric tons of coal • Well designed reactors can run for years without having to be refueled or shut down • Doesn’t produce harmful gases like carbon dioxide
Nuclear Energy Disadvantages
Disadvantages of nuclear energy • Radioactive waste • No facility for permanent disposal of waste – each plant has its own temporary storage facility • Short supply of Urnaium-235 • 100-200 year supply (Not a renewable resource) • Extremely expensive • Plants are large, complex and expensive to build and maintain
Safety Concerns • Heat from nuclear fission reactions can destroy the building and release radioactive products into the air
Nuclear Power Plant Accidents • Chernobyl – 1986 • Worst nuclear power plant accident until Fukushima in 2011. • An unauthorized test was conducted while safety devices were turned off
Chernobyl • Explosions and fireball destroyed part of the plant • 30 people died during the accident but about 2,500 people contracted cancer from the radiation
Three Mile Island • Worst nuclear accident in U.S. • Occurred in Middletown, PA on March 28, 1979 • Only a small amount of radioactive gas escaped
Fukushima Daiichi Nuclear disaster • March 11, 2011 a 9.0 magnitude earthquake rocked Japan and resulted in a 14m (46’) tsunami that hit the coast where the Fukushima reactor was located. • The containment unit and tsunami wall were only designed to withstand a 5.7m (19’) tsunami. • The reactors shut down, but the generators that power the cooling pumps got inundated with salt water and shorted out. • A partial meltdown occurred in 3 of the reactors and explosions blew apart the primary containment vessels and exposed spent fuel pools.
Another form of Nuclear Energy: Nuclear Fusion • Small nuclei combine to form a larger nucleus and release huge amounts of energy • Opposite of nuclear fission • Potentially safer than nuclear fission but not practical due to the very specific conditions