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Homer: "Where are we going, sir?" Burns: "To create a new and better world." Homer: "If it's on

Homer: "Where are we going, sir?" Burns: "To create a new and better world." Homer: "If it's on the way, could you drop me off at my house?" . History of Nuclear Power. James Chadwick first identified free neutrons in 1932.

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Homer: "Where are we going, sir?" Burns: "To create a new and better world." Homer: "If it's on

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  1. Homer: "Where are we going, sir?"Burns: "To create a new and better world."Homer: "If it's on the way, could you drop me off at my house?"

  2. History of Nuclear Power • James Chadwick first identified free neutrons in 1932. • These neutrons were relatively heavy and able to plough through electrons surrounding the nucleus of other atoms • Neutrons are electrically neutral and are not deflected by positive nuclear charge

  3. Enrico Fermi • Physicist who studied nuclear physics • Discovered that firing these free neutrons at elements caused them to become radioactive and emmit β-particles

  4. Discovery of Nuclear Fission • 1939 –Lise Meitner and Otto Frisch proposed that the splitting of a heavy nucleus by way of absorbing a neutron, caused the atom to become unstable and split into two lighter nuclei. • This process was called Nuclear Fission and they observed that this reaction released a great deal of energy.

  5. Nuclear Fission • Fermi later discovered that the fission reaction might release free neutrons which could cause further fission reactions • A chain reaction could occur releasing a great deal of energy in a short time, a nuclear explosion.

  6. Enrichment • Niels Bohr was the first to establish that the U-235 isotope readily underwent fission, but the U-235 isotope is “diluted” in natural uranium by 140 atoms of U-238 • Enrichment was a way to increase the proportion of U-235 and aid in the chain reaction.

  7. Manhattan Project • 1941- President Roosevelt put resources into the development of the “atomic bomb” • This lead to further studies of nuclear fission and the discovery of the first controlled chain reaction. achieved by Fermi and a group of scientists at the University of Chicago

  8. Small Steps Toward Power Production • December 20, 1951 – experimental reactor produced enough power to light four 150 watt light bulbs • July 17, 1955 - Argonne Lab designed first reactor to provide power for an entire town (Arco, Idaho). • 1957 - The Atomic Energy Commission sponsored a 60 megawatt breeder reactor plant in Shippingport, PA.

  9. First Commercial Power Plant • 1959 – Dresden Unit One was built at a cost of $18 million in Morris, Illinois. • 200 MW Duel Cycle Boiling Water Reactor • Designed and operated by General Electric until 1979 when it was shut down.

  10. Nuclear Fission “A mechanism by which a heavy nucleus absorbing a neutron might become unstable and split into two lighter nuclei.” Source: Energy Systems & Sustainability

  11. Inducing Fission • Absorption of a free Neutron • free protons / other nuclei can also induce fission • Easiest in Heavy elements • fission in elements heavier than Fe  Output E • fission in elements lighter than Fe  Input E • Abundance / Easy of Fission: • Uranium heaviest naturally occurring element • Plutonium undergoes spontaneous fission Source: How Stuff Works

  12. Chain Reaction • Initiation  2 or more neutrons  neutrons escape/initiate more fission. • High Concentration of U-235 required to maintain chain reaction Animation of Fission & Chain Reaction Source: ThinkQuest ‘98

  13. Critical Mass-The amount of material of a given shape and volume to maintain a chain reaction Source: Energy systems & sustainability

  14. Products of Fission • 2 new radioactive nuclei • 2 or 3 free neutrons • Heat / Gamma Radiation • ENERGY Source: Nuclear Fission and Nuclear Fusion

  15. Where does the Energy come from? • Sum of Mass of products < Original Mass • “Missing” Mass (~0.1% of Original Mass) has been converted to energy • E=Δmc^2 • U235 + n → fission + 2 or 3 n + 200 MeV Source: Think Quest

  16. E=Δmc^2 • A very small amount of matter is equivalent to a vast amount of energy.  • For example, 1 kg (2.2 lb) of matter converted completely into energy would be equivalent to the energy released by exploding 22 megatons of TNT. Source: Nuclear Fission and Nuclear Fusion

  17. Nuclear Fusion • “the comming together of two lighter nuclei to form one heavier one • Process that powers the stars • Original source of almost all of earths energy Source: Joint European Torus (JET)

  18. How Fusion works • Most suitable reaction involves: • Deuterium (D) • Tritium (T) (Isotopes of Hydrogen) • Temperatures of >10 million deg. C • Plasma: State in which electrons have been removed from atomic nuclei Nuclear Fusion Animation Source: Joint European Torus (JET)

  19. Means of Initiating Fusion: Source: FusEdWeb: Fusion Energy Educational Web Site

  20. Fusion by Magnetic Confinement • PLASMA is so high in energy it requires Magnetic Fields to contain it. • Magnetic fields trap superheated fusion fuel in center of loop. • Immense temperatures/pressures Source: FusEdWeb: Fusion Energy Educational Web Site http://fusedweb.pppl.gov/

  21. Why does Fusion yield Energy? • Mass of Products is less than mass of reactants. • E=mc^2 • mass converted to kinetic energy Source: FusEdWeb: Fusion Energy Educational Web Site

  22. Tritium: Bombarding Lithium with a Neutron Deuterium: Plentiful in ordinary water. 1/6500 hydrogen atoms in water is Deuterium 1 gallon of water conceivably has the energy content of 300 gallons of gasoline Where does Tritium & Deuterium Come from? Source: General Atomics http://fusedweb.pppl.gov/

  23. Yield of Fission vs. Fusion Source: General Atomics

  24. Nuclear Fuel Cycle

  25. Reactor Core

  26. Moderators • Slows the neutrons in order to maintain chain reaction

  27. Light Water Moderator • Ordinary Water • light-water reactors require slightly enriched (up to 20% U-235) uranium fuel to sustain the fission reaction. • 4/5 of today’s reactors are light water • Reactor Types: Boiling and Pressurized Water

  28. Pressurized Water Reactor

  29. Boiling Water Reactor

  30. Heavy Water Moderator • Hydrogen-2 or Deuterium (D20) • Uses Natural Uranium as oppose to Enriched uranium • isolating the small amount of D2O present in natural water requires considerable amounts of electricity. • Reactor Types: CANDU and Steam Generating Heavy Water Reactor

  31. Graphite Moderator • Most Easily Available Effective Moderator • Derived from Carbon(graphite) • Heavier than the Deuteron but neutron absorption low • Reactor Types: Advance Gas Cooled Reactor

  32. Spent Fuel • 2 Distinct Processes: • Direct Disposal • Reprocessing

  33. Consumption • Nuclear power provides about 6% of the worlds primary energy. • 439 Total Reactors in 31 different countries. • 103 in the US • 59 in France • 53 in Japan • Three countries receive more than half of their electricity from nuclear: France, Lithuania, Belgium. • US gets 20% of electricity from nuclear

  34. Pros Abundant Reliable Relatively safe Little pollution Radiation

  35. Cons Meltdowns – lack of coolant in the core Waste Disposal- high and low level Radiation- weak carcinogen

  36. Radioactivity: Pro and Con • Did you know that some of the foods we eat have been treated by exposure to radiation? • Have you ever wondered how we know the age of dinosaur bones? • Have you ever known anyone who was treated for cancer with radiation therapy? • Have you ever wondered how a nuclear submarine is powered? • Have you ever had an x-ray to look for a broken bone?

  37. Environmental Effects Radioactivity Waste heat Sulfur Dioxide Air quality

  38. Nuclear Efficiency Nuclear power plants need to be re-fueled only once every year, while coal power plants require a trainload of coal per day. The energy that can be obtained from one pound of uranium is equal to the amount of energy in approximately million pounds of coal.

  39. Benefits of Nuclear Energy • Nuclear power is the only energy producing technology which takes full responsibility for all its wastes and fully costs this in the the product. • The amount of radioactive wastes are very small relative to wastes produced by fossil fuels . • Spent nuclear fuel may be treated as a resource.

  40. Uranium Resources Known Recoverable Resources* of Uranium tonnes U percentage of world Australia 863,000 28% Kazakhstan 472,000 15% Canada 437,000 14% South Africa 298,000 10% Namibia 235,000 8% Brazil 197,000 6% Russian Fed. 131,000 4% USA 104,000 3% Uzbekistan 103,000 3% World total ,107,000 * Reasonably Assured Resources plus Estimated Additional Resources - category 1, to US$ 80/kg U, 1/1/01, from OECD NEA & IAEA, Uranium 2001: Resources, Production and Demand.Brazil, Kazakhstan and Russian figures above are 75% of totals.

  41. Uranium Availability

  42. Greenhouse Gas Emissions • Worldwide emissions of CO2 from burning fossil fuels total about 25 billion tonnes per year. About 38% of this is from coal and about 43% from oil. If uranium is used in a nuclear power reactor, these emissions do not occur.

  43. Fuel Immediate fatalities 1970-92 Who? Deaths per TWy* electricity Coal 6400 workers 342 Natural gas 1200 workers & public 85 Hydro 4000 public 883 Nuclear 31 workers 8 Safety Factor

  44. References • “Basic Nuclear Fission.” ThinkQuest. Accessed from: http://library.thinkquest.org/17940/texts/fission/fission.html?tqskip1=1. on 2-13-05. • General Atomics. FusEdWeb: Fusion Energy Educational Web Site. accessed from: http://fusedweb.pppl.gov/. on 2-13-05. • Godfrey Boyle, Bob Everett, Janet Ramage. Energy Systems and Sustainability. Oxfoord University Press 1998. • How Stuff Works. “How Nuclear Power Works.” Accessed from: http://people.howstuffworks.com/nuclear-power2.htm. on 2-13-05. • “Nuclear Fission and Nuclear Fusion.” Accessed from:http://chemed.chem.purdue.edu/genchem/ topicreview/bp/ch23/fission.html. on 2-13-05. • http://www.chem.duke.edu/~jds/cruise_chem/nuclear/pros.html • http://starfire.ne.uiuc.edu/~ne201/1996/kopke/problems.html • http://members.tripod.com/funk_phenomenon/nuclear/procon.htm • http://www.world-nuclear.org/info/inf69.htm • http://nuclearhistory.tripod.com/history.html • www.chemcases.com

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