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Nuclear Energy

Nuclear Energy. E = mc 2. E: energy m: mass c: speed of light c = 3 x 10 8 m/s. E = mc 2. Mass can be converted to energy Energy can be converted to mass Mass and energy are the same thing The total amount of mass plus energy in the universe is constant.

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Nuclear Energy

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  1. Nuclear Energy

  2. E = mc2 E: energy m: mass c: speed of light c = 3 x 108 m/s

  3. E = mc2 • Mass can be converted to energy • Energy can be converted to mass • Mass and energy are the same thing • The total amount of mass plus energy in the universe is constant

  4. Mass Defect of Alpha Particle Mass difference = 0.0304 u Binding energy = 28.3 MeV Fusion product has less mass than the sum of the parts.

  5. Nuclear Mass vs Atomic Number is NOT Linear

  6. Mass/Nucleon vs Atomic Number Fusion Fission

  7. Binding Energy/Nucleon vs Number of Nucleons

  8. Mass Defect in Fission • When a heavy element (one beyond Fe) fissions, the resulting products have a combined mass which is less than that of the original nucleus.

  9. U-235 – Neutron Bombardment

  10. U-235 -- Fissile

  11. Possible U-235 Fission

  12. How Stuff Works Site • Visit the How Stuff Works Site to learn more details about nuclear energy

  13. Chain Reaction

  14. Abundance of U-235

  15. Plutonium Production

  16. U-238 – Not Fissile

  17. Breeder Reaction

  18. Breeder Reactor • Small amounts of Pu-239 combined with U-238 • Fission of Pu frees neutrons • These neutrons bombard U-238 and produce more Pu-239 in addition to energy

  19. Plutonium • Plutonium is fissile • Half-life of Plutonium is 24,000 years • Plutonium can be chemically separated from uranium – easier than separating U-235 from U-238 • Plutonium is chemically poisonous (just like lead and arsenic)

  20. Plutonium • Plutonium attacks the nervous system and can cause paralysis (or death in sufficient doses) • Plutonium combines rapidly with oxygen to form compounds which are chemically biologically harmless • Plutonium is always radioactively toxic – worse than uranium but not as bad as radium • Plutonium emits high energy alphas which kill cells • Greatest danger – nuclear fission bombs

  21. Einstein Prediction • "I do not know with what weapons World War 3 will be fought, but World War 4 will be fought with sticks and stones."A. Einstein

  22. World Energy Consumption and Fossil Fuel Supply vs Time

  23. Basic Nuclear Power Plant

  24. Fission Power Advantages • Supplies plentiful electricity • Conserves coal, oil, and natural gas • Reduces pollution from burning fossil fuel – sulfur oxides and carbon oxides

  25. Fission Power Disadvantages • Storage of radioactive wastes • Production of plutonium • Danger of nuclear weapon proliferation • Low-level release of radioactive materials into air and groundwater • Risk of accidental release of large amounts of radioactivity

  26. Controlling Nuclear Fusion • Fusion occurs at very high temperatures (on the order of 108 degrees) & densities • Problem? • All materials melt and vaporize at the temperature required for fusion • Solution – magnetic bottle or laser confinement • Still not cost or energy efficient • Difficult to sustain the reaction

  27. Fusion Benefits • No danger of runaway reactions • No air pollution – only helium is produced • By-products of fusion are not radioactive • Fuel is hydrogen (deuterium and tritium) • 30 kilograms of seawater contain 1 gram of deuterium • Fusion of 1 gram of deuterium releases as much energy as 10,000 liters (~2500 galllons) of gasoline or 80 toms of TNT

  28. Nuclear Links • http://www.ccnr.org/nuclear_primer.html • http://www.energy.ca.gov/education/story/story-html/chapter07.html • http://www.howstuffworks.com/nuclear-power1.htm • http://www-formal.stanford.edu/jmc/progress/nuclear-faq.html • http://sol.sci.uop.edu/~jfalward/nuclearreactions/nuclearreactions.html

  29. Chain Reaction – Critical Mass • http://www.npp.hu/mukodes/anim/sta1-e.htm • http://www.npp.hu/mukodes/anim/div2a-e.htm

  30. Critical Mass • critical mass a self sustaining reaction starts • for pure metal U235 (without moderator) the critical mass is somewhat less than 50 kg • Because of the very high density (19.2 g/cm3) this amount of uranium makes a sphere whose diameter is about 17 cm.

  31. Moderator • should have as low atomic mass number as possible • its neutron absorbing ability should be as low as possible • water (H2O), heavy-water (D2O), graphite (C) and beryllium (Be)

  32. Cherenkov Radiation • Bluish glow when charged particles travel faster than the speed of light in the medium

  33. Mass Spectrometer

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