22 Apr 16 Fusion, Review, Assorted For Slideshare


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Fusion, Fusion Energy, Fusion Weapons

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22 Apr 16 Fusion, Review, Assorted For Slideshare

  1. 1. Today: Fusion & Review Exam #3 is a week from today! 1/3 millimeter Electron Microscope Image of MEMS Force Sensor
  2. 2. Quiz 8
  3. 3. Quiz 8 Chemical reactions involve interactions of electrons The nuclei do not change, elements remain the same!
  4. 4. Quiz 9 Discuss!
  5. 5. Quiz 9 These have atomic mass number zero
  6. 6. Quiz 9
  7. 7. A question probably on the next quiz (Which has more mass?)
  8. 8. Protons and neutrons weigh LESS when bound together! More decrease in mass + 0 + + + 0 + + 0 0 0 0 Carbon-12 nucleus, Mass = 12 u (by definition) + 0 Single free proton Mass = 1.007825 u Single free neutron Mass = 1.008665 u You need to ADD energy to take apart a C-12 nucleus
  9. 9. Uranium-235 decreases in mass during fission <ul><li>One possible fission reaction is: </li></ul><ul><li>U-235 + neutron  Ba-141 + Kr-92 + 3 neutrons </li></ul>Ending mass = 99.9% of starting mass 0.1% Missing mass = kinetic energy of products (and some gamma rays) <ul><li>Fission of 1000 kilograms of Uranium-235 releases 1 kilogram of mass energy </li></ul><ul><ul><li>Equivalent to a few days of U.S. electrical needs </li></ul></ul>(true: free neutrons do increase in mass)
  10. 10. Clicker question—Mass energy available <ul><li>Which reaction can potentially release more energy per nucleon </li></ul><ul><li>More energy can be released per fission event </li></ul><ul><li>More energy can be released per fusion event </li></ul>
  11. 11. Immediately, Nuclear Fusion was recognized as an even greater source of energy And of course, hydrogen is a very abundant element!
  12. 12. Fusion power first harnessed for weapons <ul><li>Hyrdrogen fusion initiated by “conventional” fission bombs </li></ul><ul><li>Fusion bombs or “H-bombs” 100’s of times more powerful than fission bombs </li></ul>User:Boostin on wikipedia
  13. 13. Fission energy took 18 months to harness We are still waiting for fusion power!!! <ul><li>Conceptually, fusion is as simple as fission </li></ul><ul><ul><li>E.g. the sun shown above </li></ul></ul><ul><li>In practice, fusion is way way way way way way way way harder to control in a machine (fusion weapons work well, but not good for a reactor) </li></ul>ITER Magnetic confinement fusion experiment The sun is a successful fusion reactor http://www.youtube.com/watch?v=SQ9j2cajRo4&feature=related
  14. 14. Remember to study quizzes for exam! One topic that we will cover is diffraction and interference of light. Let’s review a little by looking at applications. We stopped lecture here, because I became confused about exam #3 topics! Exam #3 DEFINITELY contains interference!