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Nuclear Fusion

Nuclear Fusion. The Possibility. Introduction. “Every time you look up at the sky, every one of those points of light is a reminder that fusion power is extractable from hydrogen and other light elements” -Carl Sagan, 1991. The Future of Fusion.

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Nuclear Fusion

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  1. Nuclear Fusion The Possibility

  2. Introduction • “Every time you look up at the sky, every one of those points of light is a reminder that fusion power is extractable from hydrogen and other light elements” -Carl Sagan, 1991

  3. The Future of Fusion • While renewables may be the “energy source of tomorrow,” fusion will likely be needed for “the day after tomorrow”

  4. Overview • Fusion will solve future energy shortfalls • Viable fusion power plants will solve pollution problems • Investment in fusion research and development will set the stage for future energy independence • U.S. involvement in International Thermonuclear Experimental Reactor (ITER) will aid development of fusion technology

  5. The Problems • Enormous monetary investment • Possibility of failure

  6. Conclusion The answer is fusion • Although the monetary investment involved is daunting the future benefits of establishing fusion as a viable power source for the U.S. and the world rise far above the obstacles that stand in the way

  7. Why Fusion? • Problems with current energy producing fuels • It is hypothesized that by 2050 we will have run out of economically recoverable fossil fuels

  8. Coal • Abundant • Burns dirty • Causes acid rain and air pollution • Greenhouse gas problems

  9. Oil • Flexible fuel source with many derivatives • Transportable • Finite supply • Causes air pollution

  10. Natural Gas • Burns cleanly • Transportable • Finite supply • Dangerous to handle

  11. Growing Population

  12. No More Fossil Fuel? Need For New Energy Sources • If we continue to burn fossil fuels for energy, they will only last another few hundred years. • This means that an energy shortfall could occur within the next fifty years.

  13. Nuclear Power • Clean • No CO2 • No immediate pollution • Problems with waste disposal • Safety concerns

  14. Other Alternative Sources • Water Power • Solar Power • Tidal Power • Wind Power • Geothermal Power 20% of the energy needed for an estimated world population of 10 Billion in 2050

  15. An Answer Nuclear Fusion

  16. Our Sun

  17. Abundant fuel, available to all nations Deuterium and lithium easily available for thousands of years Environmental Advantages No carbon emissions, short-lived radioactivity Modest land usage Compact relative to solar, wind and biomass Can’t blow up Resistant to terrorist attack Less than 5 minutes of fuel in the chamber Not subject to daily, seasonal or regional weather variation No large-scale energy storage nor long-distance transmission Can produce electricity and hydrogen Compliments other nearer-term energy sources Fusion Advantages

  18. Huge research and development costs Radioactivity Fusion Disadvantages

  19. Background Fusion Basics

  20. Basic Physics

  21. Energy-Releasing Reactions

  22. What is an atom?

  23. Nuclear fission Where heavy atoms, such as uranium, are split apart releasing energy that holds the atom together Nuclear fusion Where light atoms, such as hydrogen, are joined together to release energy Nuclear Power

  24. States of Matter • Plasma is sometimes referred to as the fourth state of matter

  25. Plasma makes up the sun and the stars

  26. In plasma the electrons are stripped away from the nucleus • Like charges repel • Examples of plasma on earth: • Fluorescent lights • Lightning • Aurorae • Neon signs Plasma Atoms

  27. Typical Plasmas • Interstellar • Solar Corona • Thermonuclear • Laser • Air Density

  28. Characteristics of Typical Plasmas

  29. Basic Characteristics • Particles are charged • Conducts electricity • Can be constrained magnetically

  30. Fusion Fuel • Tritium • Deuterium

  31. The fuel of fusion

  32. Inexhaustible Energy Supply • Deuterium • Constitutes a small percentage of the hydrogen in water • Separated by electrolysis • 1 barrel (42 gallons) water = ¾ oz. D = 32,000 gallons of oil • Tritium • n + Li T + He • Lithium is plentiful • Earth’s crust • Oceans • Savannah, Georgia • Canada, Europe, Japan

  33. Fusion Fuel: Deuterium

  34. Other Possible Fusion Fuels Helium-3 Nuclear Fusion Proton Proton Neutron Proton

  35. Where is Helium-3? • Helium-3 comes to us from the sun on the solar wind • It cannot penetrate the magnetic field around the earth, so it eventually lands on the moon • One shuttle load- 25 tons- would supply the U.S. with enough fuel for one year • China

  36. HOW FUSION REACTIONS WORK

  37. E=mc2 • Einstein’s equation that equates energy and mass • E= energy • M= mass • C= speed of light (3 x 108 m/sec) • Example: • energy from one raisin = 10,000 tons of TNT

  38. Two Main Types of Fusion Reactions: P-P "P-P": Solar Fusion Chain

  39. Two Main Types of Fusion Reactions: D-T D + T => He-4 + n

  40. More on Fusion Reactions

  41. An enormous payoff • The fraction of “lost” mass when H fuses into He is 38 parts out of 10,000 • This lost mass is converted into energy • The energy released from 1 gram of DT = the energy from about 2400 gallons of oil

  42. The result • Inexhaustible fuel source • Seawater & Lithium • The MOST “bang for your buck” • Inexpensive to produce • Widely distributed fuel source • No wars • No pollution • Helium is not polluting • Fuel that is non-radioactive • Residue Helium-4 is non-radioactive • Waste reduction

  43. More on Fusion Radioactivity • Aneutronic Fusion Fuels • More costly • Not enough science yet • Neutronic Fusion Fuels • D-T Reaction • Most of the neutrons are absorbed into a lithium blanket which is then used to replace the tritium fuel • Stray tritium atoms • The Reactor Structure

  44. More of Fusion Radioactivity • Stray Tritium • Relatively benign • Doesn’t emit strong radioactivity when it decays • So only dangerous when ingested or inhaled • Shows up in one’s body as water • Easily and frequently flushed out • Half-life of 12 years • No long-term waste problem • Won’t decay while in one’s body • Less than natural exposure to radon, cosmic rays and much less than man-made x-rays

  45. More on Fusion Radioactivity • Reactor Structure • Development of special “low-activation” structural materials • Vanadium • Silicon-carbide • Wait ten to fifteen years after shutdown • The reactor will be less radioactive than some natural materials (particularly uranium ores) • Recycle into a new fusion reactor

  46. Waste Reduction Power Source Total Waste (m3) High-Level RAD Waste Coal 10,000 (ashes) 0 Fission 440 120 Fusion: Today’s Materials 2000 30 Advanced Materials 2000 0

  47. So why aren’t fusion plants already in operation? How fusion works and the obstacles in the way

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