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Nuclear Power

Nuclear Power. The Basics…. Nuclear Trivia. Utilities develop in 1950’s Atomic Energy Commission – promised utilities cheap electricity Gov’t pay ¼ building cost Price Anderson Act Liability protection By ’96 : gov’t subsidized $2T.

melyssa-simpson
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Nuclear Power

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  1. Nuclear Power The Basics…

  2. Nuclear Trivia • Utilities develop in 1950’s • Atomic Energy Commission – promised utilities cheap electricity • Gov’t pay ¼ building cost • Price Anderson Act • Liability protection • By ’96 : gov’t subsidized $2T

  3. 437 commercial reactors in 32 countries, producing 17% electricity

  4. www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

  5. Uranium 92U238.02891 How many protons? How many electrons? How many neutrons? 6 C Carbon 12.011 92 protons 92 electrons 146 neutrons

  6. Radioactivity • Radioactivity: Nuclear changes in which unstable (radioactive) isotopes emit particles & energy • Radioactive decay continues until • original isotope (radioisotope) stable isotope www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

  7. NUCLEAR CHANGE • Isotopes  vary by number of neutrons • Spontaneously undergo change (vary neutrons) • 3 types: radioactive decay nuclear fission nuclear fusion

  8. Radioactive Decay • Emits high energy radiation &/or particles • Gamma radiation • Alpha particles • Beta particles • The isotopes “shoot out” these particles, forming different isotopes • The rate this change occurs at = half-life

  9. Nuclear Energy = The energy that exists within the nucleus of an atom. Nuclear Fission = the release of energy from the splitting of atoms. Nuclear Fusion = the combining of two smaller atoms into one larger atom. http://videos.howstuffworks.com/hsw/11945-nuclear-energy-introduction-to-nuclear-energy-video.htm

  10. Nuclear Fission Nuclear Fusion Sun and stars and CERN 2 small (light) isotopes are forced together H + H = He Need temps > 100,000,000ºC Releases more E than fission • Bombs & power plants • Big, unstable isotopes are struck by neutrons, which splits the isotope’s nuclei • More neutrons “shoot out” to strike nearby isotopes, causing a chain reaction.

  11. When people think about nuclear power they think about… • Effects of radiation • Nuclear disasters • Nuclear waste disposal

  12. What is Radiation? • Radiation = particles given off by unstable atoms. • 3 Types: • Alpha (α) • Travels few inches • Blocked by paper (skin) • Beta (β) • Travels few feet • Blocked by aluminum, glass • Gamma (γ) • Travels far • Blocked by lead (steel & concrete).

  13. www.geology.fau.edu/course_info/fall02/ EVR3019/Nuclear_Waste.ppt

  14. Background Radiation • The amount of radiation we are exposed to daily from the environment • Average = 360 millirem/year

  15. Effects of Radiation • Genetic damages: from mutations that alter genes • defects can become apparent in the next generation • Somatic damages: to tissue, such as burns, miscarriages & cancers www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

  16. Nuclear Power Plant A controlled nuclear fission chain reaction  heats water produce high-pressure steam turns turbines  turns generator and creates electricity. http://www.howstuffworks.com/nuclear-power2.htm

  17. Controlled Nuclear Fission Reaction cstl-cst.semo.edu/bornstein/BS105/ Energy%20Use%20-%203.ppt

  18. Nuclear Reactor: Summary Core 35-40,000 fuel rods Uranium oxide pellets 97% U238 (nonfissionable), 3% U235 Control rods Absorb neutrons Moderator Slows down neutrons, maintains chain rxn. Water [75%], solid graphite [20%], heavy water (D2O) [5%] Coolant Transfers heat to steam lines Prevents meltdown

  19. http://www.animatedsoftware.com/environm/nukequiz/nukequiz_one/nuke_parts/reactor_parts.swfhttp://www.animatedsoftware.com/environm/nukequiz/nukequiz_one/nuke_parts/reactor_parts.swf www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

  20. Domed building Where nuclear fission occurs. Surrounded by thick concrete, steel & lead. Blocks all radiation! Nuclear Reactor

  21. Fuel Rods 35,000 – 70,000 fuel rods 3% Uranium-235 pellets In water (moderator) Control Rods absorb extra neutrons Control the chain reaction Inside the Reactor

  22. Cooling Tower • Water is the coolant in the system. • Tower is used to condense hot steam to liquid water. • Usually taken from river, lake, ocean. • Water can be reused.

  23. What are the parts? How does this design protect us?

  24. Nuclear waste • Power plants produce radioactive wastes • mostly spent fuel rods (~5 years) • each reactor produces about 20-30 tons yearly • Currently stored in pools on site • some remain “hot” for tens of thousands of years • How should we store this waste?

  25. Half-Life = time needed for one-half of the nuclei in a radioisotope to decay and emit their radiation to form a stable isotope Half-time emitted Uranium 235 710 million yrs alpha, gamma Plutonium 239 24.000 yrs alpha, gamma www.bio.miami.edu/beck/esc101/Chapter14&15.ppt

  26. Decommissioning Life span of a power plant = 15-40 years Parts wear out, Fuel is spent Plant is shut down Highly radioactive for 240,000 years Must store for 10 times the half-life What can we do with them?

  27. Low-Level & High Level Radioactive Waste Emit small amounts of ionizing radiation Stored 100-500 years 19401970: put in steel drums, dumped in ocean (still UK & Pakistan) 1970+: gov’t run landfills • Stored for thousands of years • Mostly spent fuel rods (240,000 yrs) • Safety debate • Options: • Keep onsight • Bury • Shoot into space • Bury in ocean floor • Bury in Antarctica • Change it into harmless

  28. Renewable or Non-Renewable?

  29. What do you think? What are the pros and cons for nuclear energy? What should we do with radioactive waste?

  30. http://streaming.discoveryeducation.com/search/assetDetail.cfm?guidAssetID=BE0FB49C-7C70-4C56-95F2-B3904BC9077Fhttp://streaming.discoveryeducation.com/search/assetDetail.cfm?guidAssetID=BE0FB49C-7C70-4C56-95F2-B3904BC9077F • 10 min video on nuclear energy • Fission, fusion, overview

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