Document Classification: Machine Learning Techniques and Algorithms, Lecture notes of Physics of Energy Devices

Download Document Classification: Machine Learning Techniques and Algorithms and more Lecture notes Physics of Energy Devices in PDF only on Docsity! eSNyag’gerenver 2 10. Introduction and Motors (Oct. 3) Motors and Generators (Oct. 10) Distribution and use of Electricity (Oct. 17) The Wind (Oct. 24) Thermodynamics (Oct. 31) Heat Engines and Transportation (Nov. 7) Nuclear Fission (Nov. 14) Solar Power — Thermal and Electric (Nov. 21) Room 120; down the hall, down stairs or elevator. Special guest lecture (Dec. 5): "From the Freezer to the Frying Pan: Trying to Understand the Wackier Climates of Ancient Earth.” — Dorian Abbot Summary; the future (Dec. 12)  Talk next week Tuesday, November 17, 2009 Lester Brown, Plan B 4.0: Mobilizing to Save Civilization As fossil fuel prices rise, oil insecurity deepens, and concerns about climate change cast a shadow over the future of coal, a new energy economy is emerging. Wind, solar, and geothermal energy are replacing oil, coal, and natural gas, at a pace and on a scale we could not have imagined even a year ago. For the first time since the Industrial Revolution, we have begun investing in energy sources that can last forever. In Plan B 4.0, Lester Brown (founder and President of Earth Policy Institute) explores both the nature of this transition to a new energy economy and how it will affect our daily lives. This event is co-sponsored by the Program on the Global Environment. 6:00pm - 7:30pm in Assembly Hall. (International House)  Orientation Pressurized Water Reactor (PWR)  Primary energy sources O Table 1: Electrical power sources, nationwide vs. my ComEd bill. Source: Electric Power Monthly, September 2009, EIA. Petroleum includes both liquids and coke. Renewables here in- cludes biomass and geothermal. ComEd bill July 2009. Fuel Nationwide Ed Coal 45.0 Nuclear 20.8 NaturalGas 21.4 Petroleum 1 Hydro 7.6 Renewables 3.8  A timeline of rapid development * 1932 — discovery of the neutron ¢ 1938 — fission * 1942 — sustained reaction, Chicago, complete secrecy. * 1945 — nuclear weapons, shortly, fusion * 1951 — electricity (EBR-1, Idaho) * 1954 — Obninsk Plant, ~5 MW * 1956 — Commercial plant, Calder Hall, 50 MW * 1957 — Commercial US plant, Shippingport, PA ¢ Worldwide ~14% nuclear ¢ US Today: 108 power plants and 20-22% electricity * France: 77% nuclear Fic. 5. A layer of the pile.  Fission — masses and energies oe-—_—_> n U235 U236* collision and capture | deformation  .-_—_> n U235 U236* collision and ; capture deformation Reactants: 1.0087 u + 235.0439 u = 236.0525 u (atomic mass units u) Products: 146.9282 u + 86.9207 u + 2 x 1.0087 U = 235.8663 u. The mass of the products is 0.19 u less than the reactants. Why? E=mc?! 1atomic mass unit = 1.66x10~27 kg but can use m = E/c? to define mass units Anew unit of mass in terms of the energy, MeV/c? the energy is measured in MeV, or million-electron volts. This is the energy that an electron has after it has moved across a potential difference of a million volts. In these fun units: c2 = 931.494 MeV/u implies that this fission releases 177 MeV.  Aside: Don’t believe in anti-matter or E=mc?? O ¢ E=mc? implies that the electron is 0.511 MeV/c? * 22Na decays through positron emission ¢ These positrons can annihilate with electrons to produce two 0.511 MeV gamma rays. e Thus, the mass of the electron and positron is converted into energy of two (massless) photons.  The 238U Cross section cross section (barns) O Neutron cross sections of U238 " U-238 total fission ------~ 10000 1e+06  The 238U and 235U Cross section cross section (barns) O Neutron cross sections of U238 U-238 total fission ------~ U-235 total fission Just when things made sense... 235U has no threshold 1 100  Activation and binding 3 1 2 o> —e\e@ @ U235 U236* collision and capture deformation Activation energy ~ 6 MeV °35U case: mass(23°U*) = mass(235U) + mass(neutron) = 236.0526 u mass(ordinary 73°U) = 236.0456 u -> mass difference in energy units is 6.5 MeV mass(?3°U") is therefore excited with 6.5 MeV energy and activation is only 6.2 MeV Thus if 235U absorbs a neutron at rest, it will induce fission! 238U case: 4.8 MeV from forming 739U*, but 6.5 MeV to induce fission.