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Published byImogene Fisher Modified over 9 years ago
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How does nuclear reactor work. 7:30 min http://www.youtube.com/watch?v=LTnfXLws40Q Fukushima 3 min http://www.youtube.com/watch?v=BdbitRlbLDc http://www.youtube.com/watch?v=f2aXsZDWRUA Fukushima Now 14 min
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Energy from Fission & Fusion
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Binding E per Nucleon.
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Fission – liberates E. Can use particles (n o ) to induce fission. Typical 235 U + 1 n 236 U 90 Sr + 144 Xe +2 1 n +E. 92 0 92 38 54 0. The ejected neutrons can split more U-235.
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Fission can be self sustaining. It will continue until all the U-235 used up. For bombs, we don’t bother to control the n o produced. We want a runaway chain rx. In power plants, we do control the reaction to block the neutrons using control rods.
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Control Rods control rx rate by blocking or absorbing some of n o formed in rx.
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Nuclear Power Plant – induces fission in Uranium. U – 235 bombarded with neutrons. Fission is started. U splits into parts and emits more neutrons. These released n o start chain reaction.
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Nuclear Power Makes use of artificial transmutation to get fission process going. Uranium is bombarded with neutrons. Moderators are used to slow the neutrons. Nuclei need slower n o or they cannot absorb. Critical Mass is the minimum amount of U-235 to get fission process going.
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Nuclear Fusion 2 light nuclei combine forming heavier ones. H combines to form He. Process that fuels the sun and other stars.
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Fusion Deuterium & Tritium
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Typical Hydrogen Fusion Rx 3 parts. H-1 + H-1 fuses to H-2 +E. H-1 + H-2 fuse to He-3 + E He-3 + He-3 fuse to He-4 + H-1 + E. Liberates tons of energy.
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Problems: Need high KE to smash nuclei Need to contain very high temperatures and pressures. Energy released would cause matter to ionize and go into plasma state.
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Bainbridge Mass Spectrometer Used to find mass of different nuclei. Verifies that isotopes exist. Uses electric and magnetic fields to accelerate and deflect nuclei.
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Mass spec begins with source (usu. Heating) to strip nuclei of e- which get accelerated through p.d. The velocity is controlled by crossed electric and magnetic fields which balanced forces. Ion source X X X - - - - - - - ++++++ Velocity F elc = F mag. Control Eq = qvB v = E B p.d. e- will fly straight F net =0
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The beam enters a vacuum with a magnetic field & is deflected into a curved path. X X X - - - - - - - ++++++...... F c = F mag. mv 2 = qvB r mv= qBr Radius of curvature is proportional to mass. Large masses don’t curve as much. detectors.
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