Nuclear energy

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Nuclear energy

  1. 1. 1 Atomic Mass Unit 2 Nuclear Fission 3 Nuclear Fusion 4 Energy in Nuclear Reaction 5 6 Electricity Generation from Chain Reaction Nuclear Power Plant Utilisation
  2. 2.  a.m.u is usually used to quantify the mass of subatomic particles like protons, neutrons and electrons.  1 a.m.u is equal to 1/12 of the mass of carbon-12 atom.  a.m.u can also be written as u.   1u = 1/12 x mass of one carbon-12 atom = 1/12 x 1.99265 x 10-26 kg = 1.66 x 10-27 kg Useful in computation of energy released in nuclear reaction.
  3. 3. Splitting of a heavy nucleus into two lighter nuclei neutron fission product neutron neutron target nucleus fission product neutron
  4. 4. Release enormous amount of energy A few hundred million times the energy released in an equivalent chemical reaction.  kinetic fragments 
  5. 5. n n n n n n n
  6. 6. Combining of two lighter nuclei to form a heavier nucleus Initially, under an applied force, 2 lighter nuclei fuse together to form a heavier nucleus and energy.  At a critical level, the energy released can self sustain the fusion reaction. Deuterium Helium  Energy Tritium Neutron
  7. 7. Energy released in nuclear fusion is very much more than in nuclear fission Appear as kinetic energy of heavier nucleus and energy of neutron, proton or gamma rays 
  8. 8. 4g 10 g ENERGY 5.9999 g
  9. 9.  Mass and energy are not conserved separately.  The total “mass-energy” before and after the exchange is conserved.  They can be exchanged from one form to the other.
  10. 10. loss of mass or mass defect (kg) energy released (J) E= 2 mc speed of light = 3.00 x 108 ms-1
  11. 11. Example 226 Ra 88 226 Ra = 226.025406 u, 88 222 4 Rn + He 86 2 222 Rn = 222.017574 u, 86 4 He = 4.002603 u, 1 u =1.66 x 10-27 kg 2 c = 3.00 x 108 ms-1 Mass defect, m = 226.025406 u – (222.017574 u + 4.002603 u) = 0.005229 u = 0.005229 x 1.66 x 10-27 kg = 8.68 x 10-30 kg Therefore, energy released, E = mc2 = 8.68 x 10-30 x (3.00 x 108)2 = 7.81 x 10-13 J
  12. 12. Trigger chain reaction Release enormous energy Energy conversion in reactor Electricity generation
  13. 13. Generation III reactors Water reactors Boiling water reactors  Gas-cooled reactors  Pressurised water reactors  Pressurised heavywater reactors  Light water reactors  Heavy water reactors  High temperature gas-cooled reactors  Fast neutron reactors 
  14. 14. Boiling water reactor
  15. 15. Pressurised water reactor
  16. 16. Pressurised Heavy-Water Reactor
  17. 17. Light-water graphite-moderated reactor
  18. 18. Liquid-Metal-Cooled Fast-Breeder Reactor (LMFBR)
  19. 19. Heavy Water Reactor
  20. 20. High Temperature Gas-Cooled Reactors
  21. 21. Fast neutron reactor
  22. 22. absorb neutrons. Reduce rate of fission reaction GCR: Function moderator slow down neutrons produced by fission nuclei split by neutrons, releasing large amount of energy Prevent radiation leakage from reactor core rotated by flow of steam under high pressure coils rotated by turbines. Electricity generated by electromagnetic induction Boil water into steam
  23. 23. Layout of GCR
  24. 24. GCR: Process flow Gas passing through the reactor core is heated up Fission of uranium-235 nuclei produces energy in the form of heat Cold gas goes back to the reactor core to be heated again Heat energy from the hot gas boils the water into steam Flow of steam drives the turbines Steam condenses back to water Turbines turn the coils in the generator to produce electricity
  25. 25. Energy conversions in GCR Heat energy carried by the hot gas Nuclear energy from fission Kinetic energy of the steam Kinetic energy of the turbines Electrical energy
  26. 26.  More than 400 nuclear power stations, producing 17% of the world’s electricity  East & South Asia, more than 100 nuclear power reactors in operation 29% 38%
  27. 27. Advantages  Minimal carbon dioxide emission  More stable price compared to fossil fuel  Need less fuel Disadvantages  Exposure to excessive radiation  Expensive  Misused as weapons of mass destruction

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