Nuclear Fission Nuclear Fission n Chain reaction that

Nuclear Fission

Nuclear Fission n Chain reaction that splits atoms and releases E as a result n Reaction begins with a neutron § Used in weapons & nuclear power plants § 238 U + 1 n 239 U 92 Kr + 141 Ba + 31 n

Yeah! Nuclear Power! n Produces 3, 000 times the energy as coal by mass n Fission of 1 mole U-235 releases 2. 0 x 1010 k. J when 0. 22 g is lost n Coal and fossil fuels are nonrenewable energy sources

Yikes! Toxic Waste n U-235 is present in rock but only 0. 3% and expensive to mine n Reaction can be “controlled” but not stopped once it is started n Lots of toxic waste, for a long time (240, 000 years) n Reactor safety is an issue!

Anatomy of a Nuclear Power Plant

Power Plants in the world:

Fission Weapons: On August 6, 1945, a uranium-based weapon, "Little Boy", was let loose on the Japanese city of Hiroshima.

Fat Man: Implosion-Type Bomb The actual bomb, “Fat Man” dropped 3 days after “Little Boy” July 16, 1945, 1 st test “Trinity”

Nuclear Fusion

Fusion n Two hydrogen nuclei “fuse” together to form a helium nuclei and release lots & lots of E n Fuel of the stars! n 2 H + 2 H 4 He

What’s good about fusion: n Fuel is inexpensive & abundant n 0. 0000001 % of hydrogen in ocean would fuel the entire world for one year! n No toxic waste n Reaction can be stopped anytime n Never-ending energy! n Fission = 1 kg Uranium = 3, 000 kg coal BUT 1 kg Hydrogen fusion = 40, 000 kg of coal

Too good to be true? 2, 000 °Celsius to start reaction n Needs to be very hot! n Thermonuclear weapons, or Hydrogen bombs use several explosives: dynamite → fission to get heat → fusion! n Power plants in research phase…TOKAMAK reactor n http: //www. youtube. com/watch? v=Pv. ISgdw. MGRs.