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Nuclear Reactions. Powering the Sun since 4.6 Billion B.C. Nucleus. Nuclear Reactions. Occur when the nucleus of an atom is changed Nuclear Reactions release the most energy of any type of reactions. http://education.jlab.org/qa/atom_model_03.gif. Fission.
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Nuclear Reactions Powering the Sun since 4.6 Billion B.C.
Nucleus Nuclear Reactions • Occur when the nucleus of an atom is changed • Nuclear Reactions release the most energy of any type of reactions. http://education.jlab.org/qa/atom_model_03.gif
Fission • When a large nucleus is split into two or more smaller nuclei • Only certain elements’ nuclei will fission, or split • Uranium & plutonium are the most common fissionable elements http://holvoet.free.fr/Voyage/energy/img/fission_v.gif
Fission • Nuclear Chain Reaction • When one fission reaction sets off several other fission reactions, which each set off new fission reactions. http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_17/FG17_10.JPG
Nucleus: U or Pu Neutron What happens during a fission reaction? 1. A large nucleus is hit with a neutron. http://www.oup.co.uk/images/oxed/children/yoes/atoms/fission.jpg
Nucleus: U or Pu Energy! Neutron What happens during a fission reaction? 2. The neutron makes the nucleus of the atom split. http://www.oup.co.uk/images/oxed/children/yoes/atoms/fission.jpg
Nucleus: U or Pu Energy! Neutron What happens during a fission reaction? 3. Large amounts of energy are released when it splits http://www.oup.co.uk/images/oxed/children/yoes/atoms/fission.jpg
Nucleus: U or Pu Neutrons Energy! Neutron Gamma Ray What happens during a fission reaction? • 4. A few neutrons are sent flying from the split nucleus. • These neutrons start new fission reactions http://www.oup.co.uk/images/oxed/children/yoes/atoms/fission.jpg
Fission • Critical mass • The smallest amount of uranium or plutonium that is needed to start a chain reaction. • The critical mass for Uranium is around 33 pounds.
Fusion • When two small nuclei join together to form a larger nucleus • Fusion releases much more energy than fission
Energy! What Happens in a Fusion Reaction? Hydrogen-2 (Dueterium) neutron Hydrogen-3 (Tritium) Helium http://www.generalfusion.com/images/reaction2.gif • Two hydrogen nuclei smash together at very high speeds • The hydrogen nuclei stick together (or fuse) to make a larger nucleus • Huge amounts of energy are released
Where does fusion happen? • Occurs in the Sun and other stars • Fusion bombs (H-bombs)