Nuclear fission

Binding energy per nucleonA nuclear reaction derives its energy from the binding energy of the nucleus. If a large nucleus such as uranium is broken apart, energy can be released. Splitting a nucleus is called a nuclear fission reaction. An example is the nuclear reaction that splits the U 92 235 nucleus into two products, strontium-94, and xenon-140. The energy released by this reaction can be estimated with an energy balance calculation of the binding energy. Read the text aloud
From the binding energy plot we see that the binding energy per nucleon for uranium, xenon, and strontium are approximately 7.6, 8.4, and 8.8 MeV, respectively. The energy released is then approximately equal to E released = ( 8.4 MeV )× A Xe +( 8.8 MeV )× A Sr ( 7.6 MeV )× A U = ( 8.4 MeV )×140+( 8.8 MeV )×94( 7.6 MeV )×235=217 MeV This is very close to the actual energy release, which is 208 MeV. Read the text aloud
Process of a nuclear fission reaction for uranium-235
What initiates a fission reaction? In the late 1930s, German physicist Lise Meitner and chemists Otto Hahn and Fritz Strassmann discovered that bombarding uranium atoms with neutrons can initiate a fission reaction. The incoming neutron is initially absorbed into the U 92 235 nucleus, turning it into an unstable U 92 236 nucleus. The U 92 236 nucleus then undergoes decay into a pair of nuclei, ejecting two neutrons.
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Nuclear chain reactionBombarding a U 92 235 atom with one neutron can cause a nuclear fission reaction that ejects two neutrons. If there are many uranium atoms nearby, then those two ejected neutrons can initiate two new fission reactions that eject a total of four neutrons. Those four neutrons can start four new fission reactions that produce eight neutrons, and so on. This process is called a chain reaction and it is the key to continuous nuclear energy production. Read the text aloud
Which of the following atoms might act as fuel for a nuclear fission reactor?
  1. hydrogen
  2. helium
  3. carbon
  4. plutonium
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