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Nuclear Fission. Requirement # 3 . Make a drawing showing how nuclear fission happens. Label all details. Draw a second picture showing how a chain reaction could be started. Also show how it could be stopped. Explain what is meant by “critical mass”. The Fission Process.
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Requirement # 3 • Make a drawing showing how nuclear fission happens. Label all details. Draw a second picture showing how a chain reaction could be started. Also show how it could be stopped. Explain what is meant by “critical mass”.
How does fission work? • A neutron hits a uranium nucleus. • The nucleus becomes unstable and needs to release energy. • The nucleus breaks releasing energy, neutrons and 2 smaller atoms. • The 2 smaller atoms formed are called fission fragments.
Example of Chain Reactions • Dominos • Bowling • Billiard Balls
Your turn to draw a fission diagram • Get into groups of 2 and draw a picture of fission on the large paper provided. • On your diagram be sure to include: -original neutron -nucleus -fission fragments -new neutrons formed -energy released by the nucleus
Example of a fission diagram = Nucleus = fission fragment = Neutron = Energy
Critical Mass • The amount of nuclear fuel necessary to sustain a chain reaction. • You must have a critical mass in order to build a nuclear reactor. • You must have a critical mass in order to make a nuclear weapon.
How do we control the chain reaction? • Control Rods are made of a material that absorb the neutrons. • As the control rods are removed the chain reaction increases, and if we want to slow the reaction control rods are inserted. • At the Penn State reactor the control rods are made of boron.