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Radioactivity is the process by which atomic nuclei emit radiation in the form of particles and rays. This guide covers the four types of radiation: alpha particles, beta particles, and gamma rays, including their compositions and penetration powers. Additionally, it explores radioactive decay, including half-lives and transmutation reactions, and details fission and fusion processes. We also discuss nuclear reactors and the challenges associated with spent fuel rods, crucial elements in harnessing nuclear energy safely.
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Radioactivity • The process by which nuclei emit particles and rays • These penetrating particles and rays are called radiation.
4 • Symbol is 2He or 2α 4 Types of Radiation • Alpha particle-two p+ and two n0 (helium nucleus) • Changes identity of the atom (drops by two atomic #’s) • Little penetrating power (stopped by paper or skin)
Types of Radiation • Beta particle- a high speed e- • Comes from a neutron that breaks apart • Changes identity of the atom (up one atomic #) • Stopped by Al foil or wood • Symbol is -1e or -1β
Types of Radiation • Gamma Radiation • High-energy photon emitted as a gamma ray • Often emitted along with α or β radiation • Does not change identity of the isotope • Highly penetrating and very dangerous to humans
Radioactive Decay as Equations • The symbols for the various particles are shown: • When a radioisotope changes identity, this is called a transmutation reaction.
Half-Life • Every radioisotope has its own rate of decay measured by its half-life. • Half-life (t½) is the time required for half the nuclei of that radioisotope to decay • Could be a fraction of a second or billions of years.
Fission • When nuclei of some isotopes are hit with neutrons, they split into smaller fragments. This is fission. • Every time an isotope splits, TREMENDOUS amounts of energy are released.
Fission Chain Reaction • In a chain reaction, the neutrons produced strike other atoms, which produce more neutrons, etc. • This is how a nuclear bomb works. • It is also how reactors work, but with controls.
Nuclear Reactors • Make use of the energy produced by fission.
Nuclear Reactors • The fuel rods from reactors, when spent, are a major waste issue. • They are stored indefinitely, or shipped to another location. • They won’t be safe until the isotopes are stable, which depends on the half-life of the isotope. • The next slide has some fuel rod photos.
Fusion • Occurs when nuclei combine to produce a heavier nucleus. • Occurs naturally in the sun. (4 H nuclei become 1 He nucleus) • It is how current nuclear warheads work.
