Nuclear Energy

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Nuclear Energy

• Radioactivity and Half-Life
• Fission
• Fusion

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Radioactivity

• The process in which an unstable atomic nucleus
  emits charged particles and energy.

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NUCLEAR REACTIONS PRODUCE RADIATION

• Protons and neutrons determine nuclear reactions
• One must understand atomic structure to
  understand radiation

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RADIOACTIVE DECAY

• Radioactive decay refers to the spontaneous
  emission of radiation from the nucleus of an
  unstable atomic nucleus
• The ratio of neutrons to protons is largely
  determinant of the stability of the nucleus and
  the tendency for radioactive decay
  to occur

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Types of Nuclear Radiation

• Alpha decay
• Beta decay
• Gamma decay

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Alpha decay

• Emits alpha particles which are positively
  charged particle
• Are the least penetrating type of nuclear
  radiation
• Can be stopped by a sheet of paper

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Beta decay

• Release of negatively charged particle
• Are more penetrating than alpha particles.
• Can be stopped by a thin piece of metal

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Gamma decay

• Nuclear radiation consisting of a stream of
  particles with no charge and very little mass
• A form of high energy electromagnetic radiation
  (high frequency low wavelength)
• Most penetration power

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Half-life

• Is the time required for half of the radioactive
  substance to decay (as either alpha, beta, and
  gamma radiation)
• Nuclear decay rates are constant for specific
  elements
• Practical uses Radioactive dating
• Examples
• The half-life of isotope X is 2.0 years. How
  many years would it take for a 4.0 mg sample of X
  to decay and have only 0.50 mg of it remain?

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Nuclear Fission

• Practical Applications

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Fission

• Is the splitting of an atomic nucleus into 2
  smaller parts
• Tremendous amounts of energy in the form of gamma
  rays can be produced from very small amounts of
  mass
• Chain reaction-neutrons released during the
  splitting of an initial nucleus triggers a series
  of nuclear fissions.

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Examples

• Power Plants run off of the fission of
  Uranium-235
• Nuclear weapons are an example of an uncontrolled
  chain reaction

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Fission of Uranium
Barium and Krypton represent just one of many
potential outcomes
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Nuclear Disaster-Chernobyl
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Fusion

• Is a process in which the nuclei of two atoms
  combine to form a larger nucleus
• Can release huge amounts of energy in the form of
  high energy gamma rays

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Fusion cont.

• Temperatures are so high that matter exists as
  plasma. The sun is 10,000,000 degrees Celsius
• Plasma-a state of matter where atoms have been
  striped of their electrons.
• 2 problems are creating high temperatures and
  containing the plasma

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