Addendum to Nuclear Power

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Addendum to Nuclear Power
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Uranium-235

• Uraninium
• Uranium is a fairly common element on Earth,
  incorporated into the planet during the planet's
  formation. Uranium-238 (U-238) has an extremely
  long half-life (4.5 billion years), and therefore
  is still present in fairly large quantities.
  U-238 makes up 99 percent of the uranium on the
  planet. U-235 makes up about 0.7 percent of the
  remaining uranium found naturally.
• Uraninium-235
• Because Uranium-235 is able to undergo induced
  fission, it useful for both nuclear power
  production and for nuclear bomb production.
• If a free neutron runs into a U-235 nucleus, the
  nucleus will absorb the neutron without
  hesitation, become unstable and split
  immediately.

Induced fission
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Nuclear Power

• Nuclear power plants provide about 17 percent of
  the world's electricity.
• In France, about 75 percent of the electricity is
  generated from nuclear power.
• In the United States, nuclear power supplies
  about 15 percent of the electricity overall, but
  some states get more power from nuclear plants
  than others.

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Enrichment

• A sample of uranium must be enriched so that it
  contains 2 percent to 3 percent or more of
  uranium-235.
• Three-percent enrichment is sufficient for use in
  a civilian nuclear reactor used for power
  generation.
• Weapons-grade uranium is composed of 90-percent
  or more U-235.

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Nuclear Power Plant

• Typically, the uranium is formed into pellets
  with approximately the same diameter as a dime
  and a length of an inch.
• The pellets are arranged into long rods, and the
  rods are collected together into bundles and
  submerged in water inside a pressure vessel.
• In order for the reactor to work, the bundle, has
  to have the tendency to overheat and melt.
• The water acts as a coolant.
• To prevent the overheating, control rods made of
  a material that absorbs neutrons are inserted
  into the bundle using a mechanism that can raise
  or lower the control rods.
• Raising and lowering the control rods allow
  operators to control the rate of the nuclear
  reaction.

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Reactor Control Rods
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Nuclear Power Plant, cont

• The uranium bundle in the reactor acts as an
  extremely high-energy source of heat.
• It heats the water, creating steam, which drives
  a steam turbine, spinning a generator to produce
  power.

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Can you answer all of these?

• Where do you find the coolant?
• Where do you find the moderator? What does it
  do? What is it usually made of?
• What is released from the cooling tower?
• What is the containment structure made of?
• What is a half-life? Why is it important?
• Besides, U-235,which other element is used in
  nuclear reactors?