Nuclear Energy Continued

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Nuclear Energy Continued
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• Radioisotope an unstable isotope that
  spontaneously changes its nuclear structure and
  releases energy in the form of radiation.

Isotopes
Stable
Radioisotopes
Unstable
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• An unstable atom with a nucleus that can
  spontaneously disintegrate is said to be
  radioactive.

Abundant
ßdecay
ß- decay
Stable Isotopes
Radioactive Isotopes
These are just a few examples, there are more
stable and unstable isotopes for tin!
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...
Abundant
All isotopes of Uranium are radioactive. None are
stable.
Isotopes
Stable
Radioisotopes
Unstable
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• How long does it take for a radioactive atom to
  disintegrate? How do we find out?
• Half-life the average length of time it takes
  radioactive material to decay to half of its
  original mass
• The half life of Cobalt-60 is 5.27 years. Does
  that mean that it takes 5.27 years for an isotope
  atom to decay?

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Example
50 g counting only the blue Cobalt-60 atoms

• half life of Cobalt-60 is 5.27 years

100 g
50 g
69 g
81 g
It takes 5.27 years for the sample to decay to
half of its original mass
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Example continued

• What if we wait another 5.27 years?

50 g
25 g
32 g
It takes 5.27 years for the sample to decay to
half of its original mass
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Trying it out

• Carbon-15 has a half-life of 2.5 s.
• If the sample is 100g, how much carbon-15 will be
  remaining after 10s?

Time (s) Mass of carbon-15 (g)
0 100
2.5 50
5 25
7.5 12.5
10 6.25
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Applications

• Which elements are used for determining the age
  of- a living thing that has died- the moon
  or the earth

Explanation together.
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Nuclear Fission
Same amount of energy in one reaction as about 7
million times as great as the energy released
when the same mass of dynamite explodes.
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Heavy water water that contains a high level of
deuterium
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Nuclear CANDU Reactor

• Our focus in this course the transformations of
  energy.

Photo source http//www.nucleartourist.com/type/c
andu.htm
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• Nuclear fission produces neutrons and thermal
  energy.
• Heavy water moderates neutrons and absorbs
  thermal energy.
• Thermal energy is transferred to the steam
  generator.
• Heavy water cools and flows back.
• Normal water absorbs thermal energy and vaporizes
  into steam.
• Steam pressure builds and transforms thermal
  energy into mechanical energy causing the turbine
  to turn.
• The electrical generator converts the mechanical
  energy into electrical energy.

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Nuclear Fusion

• Nuclear fusion a nuclear reaction in which the
  nuclei of two atoms fuse together to form a
  larger nucleus.

CNO chain
Proton-proton chain
Photo source http//en.wikipedia.org
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Nuclear Fusion

• Nuclear fusion produces significantly more energy
  per mass of fuel than fission reactions.
• The only man-made fusion device to achieve
  ignition to date is the hydrogen bomb.
• Nuclear fusion occurring in stars.