Chapter 11: Nuclear Energy: Benefits & Risks

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Chapter 11 Nuclear Energy Benefits Risks

• Fact 7 of energy consumed worldwide comes from
  nuclear power

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The Nature of Nuclear Energy

• Two types Fusion and Fission
• Fusion
• Two or more lighter nuclei combine to form
  heavier nucleus energy, e.g., hydrogen fusion
  to helium
• Takes place inside core of Sun
• Takes place in an H-bomb
• Not feasible as a controlled energy source, too
  hot to contain

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The Nature of Nuclear Energy

• Fission
• heavy nucleus splits into smaller particles
  energy
• Example First atomic bombs, like those dropped
  on Hiroshima Nagasaki
• Can be controlled and used as a source of
  commercial energy Nuclear power plants

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Figure 11.2
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Nuclear Reactors Power Generation

• Several types, most use Uranium-235 (some
  Pu-239) as fuel
• Energy is released, which is used to heat water
  to make steam, which is used to turn a turbine to
  generate electricity
• Figure 11.4 gt

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Nuclear Fuel Cycle fig 11.9

• U-235 is a nonrenewable resource (just like
  fossil fuels), it is mined (expensive)
• Typical uranium ore contains only 0.2 Uranium
• Of that 99.3 is U-238 (not usable) and 0.7
  U-235
• So, ore must be enriched (expensive) and made
  into fuel rods
• Fuel rods used in reactors last about 3 years,
  but still have radioactivity left spent fuel
  rods gt radioactive waste
• Disposal of this waste is a major problem

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Nuclear Waste Disposal

• Fuel rods placed in sealed casks, then
• High-level (of radiation) waste disposal
• Or, burial in geologically stable area
• NIMBY problems

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Yucca Mountain, NV -- fig. 11.18

• http//www.epa.gov/radiation/yucca/

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Nuclear Power Concerns

• No fear of nuclear explosion (like a nuclear
  bomb)
• Greatest fear if proper safety measures arent
  followed (human error!), reactor can overheat and
  cause a steam explosion, which throws radioactive
  material a long distance
• Ex Chernobyl disaster of 1986, pp. 234-235
• Ex (almost happened) Three-Mile Island, PA 79

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Nuclear Power Concerns...

• Exposure to radiation (see table 11.3, p. 237)
• Note Not from nuclear power plants!
• Concern is from handling ore, fuel rods, waste
• Thermal pollution
• water used to cool reactor gets returned to
  natural water system (lake, river, ocean)
• some species are sensitive to temperature
• fossil fuel plants also release hot water, but
  not as much as nucs (1/2 waste heat instead of
  2/3)

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Nuclear Power Concerns...

• Decommissioning costs
• All power plants have a finite life 30-40 years
• Must then be decommissioned, or taken apart in
  a systematic and careful way quite expensive to
  do right (50 million - 3 billion)
• Waste disposal
• already discussed

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Nuclear Power Benefits (?)

• Produces no air pollution!
• No CO2 (global warming), CO, no nitrogen or
  sulfur oxides, no volatile organic compounds, no
  particulate matter
• Mining is safer than (underground) coal mining
• Very successful in France, where it supplies 73
  of its electricity and costs 20 - 30 less than
  generating electricity by coal
• reason government and public support

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Nuclear Power Benefits (?)

• A good possible transition fuel as fossil fuels
  become more scarce (until better renewable
  sources can be developed, recall nuclear energy
  is not renewable)
• Comment Part of the lack of success of nukes in
  the U.S. is the propaganda against it, especially
  after Three-Mile Island and Chernobyl (both of
  which were caused by human incompetence, not
  nuclear technology)

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Anti-Nuclear Propaganda
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Read The Nuclear Legacy of the Soviet Union

• P. 231, Notice how we are blamed for this too!