Nuclear Power

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Nuclear Power

• ES 302

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Nuclear Trivia

• Utilities develop in 1950s
• Atomic Energy Commission promised utilities
  cheap electricity
• Govt pay ¼ building cost
• Price Anderson Act
• Liability protection
• By 96 govt subsidized 2T

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437 commercial reactors in 32 countries,
producing 17 electricity
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www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Nuclear Energy

• The energy that exists within the nucleus of an
  atom.
• Nuclear Fission the release of energy from the
  splitting of atoms!
• Nuclear Fusion the combining of two smaller
  atoms into one larger atom.
• http//videos.howstuffworks.com/hsw/11945-nuclear-
  energy-introduction-to-nuclear-energy-video.htm

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Nuclear Fission
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Nuclear Fusion
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Nulear Change

• Nuclear Fission

• Nuclear Fusion

• Bombs power plants
• Big, unstable isotopes are struck by neutrons,
  which splits the isotopes nuclei
• More neutrons shoot out to strike nearby
  isotopes, causing a chain reaction.

• Sun and stars, some weapons
• 2 small (light) isotopes are forced together
• H H He
• Need temps gt 100,000,000ºC
• Releases more E than fission

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When people think about nuclear power they think
about

1. Effects of radiation
2. Nuclear disasters
3. Nuclear waste disposal

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What is Radiation?

• Radiation particles given off by unstable
  atoms.
• 3 Types
• Alpha (a)
• Travels few inches
• Blocked by paper (skin)
• Beta (ß)
• Travels few feet
• Blocked by aluminum, glass
• Gamma (?)
• Travels far
• Blocked by lead (steel concrete).

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www.geology.fau.edu/course_info/fall02/
EVR3019/Nuclear_Waste.ppt
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Background Radiation

• The amount of radiation we are exposed to daily
  from the environment
• Average
• 360 millirem/year

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Effects of Radiation

• Genetic damages from mutations that alter genes
• defects can become apparent in the next
  generation
• Somatic damages to tissue, such as burns,
  miscarriages cancers

www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Nuclear Power Plant

• a controlled nuclear fission chain reaction
• heats water
• produce high-pressure steam
• that turns turbines
• which turns generator and creates electricity.
• http//www.howstuffworks.com/nuclear-power2.htm

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Controlled Nuclear Fission Reaction
cstl-cst.semo.edu/bornstein/BS105/
Energy20Use20-203.ppt
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• http//www.animatedsoftware.com/environm/nukequiz/
  nukequiz_one/nuke_parts/reactor_parts.swf

www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Nuclear Reactor Summary

• Core
• 35-40,000 fuel rods
• Uranium oxide pellets
• 97 U238 (nonfissionable), 3 U235
• Control rods
• Absorb neutrons
• Moderator
• Slows down neutrons, maintains chain rxn.
• Water 75, solid graphite 20, heavy water
  (D2O) 5
• Coolant
• Transfers heat to steam lines
• Prevents meltdown

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Nuclear waste

• Power plants produce radioactive wastes
• mostly spent fuel rods (3-4 years)
• each reactor produces about 20-30 tons yearly
• Currently stored in pools on site
• some remain dangerous for tens of thousands of
  years
• How should we store this waste?

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Half-Life
time needed for one-half of the nuclei in a
radioisotope to decay and emit their radiation to
form a stable isotope Half-time emitted
Uranium 235 710 million yrs alpha,
gamma Plutonium 239 24.000 yrs alpha, gamma
www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Decommissioning

• Life span of a power plant 15-40 years
• Parts wear out, Fuel is spent
• Plant is shut down
• Highly radioactive for 240,000 years
• Must store for 10 times the half-life
• What can we do with them?

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Low-Level High Level Radioactive Waste

• Emit small amounts of ionizing radiation
• Stored 100-500 years
• 1940?1970 put in steel drums, dumped in ocean
  (still UK Pakistan)
• 1970 govt run landfills

• Stored for thousands of years
• Mostly spent fuel rods (240,000 yrs)
• Safety debate
• Options
• Keep onsight
• Bury
• Shoot into space
• Bury in ocean floor
• Bury in Antarctica
• Change it into harmless

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Renewable or Non-Renewable?
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(No Transcript)
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What do you think?

• What are the pros and cons for nuclear energy?
• What should we do with radioactive waste?

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Nuclear Reactor

• Domed building
• Where nuclear fission occurs.
• Surrounded by thick concrete, steel lead.
• Blocks all radiation!

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Inside the Reactor

• Fuel Rods
• 35,000 70,000 fuel rods
• 3 Uranium-235 pellets
• In water (moderator)
• Control Rods
• absorb extra neutrons
• Control the chain reaction

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Cooling Tower

• Water is the coolant in the system.
• Tower is used to condense hot steam to liquid
  water.
• Usually taken from river, lake, ocean.
• Water can be reused.

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• http//streaming.discoveryeducation.com/search/ass
  etDetail.cfm?guidAssetIDBE0FB49C-7C70-4C56-95F2-B
  3904BC9077F
• 10 min video on nuclear energy
• Fission, fusion, overview

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Uranium 92U238.02891
How many protons? How many electrons? How many
neutrons?
6 C Carbon 12.011
92 protons 92 electrons 146 neutrons
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NUCLEAR CHANGE

• Isotopes ? vary by number of neutrons
• Spontaneously undergo change (vary neutrons)
• 3 types radioactive decay
• nuclear fission
• nuclear fusion

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Radioactivity

• Radioactivity Nuclear changes in which unstable
  (radioactive) isotopes emit particles energy
• Radioactive decay continues until
• original isotope (radioisotope) ?stable isotope

www.bio.miami.edu/beck/esc101/Chapter1415.ppt
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Radioactive Decay

• Emits high energy radiation /or particles
• Gamma radiation
• Alpha particles
• Beta particles
• The isotopes shoot out these particles, forming
  different isotopes
• The rate this change occurs at half-life