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Nuclear Energy
Chapter 12
Introduction to the Nuclear Process
• Fission –
nuclear energy released when atom split,
conventional technology
• Fusion –
nuclear energy released when atoms fused, solar & futuristic
• Enrichment – Concentration of uranium ore to 3% to enable it to react
Introduction to the Nuclear ProcessAtoms and Radioactivity
Proton (+)
Neutron (0)
Electron (-)
Nucleus
Normally: # protons = # neutrons = # electrons
Atomic mass = # protons + # neutrons
Atomic number = # protons
Introduction to the Nuclear Process
8 P
8 N
Oxygen
6 P
6 N
Carbon
Differing # proton = different atom
Normally, # proton = # electrons = # neutrons
Introduction to the Nuclear Process
6 P
8 N
Carbon
If # neutrons > # protons = Isotope
Chemical behavior identical to normal atom.
Many are radioactive
Common Radioactive Isotopes
Introduction to the Nuclear Process
Nuclear FissionNuclear Fuel Cycle
Uranium mines and mills
U-235 enrichment
Fabrication of fuel assemblies
Nuclear power plant
Uranium tailings
Depleted uranium tails
Factory wastes
Low-level wastes
Spent fuel stored on-site
Deep geological disposal
Spent fuel reprocessing
Nuclear Fission
Nuclear Fission
How Electricity is Produced from Conventional Nuclear Fission
Nuclear Fission
Breeder Nuclear Fission
Pros and Cons of Nuclear Energy
Impact Coal Nuclear
Land use 17,000 ac 1,900 ac
Daily fuel requirement
9,000 tons/day 3 kg/day
Air pollutionModerate to severe
Low
Radioactive emissions
1 curie 28,000 curies
Risk from catastrophic accidents
Short-term local risk
Long-term risk over large area
Pros and Cons of Nuclear Energy
Is Electricity Produced by Nuclear Energy Cheap?
• Role of government subsidies (hidden costs)
• The cost of building a nuclear power plant
• Fixing technical and safety problems in existing plants
Pros and Cons of Nuclear Energy
Can Nuclear Energy Decrease Our Reliance on Foreign Oil?
• Only 3% of electricity in US generated by oil
• Oil primarily used for:– heating buildings
– vehicles
Safety Issues in Nuclear Power Plants
• Probability of major accident low,
but if it occurs, consequences are wide-spread and long-lasting
• Major accidents have included:
Three Mile Island - 1979
Chornobyl - 1986
Safety Issues in Nuclear Power Plants
Radioactive fallout from Chornobyl:
Safety Issues in Nuclear Power Plants
The Link Between Nuclear Energy and Nuclear Weapons
Spent fuel from conventional nuclear plant
Fuel for breeder reactor
Can be reprocessed for . . .
OR Nuclear weapons
Radioactive WastesTwo general types:
• Low-level radioactive wastes - contaminated
• High-level radioactive wastes - reactor
Radioactive Wastes
Temporary storage includes above-ground storage casks
Insert Fig 12.10 a, b
Radioactive Wastes
Case-in-Point: Yucca Mountain – by 2010
Radioactive Wastes
Other considerations:
• High-Level Radioactive Liquid Waste
• Radioactive Wastes with Relatively Short Half-Lives
• Decommissioning Nuclear Power Plants
Fusion: Nuclear Energy for the Future?
Fusion
The Future of Nuclear Power
Issues:
• Making nuclear power safer - NRC
• Standardizing power plant designs internationally