Nuclear Energy Chapter 12

Introduction to the Nuclear Process Fission – nuclear energy released when atom split Fusion – nuclear energy released when atoms fused

Introduction to the Nuclear Process Atoms and Radioactivity Proton (+) Neutron (0) Electron (-) Nucleus Normally: # protons = # 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

Introduction to the Nuclear Process 6 P 8 N Carbon If actual atomic mass > normal atomic mass  typically caused by greater number of neutrons Results in an isotope Chemical behavior identical to normal atom. Many are radioactive

Common Radioactive Isotopes Introduction to the Nuclear Process Insert Table 12.1

Nuclear Fission Nuclear 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 Insert Fig 12.4

Nuclear Fission How Electricity is Produced from Conventional Nuclear Fission Insert Fig 12.5

Nuclear Fission Breeder Nuclear Fission Insert Fig 12.6

Pros and Cons of Nuclear Energy Impact CoalNuclear Land use 17,000 ac1,900 ac Daily fuel requirement 9,000 tons/day3 kg/day Air pollution Moderate to severe Low Radioactive emissions 1 curie28,000 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 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 Chornobyl Insert Fig 12.7

Safety Issues in Nuclear Power Plants Radioactive fallout from Chornobyl: Insert Fig 12.8

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 Wastes Two general types: Low-level radioactive wastes High-level radioactive wastes Insert Table 12.3

Radioactive Wastes Temporary storage includes above-ground storage casks Insert Fig a, b

Radioactive Wastes Case-in-Point: Yucca Mountain Insert Fig b

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 Insert 12.12

The Future of Nuclear Power Issues: Making nuclear power safer Standardizing power plant designs