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