1. Nuclear Energy

2. Why nuclear? Power shortages Rising prices Emissions of gases
Running out of oil
Good option??

4. Brief History of Nuclear Power In The USA
US Utility Companies Begin Development in late 1950s
Support From Government:
Atomic Energy Commission
Subsidies
Government Assumes Liability
Slow/No Growth in US in Last 30 Years – fear based
103 Plants in US Generate About 21% of Electricity
This May Change…. (decreasing use)
Worldwide, 441 plants, 32 under construction. 17% of world’s energy

6. Nuclear Power Plants in the United States

7. Some Definitions….
*Fission: a large atom of one element is split to produce two different smaller elements (uranium -> by products, neutrons and energy)
Fusion: two small atoms combine to form a larger atom of a different element (Hydrogens -> Helium + energy and neutron)
Isotope: different (mass number) forms of the same element (uranium 235, 238 – differ in neutrons, same proton and electron #)

8. How Fission Works

9. Nuclear Fuel
Of the two Uranium isotopes, U-235 readily undergoes fission
Fuel for reactor
Enriched Uranium (separating isotopes to choose for U-235
4% enrichment (4% U-235, 96% U-238 to prevent amplification of explosion)
Highly enriched = spontaneous fission

12. The Light Water Nuclear Reactor
Fuel rods: rods full of 235U pellets
Moderator: fluid (water) coolant that slows down neutrons so neutrons are traveling at the right speed to trigger another fission rxn. Get hot during reactions.
Control rods: (boron or cadmium) moderate rate of the chain reaction by absorbing neutrons

13. In the Core

14. Comparing Nuclear vs. Coal Power Plants
Ample Supply
Ample Uranium Supply
Low Net Energy Yield
High Net Energy Yield
Very High Air Pollution
Low Air Pollution
High CO2 Emissions
Low CO2 Emissions
High Land Disruption
Low Land Disruption
High Land Use
Moderate/Low Land Use
Low Cost
High Cost
Base Load Power – best comparison is nuclear vs. coal

15. Comparing Coal and Nuclear Power

16. Concerns With Nuclear Power
Radioactive emissions
Radioactive wastes
Disposal of radioactive wastes
Nuclear power accidents
Safety and nuclear power
Economic problems with nuclear power

17. Some Definitions:
Radioisotopes: unstable isotopes of the elements resulting from the fission process
Radioactive emissions: subatomic particles (neutrons) and high-energy radiation (alpha, beta, and gamma rays)
Radioactive wastes: materials that become radioactive by absorbing neutrons from the fission process

19. Radiation is Everywhere – Nuclear Power is Not the Only Source (or even a Major Source)
Television
Household Radon
Airplane Flights
Emissions From Coal Power Plants
Medical X-Rays
Radon

20. Radioactive Decay

22. What to do with the waste?
It Depends….
Waste could be spent fuel rods
Waste could be dismantled reactor parts
Two Stages:
Short-term containment (short-lived isotopes decay to a point where they are easier to deal with)
Long-term containment (10000 year minimum!)

23. What to do with the waste?
Siting (NIMBY)
Transport
Cost ($60 billion to 1.5 trillion)
Yucca Mountain in southwestern Nevada = the nation’s nuclear waste repository (operational in 2010? Or 2015 Or NEVER)

24. Nuclear Accidents –Three Mile Island
United States: Three-mile Island
1979
Harrisburg, PA
Loss of coolant in reactor vessel
Damage so bad, reactor shut down permanently
Unknown amount of radiation released into atmosphere

25. Nuclear Accidents – Chernobyl
Loss of water coolant perhaps triggered the accident. When the water-circulation system failed, the temperature in the reactor core increased to over 5,000 oF, causing the uranium fuel to begin melting and producing steam that reacted with the zirconium alloy cladding of the fuel rods to produce hydrogen gas.
A second reaction between steam and graphite produced free hydrogen and carbon oxides. When this gas combined with oxygen, a blast blew off the top of the building, igniting the graphite. The burning graphite threw a dense cloud of radioactive fission products into the air.

26. Kidd of Speed