1. Chapter 20: Nuclear Energy

2. Alternatives to Fossil Fuels
80% of the global energy comes from fossil fuels
We need to switch to non-fossil fuel resources because
They will run out
They will become very expensive
Petrodictatorships

3. Alternatives to Fossil Fuels

4. Alternatives to Fossil Fuels
Alternatives have been developed
Still remain more expensive since the TRUE cost of fossil fuels is not factored into the market price
Technology not fully developed

5. Alternatives to Fossil Fuels
Nuclear power, biomass energy, and hydropower are conventional alternatives
Have less environmental impact than fossil fuels, but more than “new alterative” energy
Best viewed as intermediates – bridge to all “new” renewable energy

6. Alternatives to Fossil Fuels
Conventional alternatives provide some of our energy and much of our electricity

7. Nuclear Power Benefits Drawbacks No atmospheric pollutants
“fuel” only needs to be added on a yearly or biyearly basis
Drawbacks
Radioactive waste disposal
Accidents are rare, but can be VERY bad
Uranium – the fuel – is nonrenewable

8. Nuclear Power
France is often thought of as a leader in nuclear power since such a large % of their electricity is created by nuclear power plants

9. Nuclear Power - Fission
Nuclear Energy – transforming the “strong nuclear force” (the force that holds protons and neutrons together in an atom) into thermal energy to turn a turbine and generator.

10. Nuclear Power - Fission

11. Nuclear Power – Fission
Nuclear Power Plant – controlled chain reaction
Nuclear Bomb – uncontrolled chain reaction

12. Nuclear Power – Enriched Uranium
99% of the uranium in the world is U-238, but this cannot sustain a chain reaction
We use U-235 in our nuclear reactors.
Fuel rods are made from uranium that has been enriched to 3% U-235

13. Nuclear Power – Generating Electricity

14. Nuclear Power – Generating Electricity
A moderator (water or graphite) is used to slow the neutrons
Control rods are used to soak up extra neutrons to slow down the chain reaction. They can be placed all the way down to stop the reaction

15. Nuclear Power – Breeder Reactors
Benefits
Use U-238 as the fuel
Far more power, far less waste
Drawbacks
More dangerous – use liquid sodium
More expensive
Can be used to make plutonium for nuclear weapons

16. Nuclear Power – Breeder Reactors

17. Nuclear Power - Fusion

18. Nuclear Power - Fusion The process that goes on in our Sun.
Must be done at very high temperatures and pressures in order to overcome the repulsion of the nuclei

19. Nuclear Power - Fusion

20. Nuclear Power - Fusion
Still very theoretical – no commercial plants in use.
Prototype being build in France (ITER)

21. Nuclear Power – Cleaner than Fossil Fuels
Little to no air pollutant and greenhouse gas emissions
Less fuel needed means less mining

22. Nuclear Power – small risk/large accidents
Three Mile Island – Pennsylvania – 1979
Meltdown – coolant water drained, temp rose, melted some of the uranium fuel rods
Radiation contained in containment structure

23. Nuclear Power – small risk/large accidents

24. Nuclear Power – small risk/large accidents
Chernobyl – Ukraine – 1986 – USSR
Safety systems off, human error, poor design
Explosion – clouds of radioactive debris
10 days before surrounding towns evacuated
31 direct deaths, thousands effected

25. Nuclear Power – small risk/large accidents

26. Nuclear Power – small risk/large accidents

27. Nuclear Power – small risk/large accidents

28. Nuclear Power – small risk/large accidents

29. Chernobyl Legacy

30. Nuclear Power – Waste Disposal
Spend fuel rods and any equipment in the reactor
Stays radioactive for thousands of years
Must be put in a stable environment
Currently, most stored at Power Plants

31. Nuclear Power – Waste Disposal
Yucca Mountain

32. Nuclear Power – Waste Disposal

33. Nuclear Power – Waste Disposal

34. Nuclear Power – Multiple Problems slowed growth
Very expensive to build and very expensive to dismantle
Western Europe decreasing capacity
Asia increasing capacity
USA???