1. Nuclear Energy David Rude
Unit 7 – Chapter 9, Part 2
Nuclear Energy
David Rude

2. Non-Renewable Energy Sources
Diablo Canyon Nuclear Power Plant

3. Outline 9.5 Nuclear Power 9.6 The Nature of Nuclear Energy
9.7 Nuclear Chain Reaction
9.8 Nuclear Fission Reactors

4. Outline 9.9 The Nuclear Fuel Cycle
9.10 Issues Related to the Use of Nuclear Fuels

5. 9.5 Nuclear Power Nuclear power is fueled by uranium
Obtained from mining
Non-renewable.
Word energy sources in order of importance:
Oil
Coal
Natural gas
Hydroelectric
Nuclear
Fifth most important

6. 9.5 Nuclear Power Main reasons for opposing nuclear power:
Threat to world peace
This group opposes all things nuclear
Environmental concerns due to potential nuclear contamination
Problem of waste disposal

7. 9.5 Nuclear Power Two reasons for renewed interest
The threat of climate change
Does not produce carbon dioxide
Many now see it as a continuing part of the energy equation
Economics
Increased cost of oil and natural gas makes nuclear more attractive

8. 9.5 Nuclear Power World’s energy production:
14% of world-wide electrical output
5½% of all power consumed

9. 9.5 Nuclear Power As of 2011 440 nuclear power reactors in operation
61 under construction in 13 countries
169 nuclear power plants currently planned
Most in Asian countries
Breakdown:
85 in China, India, Japan and South Korea
14 in Russia
7 in US

10. 9.5 Nuclear Power
19 Countries get 20% or more of electricity from nukes
US – 20%
Japan – 30%
France – 75%
Original operation licenses were for 40 years
Most are being extended to 60 years
Delays decommissioning for 20 years
No new plants needed to replace lost capacity

12. 9.6 The Nature of Nuclear Energy
Atoms
Basic building blocks of matter
Element
Cannot be divided into any other type of matter
Oxygen, carbon, hydrogen, iron, and aluminum
90 naturally occurring kinds
25 types made by scientists

13. 9.6 The Nature of Nuclear Energy
Compound
Matter made up of two or more types of atoms
Examples
Water, steel, oil, plastic

14. 9.6 The Nature of Nuclear Energy
Three basic parts
Protons – positive charge
Neutrons – no charge
Electrons – negative charge
Heald together by
Nuclear force

15. The Nature of Nuclear Energy
Radioactive
Nuclei of certain atoms are unstable and spontaneously decompose (break apart)
Neutrons
Electrons
Protons
Other larger particles
Great deal of energy

16. When atoms decay and release particles
Become a different type of atom
Example: U-238

17. The Nature of Nuclear Energy
Radioactive Half-Life
Time it takes for half the radioactive material to spontaneously decompose
Isotope:
An atom with the same number of protons, but different numbers of neutrons
Isotopes are different forms of a single element.

18. The Nature of Nuclear Energy
Carbon
C12 – 6 Protons, 6 Neutrons
Stable
98.8%
C13 – 6 Protons, 7 Neutrons
1.1%
C14 – 6 Protons, 8 Neutrons
Unstable – 5,730 year half-life
Years
Amount
1 g
5,730
0.5 g
11,460
0.25 g
17,190
0.125 g
C14 Half Life

19. The Nature of Nuclear Energy
Iodine
37 known isotopes
I-127 is only stable isotope
53 Protons
74 Neutrons
Iodine-131
78 Neutrons
Used in Medicine
8 day half-life
Emits beta radiation (electrons)
Days
Amount
4 mCi 8
2 mCi 16
1 mCi 32
.5 mCi
Dental X-Ray =
2-3 millicuries

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21. p. 215

22. The Nature of Nuclear Energy
Radiation
Energy released from the nucleus during nuclear disintegration
Three basic types of radiation
Alpha
Two neutrons and two protons
Stopped by sheet of paper
Beta radiation
Electrons
Stopped by layer of clothing, glass or aluminum

23. The Nature of Nuclear Energy
Gamma radiation
Electromagnetic radiation

25. The Nature of Nuclear Energy
Nuclear fission
Neutrons hit and split the nuclei of certain other atoms
Fissionable
Atoms that can split easily
Nuclear chain reaction
Splitting nuclei release neutrons
These strike more nuclei releasing more neutrons
Cascading effect

26. The Nature of Nuclear Energy
Nuclear fission chain reaction

27. The Nature of Nuclear Energy
Atoms suitable nuclear chain reaction
Two most common
Uranium-235
Plutonium-239.
Must be a certain quantity of nuclear fuel (critical mass)

28. 9.8 Nuclear Fission Reactors
Nuclear reactor
A device that permits a controlled fission chain reaction
U-235 is fuel
Fissionable: element whose nucleus will split apart

29. The Nature of Nuclear Energy
Nuclear fission chain reaction

30. Nuclear Fission Reactors
Control rods
Made of a non-fissionable material (boron, graphite)
Absorb neutrons to control rate of fission
Rate slows when inserted
Rate increases when withdrawn
Moderator
Substance that absorbs energy
Slows neutrons
Enables them to split the nuclei of other atoms more effectively

31. Nuclear Fission Reactors
Core coolant
Material used to transfer heat away from the core
Prevents overheating and melting of reactor casing
Usually water

32. Nuclear Fission Reactors
A nuclear reactor serves the same function as a fossil-fuel boiler
Produces heat
Heat converts water to steam
Steam turns a turbine
Turbine spins a giant coil of wire between to large magnets

35. Nuclear Fission Reactors
Three most common types of reactors
20% Boiling-Water
60% Pressurized-Water
10% Heavy-Water
Uses Deuterium
Hydrogen stable isotope (1 proton, 1 neutron)
Boils at higher temperature
Gas-Cooled Reactors are not popular
No new plants being constructed

36. Nuclear Fission Reactors
Boiling-water reactor
Steam forms in reactor and turns turbine
Disadvantages
Steam must be treated to remove any radiation
Some radioactive material is left in the steam
Generating building must be shielded

37. Nuclear Fission Reactors
Boiling water reactor

38. Nuclear Fission Reactors
Pressurized water reactor
Water is pressurized so it doesn’t form steam
Secondary loop transfers the heat from the pressurized water in the reactor to a steam generator.
Advantages/Disadvantages
Less waste radiation
Increased costs of construction
Easier maintenance due to radiation being contained

39. Nuclear Fission Reactors
Pressurized-water reactor

40. Nuclear Fission Reactors
Heavy-water reactor
Basically same as Pressurized Water Reactors
Uses water with deuterium instead of regular hydrogen
Normal Hydrogen: one Proton and Electron – no neutron
Deuterium: one proton, neutron and electron
A stable isotope of hydrogen
Not radioactive

41. Nuclear Fission Reactors
Advantages
Heavy water is a better moderator than regular water
Moderator slows free neutrons
more efficient at splitting nuclei
Cheaper to run since it can use regular uranium
Uses naturally occurring U-238 instead of enriched U-235

42. 9.8 Nuclear Fission Reactors
Breeder reactors produce nuclear fuel as they produce electricity.
Liquid sodium efficiently moves heat away from the reactor core.
Hence they are called Liquid Metal Fast Breeder Reactors.
A fast moving neutron is absorbed by Uranium-238 and produces Plutonium-239
P 239 is fissionable fuel.
Most breeder reactors are considered experimental.
Because P239 can be used in nuclear weapons, they are politically sensitive.

43. Investigating Nuclear Alternatives
Breeder reactors
Produce nuclear fuel as they produce electricity
Plutonium
Requires fast moving neutrons
Cannot use water as a moderator
Lots of heat is generated
Uses liquid metal as core coolant
Usually sodium
Also called Liquid Metal Fast Breeder Reactors
Most considered experimental

44. Investigating Nuclear Alternatives
Formation of Pu-239 in a breeder reactor

45. Investigating Nuclear Alternatives
Problems
Produce Plutonium-239
Very hazardous to humans
Can be used in nuclear weapons
Very dangerous to operate
If liquid sodium boils it can damage reactor and lead to a nuclear accident.
Liquid sodium must be at 620oC so it requires very specialized equipment.
When shut down sodium becomes a solid

46. Investigating Nuclear Alternatives
Can be difficult to operate because the reaction occurs so rapidly
Most have been shut down
Currently
Only operating in Russia, China, & Japan
Russia and India plan to build new ones

47. Investigating Nuclear Alternatives
Nuclear fusion
Two lightweight atomic nuclei combine to form a heavier nucleus
Releases large amount of energy
Fusion occurs in stars like our sun.
Currently not possible provide a reliable source of energy with fusion
Governments provide little funding for fusion research