1. Chapter 16/17 RAD Guide
April 21, 2017

2. NUCLEAR ENERGY

3. Atomic Model s

4. Atomic Model (cont) Atomic consists of:
Protons ( + charge)
Nuetrons (neutral charge)
Electrons (- charge)
Protons and neutrons makes the nucleus
Majority of atomic mass is in the nucleus
Electrons orbit the nucleus

5. Atomic Number & Mass Number
Atomic number: the number of protons in an atom.
Example: if oxygen has 8 protons, what is oxygen’s atomic number?
Mass number: the number of protons plus the number of neutrons in an atom.
We neglect electrons for mass number because mass of electrons is negligible.

6. Isotopes s

7. Isotopes (cont)
Atoms of the same element that have different numbers of neutrons are called isotopes.
This means that isotopes of the same element will have different mass numbers.
Note: the number of protons in isotopes are always the same.

8. Radioactivity
Unstable atoms decay, emitting particles and energy from the nucleus.
After a series of decay changes, a radioactive element becomes stable.

9. Types of Particles Emitted from Unstable Nuclei (Radiation)
Alpha particles (α): decay that gives off 2 protons and 2 neutrons
Beta particles (β): decay that gives off an electron, converting a neutron into a proton
Gamma (γ) radiation: form of electromagnetic radiation. A large burst of energy.

10. Question Do these emissions alter an element’s … Atomic number?
Mass number?

11. Half-Life
The amount of time it takes for half of the atoms in a sample of radioactive material to decay.

12. Reactions and Reactors

13. Nuclear Fission
Energy holds the protons and neutrons in an atom’s nucleus together.
Question: what would happen if we were to split the nucleus of an atom apart?

14. Nuclear Fission: Reaction in which the nucleus of a large atom is split into smaller nuclei.

15. Uranium -235 Chain Reaction
most commonly used in nuclear reactors.

16. Structure & function of nuclear power plant.
Fission of U-235 in reactor vessel  heats H2O  steam  turns turbines  energy stored in generator  used as electricity
Water circulates between fuel rods, acting as a coolant and slowing neutrons.
control rods control how fast or slow reaction occurs

17. Nuclear Power Plant

18. Breeder Reactors

19. Radioactive Waste Harmful to living organisms
Immediate effect: skin burns, anemia, death
Long term effect: changes in DNA, leading to cancer & genetic mutations

20. Radioactive Waste High-level wastes Medium/Low-level wastes
Emit large amounts of radiation.
Uranium fuel rods, control rods, coolant water.
Medium/Low-level wastes
large volume of this type of waste is generated.
Most common
Effects may not be immediately noticeable.

21. Nuclear Waste Disposal
High level wastes
Stored in tanks outside power plants
Tanks often leak, leading to contaminated site.
Low/medium level wastes
Often buried
Enclosed and dropped into oceans.

22. Nuclear Waste Disposal
Issues in finding permanent disposal method:
Long half-lives
hazardous/poisonous.
Wastes must be sealed in containers that will never corrode
Containers often leak into environment
Waste sites must be geologically stable.
Deep underground storage is highly expensive.

23. Nuclear Meltdown
If the cooling and control systems in a reactor core fail, the chain reaction becomes uncontrollable and melts reactor core.

24. Nuclear Meltdown

25. Chernobyl Disaster d

26. Solar Energy d

27. The Sun Source of almost all the energy on Earth’s surface Ecosystems
Water Cycle
Causes the winds to blow

28. Ecosystems s

29. Water Cycle dd

30. Wind d

31. Thermonuclear Fusion d

32. Solar Energy
Harnessing the sun’s energy to generate heat and electricity.
Advantages
renewable, nonpolluting.
Disadvantages
Energy source is not constant
Equipment is not size and cost efficient.

33. Passive Solar Energy
Passive: sun’s energy is collected, stored, & distributed naturally in enclosed dwelling
Not used to produce electricity, but reduces the need for it.
Achieved through building design and positioning.
Ex: Greenhouse

34. Passive Solar Energy (cont)d

35. Passive Solar Energy (summary)
South facing windows
Building materials that absorb solar energy
Glass-enclosed areas
Dark colored walls and floors
Good insulation
Thick, heavy curtains or shutters.

36. Active Solar Energy
Active: devices are used to collect, store, and circulate heat produced from solar energy.
Types
Flat-plate solar collectors
Photovoltaic cells

37. Flat-Plate Solar collectorsd

38. Flat-Plate Solar Collectorsd

39. Solar One in Mojave Desert, CA.

40. Photovoltaic (PV) Cells
Only solar energy device that produces electricity directly.
Uses thin wafers of semiconductor material.
Silicon or selenium
Structure:
Two thin slices of semiconductor material joined.
Sunlight striking the cell causes electrons to move from one slice to the other, resulting in an electric current.

41. PV Cells (cont) s

42. PV Cell (cont) Uses Advantages Solar powered Calculators
Solar powered watch
Electricity for homes, industry, automobiles
Advantages
Light weight
No wastes or pollutants
No moving parts
Do not consume any materials

43. Hydroelectric Energy d

44. Dams Flowing Water Water behind dam is directed at the turbine blades
Water pushes against the turbine blades, causing them to turn. (kinetic energy to mechanical energy)
Mechanical energy of the turbine is transferred to coils within a generator
The coils spin through a magnetic field, producing sent electricity

45. Function of Dams d

46. Advantages of Dams Renewable Controls flow of water Reservoirs
Flood control
Navigation of Boats
Reservoirs
Recreation areas (fish, boat, swim)
Store water (irrigation and home use)

47. Disadvantages of Dams
Changed water depth and flow alters natural plant & animal life
Shoreline can flood, leading to erosion & change ecosystems
Fish caught in turbine blades
Prevent salmon from completing reproductive cycle
Stored water released into downstream water causes changes a rapid change in temp

48. Tidal Energy (still hydroelectricity)
High and low tides cause turbines to turn in both directions generating electricity.

49. Tidal Energy Disadvantages
In most regions, the difference between high and low tide is insufficient to power a generator
Equipment damages surrounding wetlands
Affects local ecosystems.

50. Wind Energy d

51. Aerogenerator
Windmills that are used to generate electricity (wind turbine generators)

52. Aerogenerators Winds causes blades to turn
energy is stored in generator
sent out as electricity
Types
Blades on horizontal (like airplane)
Blades on vertical (like eggbeater)
Used for calmer conditions

53. Wind Farms d

54. Advantages of Wind Power
Renewable
Free
Unlimited
nonpolluting

55. Disadvantages of Wind Power
Not always windy enough
Wins farms Require a lot of land
Interferes with radio & TV signals
Impact wildlife
Ugly (?)

56. Geothermal Energy

57. Heat Source Radioactive decay of elements deep beneath the ground.
This decay gives off heat

58. lava, geysers steam vents, hot springs, & bubbling mud.

59. Hot Rock Zones
1.Hot water is pumped from deep underground through a well under high pressure.
2.When the water reaches the surface, the pressure is dropped, which causes the water to turn into steam.
3.The steam spins a turbine, which is connected to a generator that produces electricity.
4.The steam cools off in a cooling tower and condenses back to water.
5.The cooled water is pumped back into the Earth to begin the process again.

60. Hot Rock Zones d

61. What are some advantages & disadvantages to using geothermal?
Not easy to find
Most areas have very little geothermal heat at surface, and it’s not worth extracting.
Hydrogen Sulfide gas pollutes the air.
Minerals and salts corrode pipes.
Lack local H2O supply for steam production.

62. Recall: Thermonuclear Fusiond

63. Nuclear Fusion using Deuterium

64. Nuclear Fusion
Recall: Occurs when 2 atomic nuclei fuse to become one larger nucleus
The fuel for nuclear fusion reactions is deuterium (H-2 isotope of hydrogen).
Fuel is readily available in seawater
Fusion produces much less waste than fission, and produces enormous amounts of energy
However, scientists are still learning how to harness this energy source efficiently.