1. Chapter 12 Nuclear Energy

2. Overview of Chapter 12 Introduction to Nuclear Science Nuclear Fission
Pros and Cons of Nuclear Energy
Safety Issues at Power Plants
Radioactive Waste
Future of Nuclear Power

3. Introduction to Nuclear Energy
Wilhelm Röentgen:
Discovered the x-ray
First Nobel Prize in Physics – 1901
X-rays are known as Röentgen in many areas

4. Introduction to Nuclear Energy
Henri Becquerel:
Discovered radiation
Nobel Prize in Physics – 1903
Mentor of Marie Curie and shared Nobel Prize with her and her husband Pierre
SI unit (international system of units) for radiation is measured in Becquerels (Bq)

5. Introduction to Nuclear Energy
Marie Curie
Discovered radiation
Created the name
Isolated isotopes
Discovered radioactive elements
Polonium named after her native land of Poland

6. Introduction to Nuclear Energy
First woman to be awarded the Nobel Prize
Only woman to be awarded the Nobel Prize in two different fields AND only person for two different sciences
1903 Physics
1911 Chemistry

7. Introduction to Nuclear Energy
Ernest Rutherford
Father of Nuclear Physics
Postulated a charged, small nucleus
Discovered and named the proton
Discovered Half-Life
Alpha and Beta Particles
Nobel Prize – Chemistry 1908

8. Introduction to Nuclear Energy
Albert Einstein
Father of Modern Physics
Nobel Prize for Physics – 1921
1905 the world’s most famous equation
E = mc2
What was the significance of this equation for nuclear energy?

9. Introduction to Nuclear Energy
Energy released by nuclear fission or fusion
Nuclear fission
Splitting of an atomic nucleus into two smaller fragments, accompanied by the release of a large amount of energy and leftover radioactive particles
Nuclear fusion
Joining of two lightweight atomic nuclei into a single, heavier nucleus, accompanied by the release of a large amount of energy.
Two H atoms making a He atom inside a star
No leftover radioactive particles created

10. Atoms and Radioactivity
Nucleus -- Mass of the atom
Comprised of protons (+) and neutrons (neutral)
Proton 1835 times more mass than electron
Electrons (–) orbit around nucleus
Mass of electron is negligible
Bohr Planetary shell model – 2,8,8,18,18,32,32
Neutral atoms
Same # of protons and electrons

11. Atoms and Radioactivity
Atomic mass
Sum of the protons and neutrons in an atom
Carbon protons and 6 neutrons
Carbon protons and 8 neutrons
Atomic number
Number of protons per atom
Each element has its own atomic number
Isotope
any of two or more forms of a chemical element, having the same number of protons in the nucleus, or the same atomic number, but having different numbers of neutrons in the nucleus, or different atomic weights.
Protium (H-1) 1 proton Deuterium (H-2) 1 proton 1 neutron
Tritium (H-3) 1 proton 2 neutrons

12. Radioactive Isotope Unstable isotope Radioactive Decay
Emission of energetic particles or rays from unstable atomic nuclei
Alpha particle – 2 protons + 2 neutrons (AM = 4)
Beta particle – free roving electron
Gamma ray – EM energy of high frequency
and short wavelength
Example
Uranium (U-235) decays over time to lead (Pb-207)
Each isotope decays based on its own half-life

13. Radioactive Isotope Half-lives
Half-Life percentages
1 HL – ½ radioactive
2 HL – ¼ radioactive
3 HL – 1/8 radioactive
4 HL – 1/16
5 HL – 1/32
6 HL – 1/64
10 HL – 1/1024
Carbon 14 has Half-Life of
5700 years.
Why is carbon dating of ancient life only good for about 50,000 years?

14. Nuclear Fission Nuclear Fuel Cycle
processes involved in producing the fuel used in nuclear reactors and in disposing of radioactive (nuclear) wastes
Uranium Isotope Proportions
Naturally occurring uranium is percent uranium-238, with uranium-235 (the energy producing isotope) making up about percent, and uranium-234 filling in the remainder at less than percent.

15. Nuclear Fission

16. How Electricity is Produced

17. Breeder Nuclear Fission
A type of nuclear fission in which non-fissionable U-238 is converted into fissionable Pu-239

18. Pros and Cons of Nuclear Energy
Less of an immediate environmental impact compared to fossil fuels
Carbon-free source of electricity
May be able to generate H-fuel
Cons
Generates radioactive waste
Many steps require fossil fuels (mining and disposal)
Expensive

19. Pros and Cons of Nuclear Energy

20. Cost of Electricity from Nuclear Energy
Cost is very high
20% of US electricity is from Nuclear Energy
Affordable due to government subsidies
Expensive to build nuclear power plants
Long cost-recovery time
Fixing technical and safety issues in existing plants is expensive

21. Safety Issues in Nuclear Power Plants
Meltdown
At high temperatures the metal encasing the uranium fuel can melt, releasing radiation
Probability of meltdown is low
Public perception is that nuclear power is not safe
Sites of major accidents:
Three Mile Island
Chernobyl (Ukraine)
Fukushima (Japan)

22. Three-Mile Island 1979 - most serious reactor accident in US
50% meltdown of reactor core
Containment building kept radiation from escaping
No substantial environmental damage
No human casualties
Elevated public apprehension of nuclear energy
Led to cancellation of many new plants in US

23. Chernobyl 1986 - worst accident in history 31 confirmed deaths
Numerous cancers and deformities after
1 or 2 explosions destroyed the nuclear reactor
Large amounts of radiation escaped into atmosphere
Highly radioactive today with large solid mass (Elephants foot) still hot today
Spread across large portions of Europe

24. Chernobyl
Radiation spread was unpredictable and uneven

25. Nuclear Energy and Nuclear Weapons
31 countries use nuclear energy to create electricity
These countries have access to spent fuel needed to make nuclear weapons
Safe storage and handling of these weapons is a concern

26. Radioactive Wastes Low-level radioactive waste
Radioactive solids, liquids, or gases that give off small amounts of ionizing radiation
High-level radioactive waste
Radioactive solids, liquids, or gases that give off large amounts of ionizing radiation

27. Radioactive Wastes Long term solution to waste
Deep geologic burial – Yucca Mountain
As of 2008 site was shut down by order of President Obama
Possibilities:
Above ground mausoleums
Arctic ice sheets
Beneath ocean floor

28. Radioactive Waste Temporary storage solutions
In nuclear plant facility (require high security)
Under water storage
Above ground concrete and steel casks
Need approved permanent options soon.

29. Operation Smash Hit Video
Click the link below to be taken to the Operation Smash Hit video
Operation Smash Hit Video

30. Case-In-Point Yucca Mountain
70,000 tons of high-level radioactive waste
Tectonic issues have been identified

31. Decommissioning Nuclear Power Plants
Licensed to operate for 40 years
Several have received 20-year extensions
Power plants cannot be abandoned when they are shut down
Three solutions
Storage
Entombment
Decommissioning (dismantling)

32. Attitudes Towards Nuclear Power
NIMBY - Not In My BackYard
Citizens to not want a nuclear facility or waste disposal site near their home
Dad- Decide, Announce, Defend
Pronuclear advocates
Based on the science, not fears

33. Fusion
Fuel= isotopes of hydrogen

34. Fusion Way of the future? Problems
Produces no high-level waste
Fuel is hydrogen
Problems
It takes very high temperatures (millions of degrees) to make atoms fuse
Confining the plasma after it is formed
Scientists have yet to be able to create energy from fusion