1. ENERGY
NUCLEAR POWER

2. The Energy Of Atomic Fission
Definitions
Proton - a positively charged subatomic particle
Neutron - a negatively charged subatomic particle
Isotope - atom that exhibits variation in its mass number
Mass number - sum of the neutrons plus the protons in an atom
Atomic number - # of protons found in the nucleus
Atomic weight - average of the atomic masses of all the element's isotopes
Fission - the act or process of splitting into parts
Fusion - a nuclear reaction in which nuclei combine to form more massive nuclei with the simultaneous release of energy

3. The Energy Of Atomic Fission
Fuels for Nuclear Reactors
Natural fuels
U235 is the only natural isotope of any element that is spontaneously fissionable
92U % of all U
92U %
92U %
U235 is the initial fuel for all fission reactors
1 gram of U235 equals 2.7 metric tons coal or 13.7 bbls oil

4. The Energy Of Atomic Fission
Fuels for Nuclear Reactors
Man made fuels
U238 and Th232, fertile materials, can be made to combine with a neutron to make a useful fuel
92U238 + neutron → 94Pu239 fuel
90Th232 + neutron → 92U233 fuel

5. The Energy Of Atomic Fission
The Nuclear Fuel Cycle
U235 must be enriched from 0.711% to 3.0%
This is done with UF6 gas
After enrichment the U is made into UO2 ceramic pellets
These pellets become fuel rods which last 3 years
They are then stored in water at the reactor site

6. The Energy Of Atomic Fission
Types of Reactors
The Light Water Reactor LWR
This is a burner type reactor which simply consumes U235 and produces neutrons, heat, and waste
Reactor ultimately produces steam to drive the turbine
A typical LWR has 100 tons of enriched U fuel - 40,000 rods
Control rods are neutron absorbing B or Cd

7. The Energy Of Atomic Fission
Types of Reactors
Breeder Reactors
These reactors convert U238 and Th232 into fuel
France, Japan, the United Kingdom, Germany and the USSR are developing breeders
The United States started research in 1948 on the LMFBR
Low U costs will probably delay breeders in the U.S. until after 2000

8. Problems Of Uranium Mining
Lung Cancer among the Miners
NRC and the U.S. Public Health Service found a higher incidence of lung cancer among miners
Waste from Uranium Milling
865 gallons of toxic chemical waste form per ton of ore treated
This waste was discharged into rivers or seeped into the Earth in the 1960's

9. Problems Of Uranium Mining
The Problem of Tailings
100 million tons of radioactive sand exists at 30 mills in the western U.S.
5000 homes in Grand Junction, CO were built with this sand
Tailings have washed into Lake Powell and Lake Meade

10. Problems At The Reactor Site
Geological Problems
Extremely extensive geological investigations are made
Reactors still end up too close to fault zones
Diablo Canyon - PG&E
Bodega Bay

11. Problems At The Reactor Site
Human and Mechanical Error
Three Mile Island - March 28, 1979
The feed water pump to the reactor core was accidentally closed
rods immediately went in and the reactor partly stopped
Human error resulted in the emergency cooling system being shut off for 2 hours
Core overheated to 1500ºC
one billion dollars damage

12. Problems At The Reactor Site
Human and Mechanical Error
Chernobyl - April 26, 1986
Human errors resulted in a explosion and radiation release
100,000 people may be contaminated

13. The Disposal Of Nuclear Waste
What the Waste Products are
Fission products
Over 30 elements form
most have half lives of <100 years
emit beta and gamma radiation
Some are water soluble and biologically active
Transuranium products
heavier than U and form by neutron capture
have half lives >1000 years
act as heavy metal poisons
Waste must be stored for 250,000 years

14. The Disposal Of Nuclear Waste
How Much Spent Nuclear Fuel is there in the U.S.A.
Remember that there is also military and medical waste
By the year 2000 there will be 40,000 metric tons stored at 70 locations
By 2035 the total will be 85,000 metric tons
The Nuclear Waste Policy Act of 1982 selected Yucca Mountain, NV as the only depository site in the U.S.

15. The Disposal Of Nuclear Waste
Criteria for a Storage Method
isolation from the biosphere for 250,000 years
sabotage and accident free for 250,000 years
safe from natural disasters for 250,000 years
must not involve large land areas or resources
must be resistant to erosion, Earthquakes, and volcanism
handling and transport must be fail safe
economically and technically possible

16. The Disposal Of Nuclear Waste
Possible Storage Methods
Rocket transport of the waste
dangerous and costly
Continue present tank storage indefinitely
leakage of dangerous waste has already occurred
Placement in deep chambers of granite
waste would boil, dehydrate, melt the surrounding rock and seal itself
leakage along fractures is possible

17. The Disposal Of Nuclear Waste
Possible Storage Methods
Injection in Deep Wells
Waste would be mixed with cement or injected directly under high pressure into impermeable layers
Many dangers
high pressure injection is dangerous
high temperature could drive the waste out into other layers
could lubricate faults
Deposition in Trenches
technically difficult to assure no leaks

18. The Disposal Of Nuclear Waste
Possible Storage Methods
Deposition under polar ice caps
Waste containers melt to the bottom of the glacier and remain stationary
Violates international treaties
Salt Mine Waste Storage
salt indicates a dry environment
salt flows and seals fractures
salt dissipates heat
Element Transmutation
Eventually gamma ray lasers will convert dangerous elements into safe ones

19. The Disposal Of Nuclear Waste
What is to be done?
Find a public repository for nuclear waste
Because of public fear this is probably a doomed and costly effort
Reprocess spent fuel to reduce the volume of waste
This raises more fear because Pu may be diverted to nuclear weapons
A permanent repository will still be needed

20. The Disposal Of Nuclear Waste
What is to be done?
Continue on-site, dry-tank storage
This is the only reasonable political solution
This can be done for a 100 years and will allow time for:
improved technology
decline of public fear