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Nuclear PowerNuclear Power
Physics 13034/7/03
Outline Outline
The NucleusRadioactivityFissionFusionNuclear WeaponsNuclear Power
NucleusNucleus
Composed of protons and neutrons
239Pu94 or Pu – 23994 protons145 neutronsIsotope of Plutonium
RadioactivityRadioactivity
Some isotopes are unstable
Spontaneously DecayDecaying isotopes emit
particles
Radon is a health hazardRadon is a health hazard
Product of the decay of naturally occurring uranium
Affects indoor air quality2nd leading cause of lung
cancerRegional issue
Half-lifeHalf-life
Pu-239 decays to U-235 with the emission of an alpha particle:
The time for half of the Pu-239 nuclei to decay is called the half-life.
24,000 years is half-life for Pu-239 decay
Aside: Pathetic JokeAside: Pathetic Joke
Did you hear about the socially sophisticated physicist?.
He was the half-life of the party.
FissionFission
By bombarding a nucleus with neutrons, a stable isotope can be induced to fission or split.
U-235 is an example of a fissionable material.
The release of neutrons in this reaction means that we can set up a chain reaction
Fission Releases EnergyFission Releases Energy
When the fission is controlled, as in a nuclear reactor, it can be a practical source of power.
When the fission is uncontrolled it can be the basis for weapons of mass destruction.
FusionFusion
Two light nuclei combine to form a heavier nucleus.
The fusion of deuterium (a hydrogen isotope) with tritium (another hydrogen isotope) to form a helium nucleus can release a great deal of energy.
Fusion PowerFusion Power
Using a fission bomb as a trigger, a hydrogen bomb, or a H-bomb uses fusion to create a WMD.
Solar energy originates as fusion energy in the sun’s interior.
Fusion power is an active area of research.
Nuclear WeaponsNuclear Weapons
First nuclear weapon tested at Trinity site in 1945 used Pu-239.
The fuel for the Hiroshima and Nagasaki bombs were U-235 and Pu-239, respectively.
First H-bomb test in 1952
Nuclear WeaponsNuclear WeaponsCountry Strategic Tactical Total
United States 7,300 3,200-4,700 10,500-12,000
Russia 6,000 7,000-15,000 13,000-20,000
China 290 120 400-410
France 400 80 400-482
United Kingdom 100 100 200
India - 85-90 85-90
Israel - 100-300 100-300
Pakistan - 15-25 15-25
Global Total - - 24,700-33,507
Nuclear Reactors:Boiling Water Reactor
(BWR)
Nuclear Reactors:Boiling Water Reactor
(BWR)Similar to coal
plant: boils water, makes steam, steam drives turbine, turbine turns electrical generator
Fissioning of U-235 is the fuel.
BWR ComponentsBWR Components
Containment building prevents release of radiation
Water is needed as coolant and to prevent meltdown.
Nuclear Reactor is a Heat Engine
Nuclear Reactor is a Heat Engine
Efficiency is similar to a coal burning plant, about 33%
So, 2/3 of the released energy is waste heat.
Uranium FuelUranium Fuel
Only 0.7% of natural U is U-235.
U-238 is not fissionable.
U must be enriched to 2.8% U-235.
Uranium Fuel SupplyUranium Fuel SupplyWorldwide U-235
resource does not offer a long-term energy solution.
Breeder reactor consuming U-235 can convert U-238 into Pu-239.
Plutonium EconomyPlutonium Economy
Breeder reactors would greatly increase the availability of weapons-grade Plutonium.
Nuclear Power in the USNuclear Power in the US104 nuclear
plants Produce 20% US
ElectricityNo new plants
since 1973Why?
Nuclear AccidentsNuclear Accidents1979 Three Mile
Island partially core melt
1986 Chernobyl explosion and fire, release of radiation
Waste DisposalWaste DisposalWIPP near
Carlsbad, NM. Stores hi-level waste associated with nuclear weapons
Yucca Mountain, Nevada. High-level waste from commercial reactors.
Will there be a nuclear renewal?
Will there be a nuclear renewal?
Economics do not look good. Very capital intensive.
Fear of terrorismAnti-nuclear groups Waste disposal
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