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