Nuclear Power - PowerPoint PPT Presentation

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Nuclear Power

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Nuclear Power Dennis Silverman, U C Irvine In the US, 20% of our electricity is produced by nuclear power. There are 103 US nuclear power plants. – PowerPoint PPT presentation

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Title: Nuclear Power


1
Nuclear Power
Dennis Silverman, U C Irvine
In the US, 20 of our electricity is produced by
nuclear power. There are 103 US nuclear power
plants.
2
California related reactors
Diablo Canyon, two reactors
San Onofre, two reactors
? of Palo Verde 1, 2, 3 in Arizona
3
California Nuclear energy
  • Each of the five reactors produces about 1,100
    million watts (megawatts) of electricity
  • This is enough to power one million homes per
    reactor
  • Each reactors production is equivalent to 15
    million barrels of oil or 3.5 million tons of
    coal a year.
  • The total 5,500 reactor produced megawatts is out
    of a peak state electrical power of 30,000
    40,000 megawatts.

4
Worldwide Nuclear Power Reactors
  • There are 440 nuclear power reactors in 31
    countries.
  • 30 more are under construction.
  • They account for 16 of the worlds electricity.
  • They produce a total of 351 gigawatts (billion
    watts) of electricity.

5
World Nuclear Power Plants
6
Nuclear Electricity Production by Countries and
Regions in Gigawatts (World Total 350 Gigawatts)
and percent of electricity
7
How a Nuclear Reactor works
  • 235U fissions by absorbing a neutron and
    producing 2 to 3 neutrons, which initiate on
    average one more fission to make a controlled
    chain reaction
  • Normal water is used as a moderator to slow the
    neutrons since slow neutrons take longer to pass
    by a U nucleus and have more time to be absorbed
  • The protons in the hydrogen in the water have the
    same mass as the neutron and stop them by a
    billiard ball effect
  • The extra neutrons are taken up by protons to
    form deuterons
  • 235U is enriched from its 0.7 in nature to about
    3 to produce the reaction, and is contained in
    rods in the water
  • Boron control rods are inserted to absorb
    neutrons when it is time to shut down the reactor
  • The hot water is boiled or sent through a heat
    exchanger to produce steam. The steam then
    powers turbines.

8
Nucleons more tightly bound in Fission Product
Nuclei Gives 200 Mev Energy per Fission
9
Nuclear Fission from Slow Neutrons and Water
Moderator
10
Inside a Nuclear Reactor
  • Steam outlet ?
  • Fuel Rods ?
  • Control Rods ?

11
Energy Taken out by Steam Turbine
12
Production of Plutonium (Pu) in Nuclear Reactors
  • 239Pu is produced in nuclear reactors by the
    absorption of a neutron on 238U, followed by two
    beta decays
  • 239Pu also fissions by absorbing a thermal
    neutron, and on average produces 1/3 of the
    energy in a fuel cycle.
  • 239Pu is relatively stable, with a half life of
    24 thousand years.
  • It is used in nuclear weapons
  • It can be bred for nuclear reactors

13
Nuclear Weapons to Reactor Fuel
  • We are buying highly enriched uranium (20 235U)
    from the former Soviet Unions nuclear weapons
    for 20 years from 1993--2013
  • Converting it to low enriched uranium (3 235U)
    for reactor fuel
  • It will satisfy 9 years of US reactor fuel demand
  • It comes from 6,855 Soviet nuclear warheads so far

14
Nuclear Plant Future
  • The countries of the world are each planning
    their own course of nuclear plant development or
    decline
  • Nuclear power is competitive with natural gas
  • It is non-polluting
  • It does not contribute to global warming
  • Obtaining the fuel only takes 5 of the energy
    output
  • Plant licenses have been extended from 20 years
    to an additional 20 years

15
Nuclear Plant Future
  • Newer designs are being sought to make them more
    economical and safer
  • Preapproval of a few designs will hasten
    development
  • Disposal of high level radioactive waste still
    being studied, but scientists believe deep burial
    would work
  • Because they are have large electrical output,
    their cost at 2 billion is hard to obtain and
    guarantee with banks
  • Replacing plants may be cheaper using the same
    sites and containment vessels

16
Nuclear Problems and Solutions
  • Three Mile Island 1979
  • 50 core meltdown, stuck valve with no indicator
    released water, but containment vessel held
  • More sensors added, better communication to
    experts in Washington, dont turn off emergency
    cooling
  • 28 year US safety record since accident
  • Chernobyl 1986
  • Human stupidity turned off cooling system
  • Poor steam cooling reactor design allowed
    unstable steam pocket to explode
  • Graphite caught fire
  • Design not used in other countries

17
Yucca Mountain Project Nuclear Fuel and High
Level Waste Repository
  • Much more secure repository than leaving high
    level waste at 60 reactor sites around the
    country.
  • On old atomic bomb testing base, inside a
    mountain.
  • The storage is above the water table.
  • The Yucca Mountain site would be 60 filled by
    present waste.
  • US has legal commitment to the reactor industry.
  • Site has been studied extensively by scientists
    for over 20 years.
  • Will store waste during its 10,000 year decay
    time.
  • Questions of how to deflect dripping water around
    and under the storage vessels.
  • Questions of radioactive decay weakening storage
    containers.
  • A solution would be to build containers that can
    be opened and reincased, or to which surrounded
    casings could be added.

18
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19
Liquid Metal Fast Breeder Reactor
  • Uses the fast neutrons from 235U fission on
    surrounding 238U to produce 239Pu
  • In 10-20 years, enough Pu is produced to power
    another reactor
  • No moderators are allowed
  • No water, must use liquid sodium coolant
  • U must be at 15-30 enrichment to generate power
    with fast neutrons while breeding Pu
  • This is at weapons grade enrichment, however
  • Super-Phenix in France has operated for 20 years

20
Nuclear Power Proposed Solution?
  • Richard Garwin , MIT and industry propose
  • If 50 years from now the world uses twice as much
    energy, and half comes from nuclear power
  • Need 4,000 nuclear reactors, using about a
    million tons of Uranium a year
  • With higher cost terrestrial ore, would last for
    300 years
  • Breeder reactors creating Plutonium could extend
    the supply to 200,000 years
  • Nonpolluting, non-CO2 producing source
  • Need more trained nuclear engineers and sites
  • Study fuel reprocessing, waste disposal, and
    safer designs.
  • While nuclear reactors have to be on all day and
    night, and power use is less at night, they could
    be used to charge up electric cars.
  • Until electric cars or a hydrogen generation
    economy, they might only be used for the 40 of
    generation used at night, up from the present 20
    that they generate.

21
Fusion Reactors
  • Fusion easiest for Deuteron (D) Tritium(T)
  • D(p,n) T(p,nn) ? 4He(pp,nn) n
  • in a high temperature plasma.
  • Replacement T created from Li blanket around
    reactor
  • n 6Li ? 4He T
  • Fusion reactors
  • International ITER in 2012 for research for a
    decade, costing 5 billion
  • Current stalemate over siting in France or Japan
  • Followed by DEMO for a functioning plant, taking
    another 10 years.
  • Design and completion of a commercial plant not
    until 2050.
  • US Lithium supply would last a few hundred years.
  • Still would be a radioactive waste disposal
    problem.

22
International Thermonuclear Experimental Reactor
(ITER)
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