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Nuclear Power

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Title: Nuclear Power


1
Nuclear Power
2
How does it work?
  • Uranium-235 is often use to fuel nuclear power
    plants. It has an interesting property that makes
    it useful for this because it can undergo induced
    fission.

3
Nuclear Fission
4
Chain Reaction
  • When the neutrons ejected from each fission hit
    another nearby nucleus, that one splits and
    releases more neutrons, etc. This sets up a
    chain reaction that keeps going and going
    until..

5
Control Rods are put into action
  • These are made of a material that absorbs
    neutrons and are lowered when the reaction needs
    to be slowed down or stopped.

6
How is the electricity created?
  • The uranium bundle generates the heat which turns
    the water into steam. This drives the turbine,
    which spins a generator to produce power.

7
Outside the Power Plant
  • Once you get past the reactor itself, there is
    little difference between a nuclear power plant
    and a coal or oil powered one.

8
The containment vessel
  • Nuclear reactors are typically housed inside a
    concrete liner that acts as a radiation shield.
    That liner is housed inside a much larger steel
    containment vessel.

9
Advantages of Nuclear Power
  • Minimal air pollution
  • Water pollution is low (some thermal pollution
    exists)
  • Disruption of land is low to moderate
  • (except the mining of uranium)
  • One pound of U-235 can produce as much heat
    energy as 1,500 tons of coal!

10
Disadvantages of Nuclear Power
  • Highly toxic nuclear waste produced (some take
    thousands to millions of years to decay)
  • Lifespan of facilities only 15-40 years
  • Low net energy yield lots of energy required
    for mining uranium, processing ore or dismantling
    the plant
  • Safety and malfunction issues

11
So where does the plutonium come from anyway?
  • Power plants create it when the uranium in their
    fuel fissions. Some of it ends up in the spent
    fuel as waste.
  • Different isotopes of plutonium have different
    half-lives and different uses

12
What is a breeder reactor?
  • The Breeder Reactor was developed to use
    uranium-238. Here's how it works. A reactor is
    built with a core of fissionable plutonium,
    Pu-239. The plutonium-239 core is surrounded by a
    layer of uranium-238. As the plutonium-239
    undergoes spontaneous fission, it releases
    neutrons. These neutrons convert uranium-238 to
    plutonium-239. In other words, this reactor
    breeds fuel (Pu-239) as it operates. After all
    the uranium-238 has been changed to
    plutonium-239, the reactor is refueled.
  • Plutonium production reactors operated by the
    U.S. government during the Cold War have all shut
    down.

13
Nuclear Power Plants in the United States
14
Who relies most on nuclear energy?
15
Nuclear Catastrophes
16
The INES scale
  • The International and Radiological Event Scale is
    a worldwide tool for communicating to the public
    in a consistent way the safety significance of
    nuclear and radiological events.

17
(No Transcript)
18
Three Mile Island March 1979 Pennsylvania
INES Level 5
19
What happened?
  • A cooling malfunction caused a partial meltdown.
    Some radioactive water was released as well as
    radioactive gas. Many people were evacuated. The
    reactor did not explode as feared. No one was
    killed.
  • A 25 year follow-up study in 2004 of 35,000
    residents within a 5 mile radius of TMI showed no
    significant increase in deaths from cancer.

20
The China Syndrome
  • This movie, released in March of 1979 depicted a
    very similar fictional incident to that which
    occurred on Three Mile Island about a week after
    it was released in theaters!!

21
ChernobylApril 1986Ukraine
INES Level 7
22
What happened?
  • They were running a safety check. Regulations
    called for a minimum of 30 control rods. Only 6-8
    were used. This led to a series of events that
    caused rapid overheating and deformed the core.
    The extra control rods could not be inserted and
    the core melted, causing an explosion. Fires
    lasted for nine days.

23
They made some BIG mistakes
  • The emergency cooling system was turned off
  • Past-due safety check was being run by
    inexperienced night crew
  • Automatic safety devices that shut down the
    reactor were shut off
  • Power output was lowered too much
  • The plant had no secondary containment shell

24
The effects
  • It caused 30 immediate fatalities to workers and
    exposed approx. 500,000 people to dangerous
    levels of radiation.
  • Air currents carried radioactive particles high
    into the atmosphere and allowed spreading.

25
The result?
  • These serious accidents put a definite halt on
    most plans to build new power plants in the
    United States and caused some that were already
    built to be shut down indefinitely. One such
    plant here on Long Island is..

26
Shoreham Power Plant
Officially decommissioned in 1989
Customers are still paying for the 6 billion
dollar debt it has left.(3 surcharge on their
electric bills for 30 years)
27
Fukushima Daiichi DisasterJapan March 11, 2011
Original INES Level 5/Upgraded to Level 7 in April
28
A powerful tsunami generated by a magnitude 9.0
quake at sea slams into the power plant
  • Damage is done to four of six reactors
  • Cooling systems fail
  • Fires are set off
  • Hydrogen gas causes explosions
  • Engineers use seawater in effort to cool down
    cores

29
The Outcome?
  • The world becomes skeptical again about the use
    of nuclear energy as old fears are revived .
  • A handful of workers at the plant were
    accidentally killed while trying to control the
    overheating reactors.
  • It is estimated that 1,000 people will die from
    cancers which result from radiation exposure.

30
Electricity Production
  • The World
  • The United States
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