Nuclear%20Fusion%20Energy

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Nuclear FusionEnergy

• Rishi Gohil
• ChE 379 Energy Technology and Policy
• Dr. Thomas Edgar
• Fall 2007

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Nuclear Fusion Principle

• Energy generated by joining two elements with low
  atomic numbers.
• Most efficient reaction known is fusion of
  Hydrogen isotopes, Deuterium and Tritium, to form
  Helium.
• Fusion is source of energy for stars and the Sun.
• High temperatures gt 100 million degrees Kelvin
  needed for fusion on earth
• At high temperature, the gas mixture forms a
  plasma (hot, electrically charged gas)

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Nuclear Fusion

• This reaction releases 17.6 MeV of energy. No
  limit on amount of fusion that can occur (unlike
  fission).

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Requirements for Fusion Reaction

• Plasma Temperature100-200 million Kelvin
• Needed to overcome natural positive repulsive
  forces of plasma ions
• Energy Confinement Time 4-6 seconds
• The Energy Confinement Time is a measure of how
  long the energy in the plasma is retained before
  being lost.
• Central Density in Plasma1-2 x 1020 particles
  m-3
• Large density needed because number of fusion
  reactions per unit volume is roughly proportional
  to the square of the density

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Plasma Toroid (Tokamak)
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Flow of Energy
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Challenges

• Current research in controlling high temperature
  plasma
• How to heat plasma to gt100 million deg C.
• How to confine such a plasma
• How to sustain the reactions.

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Advantages

• Abundant fuels Deuterium (from water), Tritium
  (from Lithium) and Lithium (plentiful on Earths
  crust).
• Inherently safe Because conditions for reaction
  are stringent and small amounts of fuel used
• Environmentally safe No greenhouse gas emissions
  and byproduct of reaction is Helium.

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JET (Joint European Torus)

• JET Worlds largest nuclear fusion research
  facility

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Fusion Reactor

• EU to build pilot fusion reactor, Iter.
• Cost 4.57 Billion EURO (2000 prices) over 10 yrs
• Life 35 years
• Countries Involved 7
• Design reactions occur in 100 million degree gas
  (plasma) suspended in donut shaped magnetic
  field.
• Problems Sustained and stable reactions
• Potential 500 MW output from 70 MW power input
  during pulses of at least 400 secs.
• If technology works commercial reactor, Demo,
  will be built.
• Advantages No greenhouse emissions, inherently
  safe due to malfunction shutdown systems, no
  high-level long-lived radioactive waste produced.

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Iter Timeline
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References

• "Nuclear Fusion 'Put to the Test'" BBC NEWS 17
  Feb. 2005. 19 Nov. 2007 lthttp//news.bbc.co.uk/2/l
  ow/science/nature/4270297.stmgt.
• Fusion Power." United Kingdom Atomic Energy
  Authority. 20 Nov. 2007. lthttp//www.fusion.org.uk
  /gt.
• "JET." EFDA. 20 Nov. 2007. lthttp//www.jet.efda.or
  g/index.htmlgt.  
• Nuclear Fusion howstuffworks.19 Nov 2007.
  Craig Freudenrich, Ph.D. lthttp//science.howstuffw
  orks.com/fusion-reactor3.htmgt