Extraction and Enrichment of Uranium

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Extraction and Enrichment of Uranium

• Author Aaron L. Balsmeier
• October 22, 2002

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Uranium and Aerospace
Why do you care about uranium as an aerospace
engineer?

• Nuclear Powered Aerospace Vehicles
• Nuclear Satellites
• Nuclear Rockets
• Aerospace Based Weapons Systems
• Nuclear Weapons Carried by Rockets
• Depleted Uranium Ammunition

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Nuclear Powered Satellites

• Many deep space satellites use nuclear power. A
  process called radioisotope thermoelectric
  generation (RTG) is utilized. This process uses
  plutonium which is only produced by nuclear
  reactors. All of which run off of enriched
  uranium or a fuel that was produced in a reactor
  that does. Some satellites that use nuclear
  power are
• Pioneer
• Viking
• Voyager
• Cassini
• Galileo

For more information on RTGs visit
http//me.eng.sunysb.edu/mec290/rtgs/ For more
information on the production of plutonium
visit http//www.fas.org/nuke/intro/nuke/plutoniu
m.htm
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Pioneer
Viking
Cassini
Voyager
Galileo
Pictures Courtesy of http//me.eng.sunysb.edu/mec
290/rtgs/
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Nuclear Weapons
Enriched uranium is used in nuclear weapons
carried by advanced rocket systems.
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Extraction of Uranium
Courtesy of http//chemcases.com/nuclear/nc-06.ht
m
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Enriched Uranium
Natural Abundance of Uranium Isotopes
Enriched uranium contains more than 1 U-235.
Normally the quantity of U-235 is increased to
around 5 for use in nuclear fuels (reactors,
rocket fuel elements). The uranium in nuclear
weapons is enriched to much greater levels, which
is called highly enriched uranium if the
concentration of U-235 is above 20.
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Techniques

• Several common techniques for isotope separation
  are
• Electromagnetic isotope separation
• Gaseous diffusion
• Gas centrifuge

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Electromagnetic Separation
The method of electromagnetic isotope separation
relies on the use of ions and a magnetic field.
As ions are accelerated and the passed through a
magnetic field their path will be deflected.
Isotopes that have different mass will be
deflected by differing amounts. This allows for
the different isotopes to be collected by
determining the path they will have due to their
charge and a known magnetic field and placing
collectors at those locations.
Figure from Avery, D. G., and Davies, E.,
Uranium Enrichment by Gas Centrifuge, Mills
Boon Limited, London, 1973.
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Gaseous Diffusion
Enrichment by gaseous diffusion relies on the
property of isotopes of different masses to
diffuse through a porous membrane at different
rates. The gaseous uranium hexaflouride is
generally pressurized and forced through a porous
membrane. The smaller isotopes have a greater
tendency to diffuse through the membrane at a
greater rate than the larger ones. This means
that the concentration of U-235 will be higher on
the low-pressure side of the membrane.
Figure Courtesy of http//www.nrc.gov/materials/f
uel-cycle-fac/ur-enrichment.html
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Gas Centrifuge
The gas centrifuge operates on the principle of
diffusion caused by a pressure gradient. The
gaseous UF6 is passed through the centrifuge
while it is spinning. The centrifugal force
causes the heavier (U-238) isotopes to migrate to
the outside of the centrifuge. The enriched
portion will follow the path described by a1.
The depleted portion of the gas will follow the
path shown by a2.
Figure from Avery, D. G., and Davies, E.,
Uranium Enrichment by Gas Centrifuge, Mills
Boon Limited, London, 1973.
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Sources for More Information
Balsmeier, Aaron, L. Extraction and Enrichment
of Uranium University of Kansas, Department of
Aerospace Engineering, University of Kansas,
2002 http//www.fas.org/nuke/intro/nuke/uranium.ht
m http//www.uic.com.au/uicchem.htm
http//www.rossing.com/uranium_production.htm
http//www.wma-minelife.com/uranium/uranium.html
http//chemcases.com/nuclear/nc-06.htm
http//www.energyres.com.au/ranger/mill_diagram.p
df http//www.usec.com/v2001_02/HTML/Facilities_P
aducahOverview.asp http//www.uic.com.au/nip33.ht
m http//www.uic.com.au/index.htm
http//www.silex.com.au/ http//www.nrc.gov/mate
rials/fuel-cycle-fac/ur-milling/ur-milling-fac.htm
l http//www.nrc.gov/materials/fuel-cycle-fac/ur-
enrichment.html http//me.eng.sunysb.edu/mec290/r
tgs/ http//www.fas.org/nuke/intro/nuke/plutonium.
htm