Nuclear energy and radioactive waste disposal in geologic media

Factors in debate on use of nuclear power?

• reactor safety. What do Hallam, Nebraska and Chernobyl have in common?
• economics, alternatives, NIMBY and politics.
• waste disposal - where we will focus.

The science of radioactivity and associated health risks:

• what is an isotope?
• isotope sources: primordial, cosmogenic, artificial
• half lives and spontaneous decay.
• types of ionizing radiation:
  • alpha: limited penetration capacity, consists of 2 protrons and 2 neutrons
  • beta: energetic electrons given off when a neutron transforms to a protron.
  • gamma: most damaging, similar to x-rays.
• forced decay and nuclear power.
• measures of radiation exposure and roentgen and rems: measures of chemical disruption.
  • roentgen= 2.08 billion ion pairs in dry air.
  • rem = 1 roentgen absorption by human.
  • max. permissible dosage in U.S. .5 rem/year.
  • > 100 rem yields anemia.
  • >1000 radiation death.
  • longer term health effects, assoc. cancer can have a lag time of 30 years.
• background sources and magnitudes:
  • cosmic radiation at sea level vs. at Denver (28 vs. 50 mrem/year).
  • medical average (90 mrem/year), pre-1963 weapons fall out (4 mrem/year).
  • routine emission if U.S. was totally dependent on nuclear power (.23 mrem/year). Non-routine?
  • beware of averages.
  • Missing component of background?

High level radioactive waste disposal:

• the generators of and character of wastes and need for disposal.
  • round about 40,000 - 48,000 tons of high level waste presently.
  • defense department, nuclear power plants, medical facilities, research facilities.
• possible solutions?? You might think of advantages and disadvantages of each.
  • inject into space.
  • place into deep marine muds or subduction zones
  • ice sheet disposal.
  • stabilize into synthetic rock or ceramic.
  • terrestrial geologic burial.
• What factors would be desirable in a burial site selection?
• GIS as a way to handle these complex siting problems.
• Legislation and Yucca Mountain site:
  • National Waste Terminal Storage Act 1976.
  • Nuclear Waste Policy Act 1982.
  • Nuclear Waste Policy Amendments Act 1987.
  • DOE and NRC are main players.

Low level radioactive waste disposal

• Aiken S.C. and Hanford, WA were major repositories for this material.
• Low Level Radioactive Waste Policy Act of 1980
• 5 state compacts.
• by 1996 compacts and nonmember states must assume title to and liability for all low level waste generated within their borders.
• Boyd County site.
  • selected by Bechtel, Inc.
  • Pierre shale bedrock
  • shallow perched aquifers, wetlands.
  • enhanced above grade vaults.
  • Nebraska presently being sued for bad faith.

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