Starting in the 1950s, U.S. scientists began to research ways to manage
highly radioactive materials accumulating at power plants and other
sites nationwide. Long-term surface storage of these materials poses
significant potential health, safety, and environmental risks.
Scientists studied a broad range of options for managing spent nuclear
fuel and high-level radioactive waste. The options included:
- Leaving it where it is
- Disposing of it in various ways
Making it safer through advanced technologies
International scientific consensus holds that these materials should
eventually be disposed of deep underground in what is called a geologic
repository. In a recent special report, the National Academy of Sciences
summarized the various studies and emphasized that geologic disposal
is ultimately necessary.1
- Sub-seabed disposal
- Very deep-hole disposal
- Space disposal
- Ice-sheet disposal
- Island geologic disposal
- Deep-well injection disposal
Currently, America’s spent nuclear fuel and high-level radioactive
waste are temporarily stored above ground at 131 locations in 39 states.
There are many disadvantages associated with long-term surface storage,
even if only for another 100 years.
If left where they are indefinitely, the materials could become a
serious hazard to nearby populations and the environment. This could
be an even greater concern if global climate change causes the oceans
to rise, as many scientists believe is happening.
Most of the storage sites are near population centers, and because
nuclear reactors require abundant water, these sites are also located
near rivers, lakes, and seacoasts.
If not continuously maintained and safeguarded, this stored material
could deteriorate and travel through groundwater and surface water
runoff to rivers and streams that people use for domestic and agricultural
purposes. Should this occur, 20 major waterways and all U.S. seacoasts
could be adversely impacted.
considered burying radioactive waste under the ocean floor, but there
are problems associated with this option.
Whether waste buried under the seabed could be recovered, if necessary,
is questionable. Developing an effective international, legal, and
administrative structure to develop, regulate, and monitor a sub-seabed
repository would be challenging as well.
Beyond technical and political considerations, the United States signed
the London Convention in October 1993. This international agreement,
which remains in force until 2018, bans disposing of radioactive materials
at sea. After that time, the sub-seabed disposal option can be revisited
at 25-year intervals.
Another option scientists investigated was disposal in very deep holes:
placing high-level radioactive waste containers as deep as about six
miles (10,000 meters) underground. At such depths, the radioactivity
theoretically could be isolated until it decayed to a safe level.
Very deep-hole disposal was rejected as an option, however. While
it would keep radioactive waste below most groundwater, the surrounding
rock would have to retain its structure under extreme heat and radiation.
Scientists do not know enough about how radioactive waste would behave
under the exceptionally high pressures and temperatures of very deep
National Aeronautics and Space Administration (NASA) and the DOE also
researched several methods of disposal in space. Possibilities included
launching waste containers into the sun or putting them on the moon.
Space disposal offers the attraction of permanent separation of waste
from the human environment.
However, the disadvantages of space disposal are great.
The possibility of an accident during launch and the potential for
radioactive waste to be scattered by such an accident make this an
In addition, space disposal is impractical because of the number of
launches that would be required.
Establishing international agreements on how such a program would
be operated and regulated would also be difficult.
also considered burying radioactive waste in polar ice.
Advantages to this option include the lack of population in polar
regions and the stability and thickness (several miles, thousands
of meters) of polar ice.
One drawback to this option is the uncertain disposal and/or retrieval
Another is the potential effect of future climate changes on the stability
and size of polar ice masses. Radioactive wastes could be released
into the environment if global climate changes increased polar ice
This option also would be extremely expensive due to the remote location
and adverse weather.
Finally, the Antarctic Treaty of 1959 prohibits disposing of radioactive
waste on the Antarctic continent.
looked at burying radioactive waste beneath remote islands that lacked
valuable resources and were far from large continental landmasses.
One drawback to island geologic disposal concerned the risks associated
with ocean transport, especially during bad weather.
Also, many islands experience frequent and intense earthquake and
In addition, some islands have geologic structures that allow seawater,
as well as fresh water, to penetrate underlying rock. The presence
of water could contribute to waste container corrosion, releasing
and eventually transporting radioactive particles into the environment.
The potential for opposition from nearby countries was an additional
Scientists studied a disposal option called deep-well injection, which
involves pumping pressurized liquid high-level radioactive waste to
depths of about 3,500 to 16,000 feet (1,000 to 5,000 meters).
The waste theoretically would move throughout a porous rock formation
protected by a layer of solid (impermeable) rock. Sandstone overlaid
by shale is considered a good choice for deep-well injection because
of shale’s ability to isolate the waste from groundwater and
One disadvantage to this option was the need for either mechanical
or chemical processing of the spent nuclear fuel prior to injection.
Another concern was the potential movement of liquid waste outside
the porous rock formation. This could increase the chances that the
irretrievable waste might escape into the environment.
Some nations reprocess their spent nuclear fuel. Reprocessing requires
a complex set of mechanical and chemical treatments to separate out
the uranium from the plutonium, which is produced by the atom-splitting
in the reactor. The material can then be reconstituted as fresh fuel
pellets to produce more electricity.
1 Board on Radioactive Waste Management, National Research
Council, National Academy of Sciences, Disposition of High-Level Waste
and Spent Nuclear Fuel: The Continuing Societal and Technical Challenges.
National Academy Press: Washington, D.C. 2001.