Fact Sheet  
Office of Civilian Radioactive Waste Management
 
Graphic: alternative drawings with text "Scientists looked at many alternatives"

Managing nuclear waste: Options considered

"Scientists studied a broad range of options for managing spent nuclear fuel and high-level radioactive waste"
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.

A variety of options were considered

Scientists studied a broad range of options for managing spent nuclear fuel and high-level radioactive waste. The options included:
  1. Leaving it where it is
  2. Disposing of it in various ways
    • Sub-seabed disposal
    • Very deep-hole disposal
    • Space disposal
    • Ice-sheet disposal
    • Island geologic disposal
    • Deep-well injection disposal
  3. 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

Leaving it where it is

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.

Sub-seabed disposal

sub-seabed disposalScientists 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.

Very deep-hole disposal

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 holes.

Space disposal

space disposalThe 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 unacceptable option.

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.

Ice-sheet disposal

ice-sheet disposalScientists 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 processes.

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 melting.

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.

Island geologic disposal

island geologic disposalScientists 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 volcanic activity.

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 consideration.

Deep-well injection disposal

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 the environment.

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.

Reprocessing

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.
 

Yucca Mountain Project