There are various types of wastes created in the production of nuclear power. The two main categories are fission products and transuranic elements. Fission products, the more radioactive (the tendency of an element to break down spontaneously into one or more elements) of the two, are formed by fission, the splitting of atoms of uranium, cesium, strontium, or krypton. Transuranic elements, which remain radioactive far longer than fission products (hundreds of thousands of years), form when uranium atoms absorb free neutrons.
These wastes exist in three forms: 12 feet- (4 meter-) long spent fuel rods; high-level radioactive waste in liquid or sludge; and low-level radioactive waste in such things as reactor hardware, piping, toxic resins, or water from the fuel pool.
The U.S. government agency charged with the storage and disposal of nuclear waste is called the Office of Civilian Radioactive Waste Management, a division of the Department of Energy. This agency is involved in both the short-term storage of nuclear wastes and the development of a long-term storage site. At present, all nuclear waste is placed in short-term storage.
It has been proposed that a permanent, high-level nuclear waste repository be constructed at Yucca Mountain, located at the edge of the Nevada Test Site in southeastern Nevada. The Nevada Test Site is one of two locations where most the U.S. nuclear weapons testing took place. Despite opposition from Nevada residents, the repository—which has not yet under construction—is slated for completion early in the twenty-first century. The Nuclear Waste Policy Act of 1982, however, mandated that a method of permanent disposal of nuclear waste be established by 1998.
In the United States, most of the spent nuclear fuel rods have been sitting for ten years or more in water-filled pools at the individual plant sites. Most low-level radioactive waste has been stored in steel drums in shallow landfills at six nuclear dump sites and at the Hanford Nuclear Reservation in the state of Washington. Most high-level nuclear waste has been stored in double-walled stainless-steel tanks surrounded by 3 feet (1 meter) of concrete.
The best-known storage method, developed by the French in 1978, is to incorporate the waste into a special molten glass mixture, then enclose it in a steel container. All countries that operate nuclear power plants agree that the treated nuclear waste should then be buried in rock layers, far underground. After the waste is inserted in the ground, the pits would be filled and sealed.
An estimated 8,000 to 9,000 metric tons (8,816 to 9,918 tons) of high-level nuclear waste, from both nuclear power and nuclear weapon production, is created in the United States each year. The safe disposal of nuclear wastes is one of the greatest challenges to nuclear power and nuclear weapons producers. And as nuclear waste continues to pile up, the potential consequences to the environment and human health also continue to grow.
Sources: Cunningham, William P., et al. Environmental Encyclopedia, pp. 558, 583-84; "Energy Conversion: Waste Disposal." Encyclopaedia Britannica CD 97; EPA Fact Sheet: Setting Environmental Standards for Yucca Mountain, [Online] Available http://www.eap.gov/radiation/yucca/factrev.htm., April 1, 1996; How in the World?: A Fascinating Journey Through the World of Human Ingenuity, pp. 122-23; Naar, Jon. Design for a Livable Planet, pp. 161-63.