Nuclear fuel rods in the United States typically spend three years in a commercial power plant's nuclear reactor and a few more years in a storage pool at the plant, glowing a stunning, ominous blue from its now highly radioactive state. It's then encased in concrete casks, still on site. These casks await shipment to, as of 2009, an undetermined permanent storage site where the spent fuel will remain lethal for at least 250,000 years, according to a January 2009 story in Scientific American.
There are alternatives for spent nuclear fuel. Reprocessing the fuel to be used again in reactors would greatly reduce the amount of waste needed to be stored. But reprocessing has its own costs, and its own dangers.
Fuel Rod Composition
Fuel rods are composed of enriched uranium, where the level of the U-235 isotope is raised from the natural level of .7 percent of the total uranium present to about 3.5 percent, the level needed to start and maintain a nuclear chain reaction. The reactor core of a power plant, according to the World Nuclear Association, is made up of several hundred fuel assemblies, pellets of uranium encased in a metal cladding. When a spent nuclear rod is removed from the reactor, it is highly radioactive and gives off a great deal of heat. But it still contains about 96 percent of its original uranium, though the fissionable U-235 has been reduced to only one percent. Another one percent of the spent rod is plutonium, produced while the fuel was in the reactor.
A story from ClimateWire, published in the New York Times in May 2009, reported that more than 90 percent of the energy in spent nuclear fuel remains available for reprocessing. Yet development of nuclear fuel reprocessing was stopped in the 1970s during President Carter's administration, and though the ban was lifted by President Reagan, those efforts didn't resume, despite renewed interest in recycling the fuel.
Europe, Japan and Russian regularly reprocess fuel with a capacity of handling 5,000 tons per year. France has been reprocessing fuel at a facility in La Hague since 1966. Reprocessing separates uranium and plutonium from the waste products of the fuel rods. The recovered uranium can subsequently be re-enriched and used again as fuel for a nuclear plant.
Recycling plutonium as fuel
Plutonium, though a byproduct of fission in a nuclear plant, is normally not introduced as fuel into commercial reactors. To recycle plutonium for this purpose, it can be blended with enriched uranium to produce a mixed oxide (MOX) fuel in a fuel fabrication plant. The World Nuclear Association reports that MOX fuel fabrication occurs at plants in Belgium, France, German, Britain, Russia and Japan, with more under construction. The association stated about 30 reactors in Europe are licensed to load 20 to 50 percent of their fuel cores with MOX fuel, and Japan plans to have one third of its 54 reactions using MOX by 2010.
Or use the plutonium for bombs
The plutonium recovered from nuclear fuel reprocessing is not weapons grade without further processing, but the danger of nuclear proliferation raises concerns and opposition.
"One of the biggest obstacles to increasing security is the proliferation of reprocessing plants, which produced separated plutonium that can be used in weapons," Edwin Lyman, a senior staff scientist at the Union of Concerned Scientists, told the Scientific American. The group said 250 metric tons of plutonium, enough for 30,000 nuclear weapons, has already been recovered through reprocessing.
Just bury the stuff
Nuclear reactors in the United States produce around 2,000 metric tons of radioactive waste per year, according to the Department of Energy. U.S. policy since the 1970s is for the federal government to take the spent nuclear waste and bury them deep at a nuclear dump ground. In 1987, Congress designated Nevada's Yucca Mountain as the site to hold the nuclear waste, but it has yet to open. In 2009, President Obama proposed to stop federal funding for Yucca while a new commission reviews the policies.
Reprocessing would reduce the volume of U.S. nuclear waste, perhaps by a factor of four or five according to a study by Areva, France's majority state-owned complex of nuclear companies. Once recycled, fuel components have a higher concentration of radioactive materials, but the study, done for the Yucca Mountain repository, finds the radiation would not be as long-lived.
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