Key Issues
Nuclear Fuel Production: A Four-Step Process
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From Ore to Pellets: A Multi-Step Process
A nuclear power plant, like most other types of power plants, generates electricity by boiling water into steam that drives a turbine generator. Splitting uranium atoms—the fission process—creates heat to boil the water.
Before its use in a reactor, uranium must undergo four processing steps to convert it from an ore to solid ceramic fuel pellets: mining and milling, conversion, enrichment, and fabrication. The resulting pellets are loaded into fuel rods. When grouped, the rods form bundles, or “fuel assemblies,” for insertion into the reactor.
Mining and Milling: From Ore to ‘Yellowcake’
Uranium miners employ several techniques: surface or “open pit” mining, underground mining, and in-situ leach mining, which involves using liquids to recover minerals from underground ore. Uranium also can be a byproduct of other mineral processing operations.
Ore mined from open-pit and underground mines travels to a conventional mill, where it is crushed, ground and leached to dissolve the uranium. Solvents or ion exchange processing removes the uranium. The resulting uranium oxide, or “yellowcake,” is filtered, dried and packaged.
In-situ leach mining involves the injection of carbonated water through specially drilled wells into an ore body several hundred feet underground. The injected solutions penetrate the ore deposits and dissolve the uranium. This process brings the uranium-bearing solution to the surface, where the uranium is extracted and the leach solutions are again injected into the ore body.
Most U.S. uranium reserves are found in Arizona, Colorado, New Mexico, Texas, Utah and Wyoming. Primary U.S. uranium production in 2007 came from one U.S. mill and five in-situ leach plants.
Total U.S. uranium production from all sources in 2007 was 4.5 million pounds of uranium oxide, slightly higher than in 2006. Worldwide production in 2007 was about 108 million pounds. That same year, U.S. utilities purchased 33 percent of their uranium from Russia, 23 percent from Australia, 21 percent from Canada, 8 percent from the United States, 6 percent from Namibia, and the remaining 9 percent from several other countries.
Conversion: Yellowcake to Uranium Hexafluoride
The uranium oxide, or yellowcake, requires further processing before its use as a fuel. In the next step, the uranium oxide goes to a conversion plant, which removes impurities and chemically converts the material to uranium hexafluoride. The compound is heated to become a gas then loaded into cylinders, where it cools and condenses into a solid.
One of the world’s five commercial conversion plants is in the United States. The others are in Canada, France, Russia and the United Kingdom.
ConverDyn, a general partnership between affiliates of General Atomics and Honeywell International Inc., is the exclusive agent for conversion sales from Honeywell’s conversion plant in Metropolis , Ill. The facility has a production capacity of approximately 15,000 metric tons (MTU) per year of uranium hexafluoride. The company is evaluating options to increase capacity consistent with market needs. U.S. annual demand for conversion is approximately 20,000 MTU per year.
Annual world requirements for conversion as of 2007 are approximately 60,000 MTU. The world’s conversion plants currently have a total maximum capacity of about 66,000 MTU. In 2007, roughly 40,000 MTU were produced. Although inventory drawdowns—in addition to recycling—supplied the remainder of 2007 world uranium requirements, those inventories are expected to provide smaller portions of requirements in the future.
From Ore to Pellets: A Multi-Step Process
A nuclear power plant, like most other types of power plants, generates electricity by boiling water into steam that drives a turbine generator. Splitting uranium atoms—the fission process—creates heat to boil the water.
Before its use in a reactor, uranium must undergo four processing steps to convert it from an ore to solid ceramic fuel pellets: mining and milling, conversion, enrichment, and fabrication. The resulting pellets are loaded into fuel rods. When grouped, the rods form bundles, or “fuel assemblies,” for insertion into the reactor.
Mining and Milling: From Ore to ‘Yellowcake’
Uranium miners employ several techniques: surface or “open pit” mining, underground mining, and in-situ leach mining, which involves using liquids to recover minerals from underground ore. Uranium also can be a byproduct of other mineral processing operations.
Ore mined from open-pit and underground mines travels to a conventional mill, where it is crushed, ground and leached to dissolve the uranium. Solvents or ion exchange processing removes the uranium. The resulting uranium oxide, or “yellowcake,” is filtered, dried and packaged.
In-situ leach mining involves the injection of carbonated water through specially drilled wells into an ore body several hundred feet underground. The injected solutions penetrate the ore deposits and dissolve the uranium. This process brings the uranium-bearing solution to the surface, where the uranium is extracted and the leach solutions are again injected into the ore body.
Most U.S. uranium reserves are found in Arizona, Colorado, New Mexico, Texas, Utah and Wyoming. Primary U.S. uranium production in 2007 came from one U.S. mill and five in-situ leach plants.
Total U.S. uranium production from all sources in 2007 was 4.5 million pounds of uranium oxide, slightly higher than in 2006. Worldwide production in 2007 was about 108 million pounds. That same year, U.S. utilities purchased 33 percent of their uranium from Russia, 23 percent from Australia, 21 percent from Canada, 8 percent from the United States, 6 percent from Namibia, and the remaining 9 percent from several other countries.
Conversion: Yellowcake to Uranium Hexafluoride
The uranium oxide, or yellowcake, requires further processing before its use as a fuel. In the next step, the uranium oxide goes to a conversion plant, which removes impurities and chemically converts the material to uranium hexafluoride. The compound is heated to become a gas then loaded into cylinders, where it cools and condenses into a solid.
One of the world’s five commercial conversion plants is in the United States. The others are in Canada, France, Russia and the United Kingdom.
ConverDyn, a general partnership between affiliates of General Atomics and Honeywell International Inc., is the exclusive agent for conversion sales from Honeywell’s conversion plant in Metropolis , Ill. The facility has a production capacity of approximately 15,000 metric tons (MTU) per year of uranium hexafluoride. The company is evaluating options to increase capacity consistent with market needs. U.S. annual demand for conversion is approximately 20,000 MTU per year.
Annual world requirements for conversion as of 2007 are approximately 60,000 MTU. The world’s conversion plants currently have a total maximum capacity of about 66,000 MTU. In 2007, roughly 40,000 MTU were produced. Although inventory drawdowns—in addition to recycling—supplied the remainder of 2007 world uranium requirements, those inventories are expected to provide smaller portions of requirements in the future.
