1985: DOE briefly tests, then abandons $1.5 billion in centrifuge work in favor of the more promising Atomic Vapor Laser Isotope Separation process, or AVLIS. Uranium enrichment operations cease at Oak Ridge, Tenn.
1992: Congress creates government-owned U.S. Enrichment Corp.
1998: Government sells USEC for $1.9 billion in a public stock offering.
1999: USEC abandons $100 million in AVLIS research as not cost-efficient. Research turns to gas centrifuge.
2001: USEC closes Piketon enrichment plant and merges work with Paducah, the only plant of its type left running in the nation.
2002: USEC says a test gas centrifuge plant will be built in Piketon by 2004.
2003:USEC competitor Louisiana Energy Services seeks regulatory approval for a $1.2 billion gas centrifuge plant in New Mexico and signs contracts with several nuclear utilities to buy half the plantís first 10 years of production. LES includes Urenco, a European firm using gas centrifuge for decades, and Exelon, USECís biggest customer and the largest nuclear utility in the nation.
2004: USEC picks Piketon over Paducah for a 500-job commercial gas centrifuge plant to replace the outdated Paducah Gaseous Diffusion Plant starting in 2010. Rationale: Piketon already has centrifuge buildings and lacks Paducahís earthquake hazards. USEC intends to apply in August for a plant license.
2006-07: USEC must pay $500 million in federal debt from privatization and find a partner to share the $1.5 billion plant cost to begin construction.
GASEOUS DIFFUSION: Used by the Paducah plant during nearly 52 years of operation, at peak requiring 2 billion watts of electricity daily, more than the state of Texas and twice that of St. Louis. The massive power ó costing hundreds of millions of dollars annually, accounting for 55 percent of the plantís total production expenses ó is needed to run huge machinery in more than 300 acres of cavernous buildings to separate the useful and non-useful isotopes of uranium hexafluoride gas (UF6) for nuclear fuel. The gas is pushed through miles of piping containing billions of holes smaller than two-millionths of an inch.
GAS CENTRIFUGE: Used in Europe for several decades, the process enriches UF6 by spinning it at high speeds in hundreds of tall cylinders. The Energy Department spent nine years building a centrifuge plant at Piketon, then abandoned it in 1985 after brief testing. The department was intent on developing a laser technology called AVLIS that later proved too costly and inefficient.
USEC has decided to re-establish a 500-job gas centrifuge plant in Piketon to replace the Paducah diffusion plant by 2010. Centrifuge uses only about 5 percent of the power needed for the gaseous diffusion process and produces much less waste.