By Joe Walker firstname.lastname@example.org
On Thursday, the Paducah plant reached a level of 2.25 percent assay, signifying the amount of material in uranium hexafluoride (UF6) that is useful in producing nuclear fuel. More than 99 percent of UF6 is uranium-238, which is not useful in the fuel cycle. The rest is useful uranium-235.
Using powerful electrical equipment and miles of piping, the plant gradually increases the level, or assay, of U-235, traditionally to about 2 percent. The product is then shipped to a plant in Piketon, Ohio, for more enrichment to reach the 4 percent to 5 percent assay desired by nuclear power plants.
Once the Ohio plant is closed, Paducah will have the nation's only uranium enrichment plant. Paducah workers have made changes to be able to enrich to 5.5 percent, and hope to receive Nuclear Regulatory Commission approval for that level in mid-March, said company spokeswoman Elizabeth Stuckle.
"Our Paducah employees have worked very hard on the higher-assay project," she said. "We're very proud of their achievements and very proud of the milestone they've made today."
Stuckle said the increase from 2 percent to 2.25 percent is to prepare to enrich to 2.75 percent, a level the plant was approved for last year, as a step toward 5.5 percent.
"This initial rise in enrichment level is to create an inventory of feed material, which will be used to help increase levels up to 5.5 percent once that is approved," she said. "It allows the assay to increase more easily if we have higher feed material than if lower-level feed is used."
Stuckle said the higher-assay material will be tested regularly until April. In May, the plant will start cutting production to avoid paying high summer costs for electricity. When peak production resumes in the fall, the plant will be ready to enrich uranium at higher levels needed for customers, she said.