Editor’s note: This story replaces the story “NNSA considers new domestic uranium enrichment technology near Oak Ridge” [Nuclear Security & Deterrence Monitor Vol. 27 No. 29], which contained several errors.
The National Nuclear Security Administration wants to establish a pilot program for enriching weapons-grade uranium on American soil by 2030.
It’s a sort of back-to-square-one moment for the nuclear weapons agency, which in 2016 began serious consideration of two different defense-uranium enrichment technologies: one developed by Centrus Corp., Bethesda, Md., another by the Oak Ridge National Laboratory.
In the latest Domestic Uranium Enrichment program, DOE’s semiautonomous National Nuclear Security Administration (NNSA) is seeking industry input on setting up a plant to produce low-enriched uranium by 2030, according to a request for information published last week.
The plant would first produce low-enriched uranium (LEU) of 4.95% uranium-235 and later produce uranium of 93% uranium-235 or greater, according to the notice.
The plant’s first LEU pilot run would begin in 2030 and last at least 24 months, the NNSA wrote in the request for information. At some point after that, possibly after additional LEU pilot runs, the plant would switch over to producing highly enriched uranium, which eventually will be used to produce fuel for naval surface ships and submarines, according to the NNSA notice.
The U.S. currently does not enrich uranium for national defense programs. Under treaty and international agreements, DOE uses only uranium extracted and enriched in the U.S. using U.S.-origin technology. Such uranium is said to be unobligated, meaning its consumer is not obligated to use it only for peaceful purposes.
When the Paducah Gaseous Diffusion Plant in Kentucky closed in 2013, the U.S. government lost its last unobligated uranium-enrichment capability. The only remaining enrichment plant in the U.S., in Eunice, N.M., is owned by Urenco, a European consortium. Under a 1992 agreement with four European governments that the U.S. has been disinclined to revise, Urenco uranium carries a peaceful-use obligation.
To support uranium requirements today and into the 2050s, DOE can rely on Cold War-era stockpiles. When the stockpile runs out, however, the agency will need a new all-domestic enrichment option. The first area of need will be low-enriched uranium to help produce tritium in the Tennessee Valley Authority’s Watts Bar reactors.
One domestic enrichment option that DOE has been bug-shaking for years, using funding from the agency’s Office of Nuclear Energy, is based on technology developed by Centrus Energy Corp. of Bethesda, Md.
Centrus, formerly U.S. Enrichment Corp., operator of the last domestic enrichment plant, built a demonstration cascade at the Department of Energy’s Portsmouth Site near Piketon, Ohio, to demonstrate production of high assay low-enriched uranium (HALEU).
Centrus’ demonstration cascade could enrich just under 1,000 kilograms of HALEU annually, the company has said. The existing cascade, however, contains non-U.S. parts and cannot enrich uranium for national defense programs.
“The demonstration cascade is designed for commercial uses and would require some minor modifications if unobligated production were necessary,” a Centrus spokesperson said Thursday in an email. “However, the technology itself is unobligated and we have the ability to build additional AC100M cascades that could meet the full range of national security requirements.”
Meanwhile, Centrus is on the hook to deliver a 20-kilogram test batch of HALEU to the Department of Energy by Dec. 31. If DOE accepts the material, the agency could trigger options in Centrus’ contract for the company to produce about 900 kilograms of HALEU a year, starting with calendar year 2024. DOE wants the material to help the nuclear industry develop advanced power-generating reactors that require this type of energy-dense fuel.
HALEU contains 19.75% uranium-235 by mass, just below what is conventionally considered highly-enriched uranium.
DOE and the NNSA have sought for years to establish a domestic uranium enrichment program, to no avail. An analysis of alternatives at one point winnowed the possibilities down to technology developed by Centrus and the Oak Ridge National Laboratory, whose respective centrifuge designs were once known as the large and small options.
NNSA formally started an acquisition process for domestic uranium enrichment tech in 2016. The agency then said it was going to pick between the Centrus and Oak Ridge technologies by 2019. It never did. Initially, the agency said it delayed the choice to give Oak Ridge more time to mature its technology.
Editor’s note, Aug. 01, 2023, 9:11 p.m. Eastern time. The story was changed to show that the U.S. uses unobligated uranium for defense purposes because of a treaty agreement, and to correctly identify the owners of the centrifuge designs the NNSA has considered using for future uranium enrichment.
