The Department of Energy’s Office of Nuclear Energy is considering the purchase of up to 25 metric tons annually of high-assay low enriched uranium, the office said Thursday in a request that solicited both information about and sources of the material.

The office envisions at least a six-year contract for the material, to begin “as soon as possible,” according to an explanation appended to the DOE office’s combined sources sought and notice of intent.

The agency wants to buy high assay low enriched uranium (HALEU) produced in the U.S. from newly mined uranium, according to the documents. The natural uranium cannot be mined from lands managed by the federal government, DOE wrote in the notice.

Civilian- and defense-nuclear interests are wound up with the fate of domestically produced HALEU in the U.S. The material is potentially useful for nuclear-energy research and its domestic production could prove out technology and supply chains needed to maintain nuclear weapons.

Centrus Energy Corp., Bethesda, Md., in 2019 got a sole-source DOE contract to build a 16-machine HALEU enrichment cascade at DOE’s Portsmouth Site near Piketon, Ohio. Centrus previously built, and then decommissioned and removed, the American Centrifuged Project in the same Portsmouth building that now hosts the nearly complete HALEU cascade.

The Centrus cascade could, if finished, provide the HALEU that DOE’s Office of Nuclear Energy wants to support commercially unviable research and development for advanced nuclear reactors. Ostensibly, Centrus is competing with others in industry to operate the machines it built under the sole-source contract.

DOE planned to announce the winner of the cascade completion contract by Sept. 30 but had not picked a winner as of Monday. DOE officially opened the operations contract to all offerors in June. The winner will have to finish building the Centrus’ cascade and use it to produce 900 kilograms of HALEU, which by mass would contain 19.75% of the Uranium 235 isotope.

In its amended cascade solicitation, DOE said initial production of HALEU must begin no later than Dec. 31, 2023.

In the HALEU cascade, Centrus is using AC100M technology that the National Nuclear Security Administration (NNSA) was once considering as the basis for a next-generation, domestic enrichment facility that would use only U.S. components and uranium and therefore be suitable for production of uranium for nuclear weapons and warships.

The NNSA has said it needs a new source of domestic low enriched uranium by the late 2040s, initially to produce fuel for the nuclear Navy. Sometime during or after the 2050s, NNSA will also need highly enriched uranium, the agency has said.