The National Nuclear Security Administration (NNSA) is adding about $10 million of work to the first phase of Nuclear Fuel Services’ contract to purify uranium for the secondary stages of nuclear weapons, according to a procurement note published Monday.

The new work, which the nuclear-weapons agency did not describe in Monday’s sole source justification, brings the value of the first stage of Nuclear Fuel Services’ (NFS) three-year, sole-source uranium conversion and purification contract to about $67.5 million. 

The added contract scope “will allow NFS to improve the fidelity of the purification and conversion process design and ensure continued and consistent effort by NFS throughout Phase II contract negotiations,” the NNSA wrote in

the notice published Monday.

Under the contract, NFS, a BWX Technologies [BWXT] subsidiary in Erwin, Tenn., will convert impure highly enriched uranium metals and oxides in the NNSA stockpile into purified uranium buttons. The fissile metal powers the secondary stages of nuclear weapons.

The NNSA usually handles those tasks at the Y-12 National Security Complex in Oak Ridge, Tenn., but has had to outsource the work to accommodate expected outages at the site, where the agency is in the middle of widespread upgrades to its uranium processing infrastructure. 

NFS will serve as a bridge to new electrorefining technology being installed at Y-12. In 2023, the NNSA planned to replace the old wet-chemistry conversion and purification equipment at the site. After the switch, NNSA has said, Y-12 will be without a means of converting uranium oxide to uranium metal. NFS’ contract runs for three years.

The NNSA is building an entirely new uranium complex at Y-12, anchored by the Uranium Processing Facility being built by Bechtel National under a subcontract to site prime Consolidated Nuclear Security, a Bechtel-led team. In 2022, the NNSA said the facility would be delayed by about two years, into 2027, because of labor and supply-chain problems arising at least in part from the COVID-19 pandemic.