NNSA Picks Amentum to Negotiate a Savannah River Site Lease: A 1 GW Data Center, About 2 GW of Gas Bridging to Nuclear

Where does a gigawatt of data center on federal land get its power, and who pays to hook it up? On Monday the Department of Energy’s National Nuclear Security Administration gave its first partial answer for the Savannah River Site in South Carolina. It selected Amentum, the engineering firm, to enter negotiations for a phased lease covering an AI data center and a dedicated on-site generation source ^[1]. The agency describes the project as “a 1-gigawatt data center and approximately 2-gigawatts of on-site energy generation consisting of natural gas bridging to nuclear energy” ^[1].

That is a selection, not a lease. NNSA says so in its own release: “Selection for negotiations does not constitute a final lease award” ^[1].

What NNSA actually decided on July 20

The selection closes the competition NNSA opened on Sept. 30, 2025, when it issued solicitation RFP-AI-1 for private partners to build and power AI data centers on the site ^[2,3]. NNSA identified 10 tracts totaling 3,103 acres for the program ^[3]. Proposals were due Dec. 5, 2025 ^[2]. Savannah River is one of four DOE sites picked last year to invite private development, along with Idaho National Laboratory, Oak Ridge Reservation and the Paducah Gaseous Diffusion Plant ^[5].

The release says three things about intent. NNSA and Amentum plan to build a data center quickly with enough on-site generation to supply it while making more power available to the grid, to accelerate AI and energy infrastructure, and to use public-private partnerships ^[1]. Any agreement still depends on negotiations, permitting, safety and security evaluations and other federal approvals ^[1].

The consortium is only partly named. DC BLOX, an Atlanta data center and fiber company, announced the same day that it is the digital infrastructure partner “in a development consortium with Amentum and other prominent energy partners” ^[4]. Those energy partners are not identified in either release. Nor is the gas plant’s builder, the reactor design, or which of the 10 tracts the consortium proposed ^[1,4].

Amentum CEO John Heller said the agreement gives the company “the opportunity to partner with the NNSA to deliver infrastructure that will help power the technologies shaping our nation’s future,” according to World Nuclear News ^[5].

Who pays for the gas plant, the reactors and the grid connection

On paper, the developer pays for nearly everything. The solicitation’s lease terms, which the negotiation will start from, put these costs on the selectee:

• Grid connection. The selectee has “full responsibility at its sole cost and expense to find and execute an agreement with the electric utility provider for an appropriate point of transmission-level interconnection, if required” ^[2]. NNSA is not obligated to modify or upgrade site infrastructure to accommodate it ^[2].
• No federal offtake. The solicitation “does not require or otherwise obligate the DOE/NNSA to purchase any service or product from or of the Project” ^[2].
• Site wiring. The selectee may not tie into any DOE/NNSA-owned electrical infrastructure without written approval ^[2].
• Rent and taxes. Consideration for the land is to be “primarily in the form of cash,” backed by a fair market value estimate, and the selectee carries any state and local taxes levied on its lease interest ^[2].
• The end of the lease. A decommissioning bond is required, with demolition and site restoration expected within 18 months after the lease ends ^[2].

NNSA’s release frames the on-site plant as the ratepayer answer. Citing the administration’s Ratepayer Protection Pledge, it says the project pairs the data center with its own generation, “helping ensure the project’s electricity needs are met without shifting costs to existing utility customers” ^[1]. Note what the record does not yet show: the size of any grid connection, and whether power flows in, out or both. The release talks about adding power to the grid ^[1]. The solicitation allowed a first phase “with a rapidly developed data center using grid power,” followed later by expansion and new generation ^[2]. Which model the Amentum proposal follows is not public.

The schedule the solicitation asked for

NNSA set the pace in the solicitation. It expected the data center to take six to 18 months for development, one to two years for construction, and 10 or more years of operations ^[2]. For an integrated project, generation must be available when the data center starts operating; for a phased one, the offeror had to explain how it would power the first phase, “including investment in transmission and related infrastructure” ^[2].

Two reviews sit in front of that clock. NNSA must complete review under the National Environmental Policy Act before signing a lease, or sign one contingent on it ^[2]. Any reactors must be licensed through the Nuclear Regulatory Commission or a DOE authorization, depending on the facility type ^[2]. The solicitation’s security section already anticipates “Contract Security personnel for the Data Center and SMR,” meaning a small modular reactor ^[2].

There is also a land question. The solicitation said the government “envisions leasing approximately 250 to 450 acres” from the 3,103 available ^[2,3]. Whether a 1 GW campus plus about 2 GW of gas and nuclear generation fits in that range, or needs more of the site, the record does not say.

Federal financing comes with a catch the solicitation spells out. A developer seeking a DOE Loan Programs Office loan may face limits if it is “also obtaining rights for the use of federal land at below fair market rates” ^[2]. Market-rate rent and a federal loan can coexist. Discounted land and a federal loan may not.

Where the sides stand

NNSA. Administrator Brandon Williams called the proposal “an opportunity to strengthen America’s leadership in artificial intelligence, expand reliable energy generation, and strengthen our national security,” and said working with the private sector lets the agency “make productive use of federal land while maintaining our commitment to mission delivery” ^[1].

The developers. DC BLOX CEO Jeff Uphues said the company is “honored to join Amentum and this visionary consortium,” and argued that the industry has to change how data centers are powered as well as how they are built ^[4]. The company says it is a founding member of the Palmetto Nuclear Coalition, which World Nuclear News reports also includes Milliken & Company, Google and Nucor ^[4,5].

The watchdog. Savannah River Site Watch, a longtime critic of DOE in South Carolina, called the release “another attempt by DOE to drive policy by a news release” ^[8]. Its questions go straight to the grid: “Would they compete with Dominion & Santee Cooper? How would they wheel electricity into the grid if a utility isn’t involved?” and “What is the role of the SC PSC?” ^[8]. On cost, it wrote that the agency says utility customers won’t bear the cost, “which I doubt,” and that it expects DOE to put costs on taxpayers instead ^[8]. It also questioned why the weapons side of DOE, which it says lacks energy expertise, is running an energy project ^[8].

Local coverage. Augusta’s WRDW reported that tying the facility to its own power source is meant to keep the project from driving up bills for existing customers, and that a deal is not guaranteed ^[6]. Spectrum News noted the site’s history producing plutonium and tritium through the Cold War and its present focus on cleanup and nuclear materials ^[7].

The utilities themselves, and South Carolina’s Public Service Commission, do not appear in any document tied to the selection ^[1,4]. That is the gap SRS Watch is pointing at ^[8].

What I’m watching

The lease terms. NNSA says more on the project and the negotiations will be released “as it becomes available,” with no date given ^[1]. The first useful document will be the one that names the tracts, the acreage and the rent.

The NEPA decision. The solicitation lets NNSA choose the level of environmental review as soon as practicable once it has a proposal in hand ^[2]. Whether that is an environmental assessment or a full impact statement will say a lot about the gas plant’s timeline, and whether an interconnection request to a South Carolina utility shows up first is the other open question.