SoftBank to build massive AI datacenter on former US nuclear weapons site

The Register / 3/24/2026

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Key Points

  • SoftBank plans to build a massive AI-focused data center on a former US nuclear weapons site, positioning the location as a large-scale compute hub.
  • The project is described as involving a roughly 10GW server farm capacity (and additional generation) alongside major new electrical infrastructure to support AI workloads.
  • A reported $4.2B grid upgrade is central to enabling the site’s power needs, highlighting how AI datacenter growth is increasingly constrained by electricity and grid capacity.
  • The article notes that uranium cleanup costs are being covered by another party, underscoring the public/legacy-environment responsibilities tied to repurposing sensitive sites.
  • The initiative signals continued “signals-early” momentum for hyperscale AI infrastructure expansion, with significant implications for power planning, site remediation, and regional permitting.

SoftBank to build massive AI datacenter on former US nuclear weapons site

10GW server farm, 10GW of new generation, and $4.2bn grid upgrade. And someone else is paying for the uranium cleanup

Mon 23 Mar 2026 // 17:29 UTC

Softbank's SB Energy is redeveloping Department of Energy (DoE) land in Ohio for a massive datacenter campus, adding extra generation facilities and power infrastructure alongside it.

The Japanese investment giant's digital infrastructure and energy arm is leasing federal land at the former Portsmouth Gaseous Diffusion Plant in Piketon, Ohio, to build a 10-gigawatt (GW) server farm.

SB Energy will also build 10 GW of new generation capacity, at least 9.2 GW of it gas-fired, feeding both the local grid and the datacenter. Separately, SB Energy and American Electric Power (AEP) Ohio have struck a $4.2 billion deal to upgrade and expand electrical transmission infrastructure across Southern Ohio, a move both parties claim will lower utility bills for local homes and businesses. AEP expects power to reach the site by 2029.

The project is framed as consistent with President Trump's Ratepayer Protection Pledge, which aims to shield consumers from price increases driven by surging AI infrastructure demand.

According to the DoE, SB Energy has also committed to funding accelerated cleanup of the Portsmouth site, which was formerly used to produce enriched uranium for both civilian nuclear power and the US weapons program.

SoftBank has announced a "Portsmouth Consortium" of companies and financial institutions interested in participating, including Japanese firms Hitachi, Mitsubishi Electric, Toshiba, TDK and Sumitomo Mitsui Banking, alongside US names Bechtel, Morgan Stanley, Goldman Sachs and J.P. Morgan.

The same site has separately been chosen by nuclear developer Oklo, in a joint venture with Centrus Energy, for a uranium processing facility, and by Meta as the location for a nuclear power campus targeting up to 1.2 GW of baseload power.

US Energy Secretary Chris Wright said the US Administration is using its assets, including federal land, to add power generation, create jobs, and ensure the country wins the AI race.

"By bringing new power online and upgrading our existing infrastructure, this investment supports the AI boom and cutting-edge technologies while strengthening our energy system and helping keep costs down for the American people," he said.

SoftBank Group chairman and CEO Masayoshi Son, said: "AI will transform every industry, and the PORTS Technology Campus will help deliver the next-generation infrastructure needed to unlock those breakthroughs." ®

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