Nuclear Power for Data Centers: Restarts, SMRs and Big Tech’s Reactor Deals

Nuclear power for data centers has moved from a niche idea to a central pillar of how hyperscalers plan to power AI. This article walks through every major deal, from reactor restarts and existing-plant contracts to small modular reactors (SMRs), and explains realistic timelines, costs and risks. It belongs to our Data Center Economy hub; for the grid constraints that pushed tech companies toward nuclear, read why power is the new data center bottleneck, and for the climate goals behind these contracts see our guide to data center sustainability and 24/7 clean energy.

Why are Big Tech companies turning to nuclear power for data centers?

They want large volumes of firm, carbon-free electricity that runs 24 hours a day. Nuclear plants operate at very high capacity factors, occupy little land and emit no carbon during operation, which suits AI campuses running near full load around the clock.

Wind and solar remain the cheapest new energy in most markets, and tech companies are still the largest corporate buyers of renewables: the IEA estimates the sector accounted for about 40% of corporate renewable power purchase agreements signed in 2025. But matching a constant data center load hour by hour with weather-dependent supply requires large amounts of storage or backup. Nuclear fills that gap without the emissions of gas.

Grid politics also matter. In tight markets such as PJM, adding gigawatts of new demand without new supply pushes up capacity prices for everyone, a dynamic covered in our article on who pays for data center grid upgrades. Paying to keep reactors running, restart idle ones, uprate existing units or build new ones lets tech companies argue they are adding supply rather than simply consuming it.

Finally, there is the scale of demand. The IEA projects global data center electricity use could roughly double from about 415 TWh in 2024 to around 945 TWh by 2030. It expects renewables to meet nearly half of that growth, with nuclear’s contribution growing mainly after 2030 as SMRs come online. Tech firms are signing contracts now to secure a place in that later wave.

What is the Crane Clean Energy Center and when will it restart?

Crane is the renamed Three Mile Island Unit 1 in Pennsylvania, which Constellation is restarting to supply Microsoft under a 20-year power purchase agreement signed in 2024. Constellation says it still expects the 835 MW reactor to return in 2027.

Unit 1, unaffected by the 1979 accident at Unit 2, shut in 2019 for economic reasons. Constellation announced the restart on 20 September 2024 with an original target of 2028 and plans to invest about $1.6 billion. In November 2025 the Department of Energy’s Loan Programs Office announced a $1 billion loan to support the project, and Constellation has said the plant’s main generator and turbines have operated successfully during preparations.

The schedule’s main risk is the grid, not the reactor. According to the American Nuclear Society, a PJM analysis suggested Crane might not be able to connect until 2031. Constellation has asked FERC to allow it to transfer capacity interconnection rights from its Eddystone generating station to Crane, and chief executive Joseph Dominguez said in April 2026 that the company continues to expect a 2027 start. Whether that holds will be one of the most closely watched tests of whether reactor restarts can outrun interconnection queues.

The plant will feed the PJM grid, with Microsoft buying the output and its clean attributes, avoiding the fights that have hit physically co-located deals.

How does the Talen–Amazon Susquehanna deal work?

Amazon Web Services agreed in June 2025 to buy up to 1,920 MW from Talen Energy’s 2.5 GW Susquehanna nuclear plant in Pennsylvania through 2042. POWER Magazine valued the 17-year contract at about $18 billion, or up to roughly $1.4 billion a year at full volume.

The deal is a case study in how regulation shapes nuclear-data center structures. Amazon originally bought Talen’s adjacent data center campus in 2024 and took about 300 MW directly from the plant behind the meter. When PJM filed to raise that co-located load to 480 MW, with a path to 960 MW, FERC rejected the amendment on a 2–1 vote in November 2024, finding PJM had not justified departing from standard transmission rules.

Rather than litigate, Talen restructured. Under the new front-of-meter model, Talen acts as AWS’s licensed retail electricity supplier, and power flows across the grid via PPL Electric Utilities. The switch was scheduled for the plant’s spring 2026 refuelling outage. Deliveries ramp from 840–1,200 MW by 2029 to 1,680–1,920 MW by 2032. The companies also agreed to evaluate uprates and possible SMRs at or near Talen sites, though Talen’s chief executive described SMRs as an option for years 11 to 15 of the relationship with no capital committed.

What nuclear deals have Meta and Google signed?

Meta has signed a 20-year PPA for Constellation’s Clinton plant and, in January 2026, deals with Vistra, Oklo and TerraPower worth up to 6.6 GW. Google backed the Duane Arnold restart in Iowa and Kairos Power’s first power-producing reactor in Tennessee.

Meta: from one plant to a 6.6 GW portfolio

In June 2025 Meta signed a 20-year agreement for the 1,121 MW output of Constellation’s Clinton Clean Energy Center in Illinois, starting in June 2027 and including a 30 MW uprate. On 9 January 2026 it went much further. According to the American Nuclear Society, Meta agreed to support Vistra uprates totalling 433 MW at the Perry, Davis-Besse and Beaver Valley plants by the early 2030s; to back an Oklo advanced nuclear campus in Pike County, Ohio, targeting up to 1.2 GW delivered into PJM as early as 2030; and to fund two TerraPower Natrium units, each a 345 MW sodium-cooled reactor with molten-salt storage able to boost output to 500 MW, with rights to six more by 2035. Together the deals could see Meta finance up to 6.6 GW of new and existing capacity by 2035.

Google: restarts plus advanced reactors

In October 2025 Google agreed to buy the output of NextEra Energy’s Duane Arnold Energy Center in Iowa under a 25-year PPA, supporting a restart of the 615 MW plant, Iowa’s only nuclear station. NextEra expects it back online around the end of 2028 or early 2029, subject to Nuclear Regulatory Commission approvals expected before January 2028, and the DOE closed a loan of up to $1.9 billion for the restart on 8 September 2026.

Google is also the anchor customer of Kairos Power, which is developing a fluoride salt-cooled, high-temperature reactor. Kairos broke ground on Hermes 2 in Oak Ridge, Tennessee, on 17 April 2026, and after a power purchase agreement among Kairos, the Tennessee Valley Authority and Google, it raised the unit’s planned output to 50 MWe. Kairos expects Hermes 2 to start operating by 2030, making it one of the first advanced reactors to supply a tech company through a utility.

What are small modular reactors and which SMR companies are tech firms backing?

Small modular reactors are nuclear units typically below about 300 MW that are designed for factory fabrication and serial deployment. Amazon backs X-energy, Google backs Kairos, Meta backs Oklo and TerraPower, and the IEA counts about 45 GW of conditional SMR offtake agreements with data center operators.

The IEA’s 2026 report said the pipeline of conditional offtake agreements between data center operators and SMR developers grew from 25 GW at the end of 2024 to 45 GW. That is a large number on paper, but most agreements depend on designs that have not yet been licensed or built at commercial scale. The promise of SMRs is that standardized, smaller units will reduce the cost overruns and delays that plagued large reactors; the risk is that first-of-a-kind units will repeat them.

Amazon and X-energy

Amazon has pledged to buy up to 5 GW of power from X-energy reactors by 2039 and led a $500 million funding round in the company. X-energy’s Xe-100 is a high-temperature gas-cooled reactor of about 80 MW electric per module, typically grouped in four-packs of 320 MW. The flagship Cascade project near Richland, Washington, is planned at up to 960 MW in three phases; Amazon said it expected regulatory approval to begin construction by the end of 2026, with operation in the 2030s. X-energy listed on Nasdaq in April 2026, raising about $1.02 billion at $23 a share, above its marketed range.

Oklo and TerraPower

Oklo, backed by Meta’s Ohio deal, is developing the Aurora Powerhouse, a liquid-metal-cooled fast reactor. Its first unit at Idaho National Laboratory, designed for up to 75 MW, broke ground in September 2025. After the NRC rejected Oklo’s original application in 2022, the company has been in extensive pre-application work, and NucNet reported in April 2026 that Aurora-INL is now expected to begin operations in 2028. TerraPower’s Natrium design pairs a 345 MW reactor with molten-salt storage, which lets output flex up to 500 MW to follow demand.

Source: Company announcements as reported by the American Nuclear Society, POWER Magazine, The Register, The Next Web and Constellation Energy (2024–2026).

How long will it take for new reactors to power data centers?

Restarts and uprates can deliver within two to five years, but new reactors take much longer. Most SMR projects backed by tech companies target first power between 2028 and the mid-2030s, and history suggests first-of-a-kind schedules often slip.

Licensing is the first gate. The NRC must approve designs, construction permits and operating licences, and only a handful of advanced designs have reached construction. LBNL’s analysis of interconnection queues shows nuclear has historically had one of the better completion rates once queued, at about 18% of capacity for requests filed between 2000 and 2020, but only around 10 GW of nuclear was actively seeking interconnection at the end of 2025.

Supply chains are the second gate. Advanced reactors such as Kairos, X-energy and TerraPower rely on high-assay low-enriched uranium (HALEU) or specialized TRISO fuel, which is not yet produced at scale in the West. Skilled labour, forgings and nuclear-grade components are also constrained. And then there is the grid: as Crane shows, even a ready reactor still needs an interconnection slot.

Hence the layered strategy: existing-plant contracts and restarts for this decade, uprates at known sites, and SMRs as long-dated options.

What does nuclear power cost compared with other options for data centers?

Nuclear is generally more expensive per megawatt-hour than new wind or solar but competitive with other firm clean options once round-the-clock reliability is valued. Exact prices in tech deals are rarely disclosed; Talen-Amazon is a rare exception at about $18 billion over 17 years.

Dividing Talen’s disclosed figures gives a sense of scale: up to about $1.4 billion a year for up to 1,920 MW of round-the-clock supply. That price bundles energy, capacity and clean attributes, and it reflects the scarcity value of existing nuclear in a tight market. For restarts, the economics depend on federal support: the DOE loans of $1 billion for Crane and up to $1.9 billion for Duane Arnold reduce financing costs substantially.

For new SMRs, costs are still estimates. First units typically carry a premium that developers hope will fall as they build fleets. Tech companies can tolerate higher prices because power is a modest share of an AI data center’s total cost compared with GPUs and other IT equipment, as our analysis of data center operating costs shows. What they value most is certainty of supply and carbon-free attributes.

Do nuclear deals with data centers raise prices for other customers?

It depends on structure. Deals that add new or restarted capacity increase supply, while contracts that redirect existing output to one customer can tighten markets for everyone else. Regulators have scrutinized behind-the-meter arrangements most closely for this reason.

FERC’s November 2024 rejection of the expanded Talen-Amazon co-location deal reflected concerns, raised by utilities and consumer advocates, that co-located loads might use the grid’s reliability services without paying for them, and that diverting existing nuclear output could raise capacity prices. FERC’s December 2025 order directing PJM to create new transmission services for co-located load, and its June 2026 show-cause orders to six grid operators, aim to settle those questions. Meanwhile, PJM’s capacity auctions have cleared at or near the price cap for three consecutive years, keeping the issue politically sensitive, as covered in our analysis of data centers and electricity prices.

What should businesses watch next in nuclear power for data centers?

Watch three milestones: whether Crane restarts in 2027, whether the NRC issues construction permits for SMRs such as Amazon’s Cascade project and Oklo’s Aurora on schedule, and whether HALEU fuel supply scales. Each will show whether nuclear can keep pace with AI demand.

Also watch for more DOE loans, utility-led structures like Kairos-TVA-Google, and tech equity stakes in reactors. Interest is rising abroad too; our coverage of Asia-Pacific data center investment tracks how power constraints shape siting there.

For now, the realistic picture is a bridge: existing reactors and restarts supply a meaningful but limited slice of AI demand through 2030, while gas and renewables do most of the work. If SMRs deliver on cost and schedule in the early 2030s, nuclear could become a much larger part of the data center energy mix in the following decade.

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