SMR timing

Introduction

Small modular reactors, or SMRs, sound almost perfectly designed for the AI era. Technology companies want huge amounts of steady low-carbon electricity for data centres that run day and night. SMRs promise factory-built nuclear reactors that are smaller, potentially faster to deploy, and easier to place near major computing hubs. In theory, they could help support a future in which AI systems become vastly more capable without driving a parallel surge in fossil-fuel use.

SMR timing illustration 1 The problem is timing. AI infrastructure is expanding on software and semiconductor timescales measured in months and a few years, while nuclear projects still move on regulatory, industrial and grid-planning timescales measured in decades. Many of the reactors discussed in presentations and partnership announcements do not yet exist commercially. Even projects involving conventional reactors are running into licensing reviews, transmission bottlenecks and supply-chain constraints. The result is a growing gap between how quickly AI companies want electricity and how slowly nuclear systems can realistically arrive. [IEA]iea.orgIEAExecutive summary – Energy and AI – AnalysisThe first small modular reactors come online around 2030. Data centres are one of several… [Reuters]reuters.comus nuclear plants wont power up big techs ai ambitions right away 2024 09 24ReutersUS nuclear plants won't power up Big Tech's AI ambitions…24 Sept 2024 — A plan by Microsoft to use the restart of a Three Mile…

Why AI firms want reactors near data centres

AI companies increasingly care less about electricity prices alone and more about guaranteed access to continuous power. Large AI training clusters are expensive capital assets. If thousands of advanced chips sit idle because electricity is unavailable, the economics deteriorate quickly.

[That makes nuclear power attractive for three main reasons:]facebook.comReutersMicrosoft has agreed to pay an energy company to revive the shuttered Three Mile Island nuclear power plant in Pennsylvania. And t…

It provides stable “firm” power around the clock.
It produces very low operational carbon emissions.
It can support extremely energy-intensive facilities without relying entirely on congested regional grids.

For firms trying to build ever larger AI systems, this matters strategically. The International Energy Agency expects data-centre electricity demand to rise sharply as AI adoption expands, with nuclear likely contributing part of the new generation mix. The agency notes that the first SMRs are expected to come online around 2030, not immediately. [IEA]iea.orgIEAExecutive summary – Energy and AI – AnalysisThe first small modular reactors come online around 2030. Data centres are one of several…

This helps explain why Microsoft backed the restart of a reactor at Three Mile Island, why Google signed agreements linked to future SMR development, and why Amazon has explored reactor partnerships near future AI infrastructure. These companies increasingly view electricity access as a limiting factor on AI scaling itself. Reuters [GIS Reports]gisreportsonline.comGIS ReportsWhat is holding up progress on small modular reactors?25 Nov 2025 — Similarly, Google has partnered with Kairos Power to bring…

There is also a geographical reason for the interest. Many major AI data-centre regions already face transmission congestion and grid-connection delays. A reactor located near a hyperscale campus could reduce dependence on overstressed transmission networks and potentially offer more predictable long-term power contracts. The US Department of Energy has argued that advanced reactors could eventually be built alongside data centres and other critical infrastructure. [energy.gov]energy.govadvantages and challenges nuclear powered data centers6. Existing nuclear…Read more…

In the broader “AI bloom” vision, energy abundance matters because advanced AI only becomes civilisation-scale infrastructure if societies can sustain enormous computing capacity without destabilising energy systems or climate targets. Nuclear power appeals to AI firms partly because it hints at a path where intelligence expansion is not tightly constrained by intermittent electricity supply.

The licensing, cost and fuel bottlenecks

The central question is not whether SMRs are theoretically useful. It is whether they can arrive fast enough to matter for the current AI buildout.

So far, the evidence points to serious timing problems.

Nuclear timelines still move slowly

Most advanced SMR designs are still in licensing, pre-commercial testing or early demonstration phases. Few have completed the full path from concept to mass deployment.

Even projects involving existing reactors are moving slowly. Microsoft’s deal to support the restart of Three Mile Island became one of the most visible AI-nuclear partnerships precisely because restarting an old plant may be faster than building a new one from scratch. Yet the project has still encountered regulatory reviews, transmission delays and expensive refurbishment work. [Reuters]reuters.comMicrosoft deal propels Three Mile Island restart, with keyReutersMicrosoft deal propels Three Mile Island restart, with key…September 20, 2024 — 21 Sept 2024 — Constellation Energy (CEG.O) and…Published: September 20, 2024 [Reuters]reuters.comus targets 5 gw more nuclear power through low cost finance reeii 2026 04 21US targets 5 GW more nuclear power through low-cost…Apr 21, 2026 — Vistra Corp in January announced a 20-year PPA to provide more tha… [Reuters]reuters.comReutersUS may decide on Three Mile Island restart in June…7 days ago — Constellation is aiming to revive its nuclear power plant in P…

One revealing detail is that the delays are not purely about reactor engineering. Grid interconnection queues, transmission upgrades and federal approvals may postpone power delivery for years even after physical work progresses. Reuters reported that initial feedback from grid operator PJM suggested the restarted plant might not fully deliver power until 2031 under existing grid processes. [Reuters]reuters.comConstellation to ask regulators for help speeding up Three…Mar 31, 2026 — Constellation to ask regulators for help speeding up Three M…

That mismatch matters because AI demand is rising now, not in the early 2030s.

SMRs remain commercially unproven

Another obstacle is that many headline SMR projects have not yet demonstrated commercial economics at scale.

NuScale, one of the most prominent US SMR developers, saw its planned Utah project collapse in 2023 after estimated costs rose sharply and customers withdrew. Critics argue that early SMR projects risk repeating the long history of cost overruns associated with conventional nuclear construction. [Utility Dive]utilitydive.comnuscale uamps project small modular reactor ramanasmrThe collapse of NuScale's project should spell the end for…31 Jan 2024 — On a per megawatt basis, the estimated cost of the CAREM-25 S…

Supporters of SMRs argue that factory manufacturing and modular construction could eventually reduce costs dramatically. But that future depends on achieving large production volumes and regulatory standardisation that do not yet exist. Early projects are likely to remain expensive because they lack the manufacturing scale that the SMR concept depends on in the first place.

This creates a circular problem:

SMRs become cheaper only after many reactors are built.
But few reactors are built because early projects are expensive and uncertain.

AI companies may help break that cycle because hyperscalers can sign long-term electricity agreements large enough to support financing. Yet that still does not guarantee rapid deployment.

Fuel and supply-chain constraints

The fuel system is another major bottleneck that receives less public attention.

Several advanced reactor designs depend on forms of enriched uranium that currently have limited supply chains outside Russia. After Russia’s invasion of Ukraine, Western governments imposed restrictions and began trying to rebuild domestic fuel capacity. Reuters reported that fuel and component bottlenecks are already complicating nuclear expansion plans tied to AI infrastructure. [Reuters]reuters.comIn a recent filing, the company emphasized the need for federal energy regulators to approve waivers that would allow the facility to qui…

Advanced reactors also require specialised manufacturing capacity for pressure vessels, turbines, cooling systems and reactor-grade materials. Nuclear supply chains cannot currently scale at anything close to semiconductor-industry speed.

That matters because the AI industry is accustomed to rapid iteration. Companies can deploy a new model globally within days. Nuclear infrastructure cannot evolve on that cadence.

SMR timing illustration 2

What could realistically arrive in the 2030s

The most plausible near-term outcome is not a world where every AI campus gets its own dedicated SMR by 2030. It is a more uneven mix of restarts, uprates, pilot reactors and selective deployments.

Existing nuclear plants may matter more than new SMRs

In the late 2020s, the fastest nuclear gains for AI companies are likely to come from extending or restarting conventional reactors rather than deploying entirely new modular systems.

The Three Mile Island restart illustrates this logic. The reactor already exists, has grid connections, and previously operated commercially. Even then, restarting it remains difficult. But it is still potentially quicker than licensing and building a first-of-its-kind SMR campus from scratch. [Reuters]reuters.comConstellation exec says grid operator told company Three…26 Mar 2026 — Constellation is working to resume operations at the nuclear p… [Reuters]reuters.comthree mile island nuclear plant gears up big tech reboot 2024 10 22Three Mile Island nuclear plant gears up for Big Tech reboot22 Oct 2024 — Restart work is expected to begin in Q1 2025 · Constellation ha…

Other technology firms appear to be exploring similar strategies through power-purchase agreements with existing nuclear operators. In practical terms, this may do more to support AI expansion in the 2020s than futuristic reactor designs.

First-wave SMRs may serve niche roles

Some early SMRs could still appear in the 2030s, especially in regions with strong government backing and simplified licensing pathways.

Google’s partnership with Kairos Power aims for reactors around 2030, while Amazon-backed projects involving X-energy target construction late in the decade and operation sometime in the 2030s. [GIS Reports]gisreportsonline.comGIS ReportsWhat is holding up progress on small modular reactors?25 Nov 2025 — Similarly, Google has partnered with Kairos Power to bring… [Tom's Hardware]tomshardware.comAnnounced on October 16, the Cascade Advanced Energy Facility will be built in partnership with Energy Northwest and utilize Xe-100 small…

But these projects are best understood as demonstrations and industrial footholds rather than evidence of immediate large-scale transformation.

The first successful SMRs may be especially useful in cases where:

Grid congestion is severe.
Land is available near industrial campuses. [* Governments actively support advanced nuclear deployment.]iaea.orgsuch as small modular reactors (SMRs) to provide clean, reliable and flexible power.Read more… [* Data-centre operators value energy security more than lowest-cost power.]reuters.comus targets 5 gw more nuclear power through low cost finance reeii 2026 04 21US targets 5 GW more nuclear power through low-cost…Apr 21, 2026 — Vistra Corp in January announced a 20-year PPA to provide more tha…

Military infrastructure, remote industrial sites and strategically important AI campuses may therefore become early adopters before broad commercial rollout.

The longer-term case is stronger than the near-term case

Ironically, the strongest argument for SMRs may lie beyond the immediate AI power crunch.

If advanced AI continues expanding through the 2030s and 2040s, electricity demand could eventually become enormous. In that world, societies may need far more firm low-carbon power than today’s grids can provide through renewables alone. SMRs could become valuable not because they solve the next five years, but because they help sustain decades of growing computational infrastructure.

That possibility matters to the broader AI abundance argument. A civilisation with dramatically more scientific discovery, automated industry, robotics and AI-assisted research may ultimately require energy systems that are cleaner, denser and more reliable than those available today.

But there is a crucial distinction between long-term strategic relevance and near-term deployment reality.

Right now, the evidence suggests that SMRs are unlikely to solve the immediate AI electricity bottleneck at the speed many technology narratives imply. Most AI growth through the second half of the 2020s will probably still rely on existing grids, natural gas expansion, renewable buildouts, transmission upgrades and conventional nuclear assets rather than large fleets of newly built modular reactors. [IEA]iea.orgIEAExecutive summary – Energy and AI – AnalysisThe first small modular reactors come online around 2030. Data centres are one of several… [Reuters]reuters.comshut three mile island nuclear plant may restart 2027 owner says 2025 06 25The move follows a 20-year power purchase agreement with Microsoft, aimed at supporting the tech giant’s expanding AI infrastructure. The…

The deeper tension between AI speed and infrastructure speed

The excitement around SMRs reveals a larger tension inside the AI boom itself.

Digital technologies can scale extraordinarily quickly. Physical infrastructure cannot.

Training algorithms, deploying software and designing chips all move far faster than permitting power plants, constructing transmission lines or expanding fuel supply chains. That mismatch may become one of the defining economic constraints of advanced AI development.

The optimistic “AI bloom” vision often assumes that intelligence acceleration eventually helps solve major material bottlenecks through faster science, better engineering and more efficient systems. Nuclear advocates argue that AI itself could eventually improve reactor design, grid optimisation and construction productivity.

But the current moment shows that abundance still depends on stubborn physical realities:

Steel, concrete and transmission lines.
Skilled nuclear engineers and regulators.
Fuel enrichment and manufacturing capacity.
Public trust and political approval.
Long construction timelines.

In other words, the future of advanced AI may depend not only on breakthroughs in machine intelligence, but on whether societies can build real-world energy systems quickly enough to support it.

SMR timing illustration 3

Endnotes

Source: iea.org
Link: https://www.iea.org/reports/energy-and-ai/executive-summary
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IEAExecutive summary – Energy and AI – AnalysisThe first small modular reactors come online around 2030. Data centres are one of several...
Source: reuters.com
Title: us nuclear plants wont power up big techs ai ambitions right away 2024 09 24
Link: https://www.reuters.com/technology/artificial-intelligence/us-nuclear-plants-wont-power-up-big-techs-ai-ambitions-right-away-2024-09-24/
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ReutersUS nuclear plants won't power up Big Tech's AI ambitions...24 Sept 2024 — A plan by Microsoft to use the restart of a Three Mile...
Source: reuters.com
Title: Microsoft deal propels Three Mile Island restart, with key
Link: https://www.reuters.com/markets/deals/constellation-inks-power-supply-deal-with-microsoft-2024-09-20/
Source snippet
ReutersMicrosoft deal propels Three Mile Island restart, with key...September 20, 2024 — 21 Sept 2024 — Constellation Energy (CEG.O) and...

Published: September 20, 2024
Source: energy.gov
Title: advantages and challenges nuclear powered data centers
Link: https://www.energy.gov/ne/articles/advantages-and-challenges-nuclear-powered-data-centers
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6. Existing nuclear...Read more...
Source: reuters.com
Title: us targets 5 gw more nuclear power through low cost finance reeii 2026 04 21
Link: https://www.reuters.com/business/energy/us-targets-5-gw-more-nuclear-power-through-low-cost-finance–reeii-2026-04-21/
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US targets 5 GW more nuclear power through low-cost...Apr 21, 2026 — Vistra Corp in January announced a 20-year PPA to provide more tha...
Source: reuters.com
Link: https://www.reuters.com/business/energy/us-may-decide-three-mile-island-restart-june-constellation-execs-say-2026-05-11/
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ReutersUS may decide on Three Mile Island restart in June...7 days ago — Constellation is aiming to revive its nuclear power plant in P...
Source: reuters.com
Link: https://www.reuters.com/business/energy/constellation-ask-regulators-help-speeding-up-three-mile-island-nuclear-power-2026-03-31/
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Constellation to ask regulators for help speeding up Three...Mar 31, 2026 — Constellation to ask regulators for help speeding up Three M...
Source: reuters.com
Link: https://www.reuters.com/business/energy/delayed-transmission-projects-blocking-speedy-three-mile-island-restart-2026-04-06/
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In a recent filing, the company emphasized the need for federal energy regulators to approve waivers that would allow the facility to qui...
Source: reuters.com
Link: https://www.reuters.com/business/energy/ceraweek-constellation-exec-says-grid-operator-told-company-three-mile-island-2026-03-26/
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Constellation exec says grid operator told company Three...26 Mar 2026 — Constellation is working to resume operations at the nuclear p...
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SMR market is NuScale. The company recently received approval for a revised, larger design from the U.S...
Source: reuters.com
Title: three mile island nuclear plant gears up big tech reboot 2024 10 22
Link: https://www.reuters.com/business/energy/three-mile-island-nuclear-plant-gears-up-big-tech-reboot-2024-10-22/
Source snippet
Three Mile Island nuclear plant gears up for Big Tech reboot22 Oct 2024 — Restart work is expected to begin in Q1 2025 · Constellation ha...
Source: reuters.com
Title: shut three mile island nuclear plant may restart 2027 owner says 2025 06 25
Link: https://www.reuters.com/sustainability/climate-energy/shut-three-mile-island-nuclear-plant-may-restart-2027-owner-says-2025-06-25/
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The move follows a 20-year power purchase agreement with Microsoft, aimed at supporting the tech giant’s expanding AI infrastructure. The...
Source: reuters.com
Title: Time to go nuclear?
Link: https://www.reuters.com/sustainability/climate-energy/time-go-nuclear-inside-battle-power-ai–ecmii-2025-12-17/
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Inside the battle to power AI9 Jan 2026 — Some hyperscalers have embraced conventional reactors: Microsoft agreed last year to restart Th...
Source: reuters.com
Title: us loans constellation 1 billion three mile island reactor reboot 2025 11 18
Link: https://www.reuters.com/business/energy/us-loans-constellation-1-billion-three-mile-island-reactor-reboot-2025-11-18/
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US loans Constellation $1 billion for Three Mile Island...18 Nov 2025 — Constellation signed a deal in late 2024 with Microsoft (MSFT.O)...
Source: commonfund.org
Link: https://www.commonfund.org/cf-private-equity/data-center-and-ai-power-demand-will-nuclear-be-the-answer
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Data Center and AI Power Demand – Will Nuclear Be the...Jul 31, 2025 — Microsoft entered into a 20-year PPA, also with Constellation, to...
Source: gisreportsonline.com
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GIS ReportsWhat is holding up progress on small modular reactors?25 Nov 2025 — Similarly, Google has partnered with Kairos Power to bring...
Source: tomshardware.com
Link: https://www.tomshardware.com/tech-industry/amazon-unveils-plans-for-modular-nuclear-plant-in-washington
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Announced on October 16, the Cascade Advanced Energy Facility will be built in partnership with Energy Northwest and utilize Xe-100 small...
Source: utilitydive.com
Title: nuscale uamps project small modular reactor ramanasmr
Link: https://www.utilitydive.com/news/nuscale-uamps-project-small-modular-reactor-ramanasmr-/705717/
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The collapse of NuScale's project should spell the end for...31 Jan 2024 — On a per megawatt basis, the estimated cost of the CAREM-25 S...
Source: facebook.com
Link: https://www.facebook.com/Reuters/posts/-tech-giants-are-getting-into-the-power-business-microsoft-is-restarting-a-nucle/1321145036542892/
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ReutersMicrosoft has agreed to pay an energy company to revive the shuttered Three Mile Island nuclear power plant in Pennsylvania. And t...
Source: iaea.org
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such as small modular reactors (SMRs) to provide clean, reliable and flexible power.Read more...
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to Restart a Nuclear Reactor2 Oct 2024 — Tech giant Microsoft will buy the power produced at Three Mile Island to help match the power co...

Additional References

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SMRs: Still Too Expensive, Too Slow and Too Riskyby ES Figure · Cited by 10 — First, when NuScale's proposed SMR project with UAMPS was c...
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Small Modular Reactors (SMRs) for AI/LLM Datacenters11 Nov 2025 — Executive Summary Small Modular Reactors (SMRs) represent an emerging s...
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Three Mile Island nuclear reactor to restart to power Microsoft AI operations. 20 Sept 2024. End of an era: closure of nuclear...Read more...
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Three Mile Island nuclear reactor to restart to power...20 Sept 2024 — A nuclear reactor at the notorious Three Mile Island site in Penn...