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Is nuclear power making a comeback?

Nuclear power is booming again on AI demand, but high costs and an ageing US fleet mean growth depends on restarts and renewals, not new builds.

Updated 15 hours ago5 min readVersion 4
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Covers: New reactors, restarts and small modular reactors (SMRs), with a focus on the US and global outlook to about 2035. Nuclear weapons and waste policy are only mentioned where they affect deployment.

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Image: Constellation Energy

The short answer

Evidence-backed AI-organised, reviewed

Nuclear is having its strongest moment in decades: record global generation, over 70 GW under construction, and tech companies signing deals to restart old plants and buy power from future small reactors to run AI data centres. Whether that becomes a real build-out depends on cost: recent Western projects like Vogtle ran years late and far over budget, and small modular reactors haven't yet proven they can be built cheaply. In the US, the existing fleet is large (96 reactors, about 98 GW, 18.6% of generation in 2024) but ageing, with 41 reactors already permanently shut down and licences for 22 reactors due to expire before the end of 2029 if not renewed, so near-term growth leans heavily on restarts, uprates and licence renewals rather than new builds.12345

What this rests on6 independent sources · 4 versions
  • Evidence 18
  • Interpretation 5

In brief

  1. Global nuclear generation was set to reach a record in 2025, with more than 70 GW under construction.1

    Evidence-backed
  2. Microsoft's 20-year deal will restart an 835 MW Three Mile Island unit, expected online in 2028.2

    Evidence-backed
  3. Google aims for a first Kairos SMR by 2030 and up to 500 MW by 2035.3

    Evidence-backed
  4. Cost overruns remain the main barrier; SMRs still need to prove they can be built affordably.14

    Evidence-backed
  5. In the US, near-term capacity turns on the existing fleet: 96 reactors at about 98 GW, 41 already shut down, and 22 licences expiring before the end of 2029 if not renewed.5

    Evidence-backed

At a glance

The picture in numbers

Live · updated just now

IEA 2025 report projection

70 GW

70 GW: Nuclear capacity under construction worldwide1
About 98 GW net capacity

96 reactors

96 reactors: US commercial reactors in the existing fleet5
As of July 2026

41 reactors

41 reactors: US reactors already permanently shut down5
If not renewed

22 licences

22 licences: US reactor licences expiring before end of 20295

The evidence behind it

6 sources
  • Other studies and data1
  • Background5

Published in 2024 and 2025

Sources on this page by kind and year
SourceKindYear
The Path to a New Era for Nuclear EnergyBackground2025
Google signs advanced nuclear clean energy agreement with Kairos PowerBackground2024
Plant Vogtle Unit 4 begins commercial operationOther studies and data2024
Constellation to launch Crane Clean Energy Center, restoring jobs and carbon-free power to the gridBackground2024
Nuclear power in the United States (Wikipedia)BackgroundUnknown
Nuclear power debate (Wikipedia)BackgroundUnknown

The community around it

Contributions
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People
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Following
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Nobody has added anything yet. Experience, evidence or a different view would show up here.

What it means for you

Which fits you?

Pick the situation closest to yours. Each answer says what it rests on.

If you're following the AI power-demand story

Watch restarts of existing plants first: they're the fastest path to new nuclear supply, as with the Crane restart planned for 2028.2

Evidence-backed

If you're weighing claims about small modular reactors

Distinguish signed agreements from reactors under construction, and look for firm cost estimates; the IEA says SMRs must become cost-competitive to scale.13

Evidence-backed

If you're tracking US nuclear capacity to 2030

Follow licence renewals rather than new-build announcements: 22 licences expire before the end of 2029 if not renewed, and 41 reactors have already shut permanently.5

Evidence-backed

If you're assessing whether a country's nuclear share can grow

Check whether it is adding new reactors or mainly extending the life of existing ones, since the US case shows a large fleet can still shrink through closures and expiries.51

Interpretation

If you're judging local political risk for a project

Expect public argument to matter: nuclear debate has been long-running and intense, and licence decisions beyond 60 years require public involvement.65

Evidence-backed

The full story · 5 chapters

01

Where things stand

AI summary:Record global nuclear generation and over 70 GW under construction, but cost overruns and delays remain the main obstacle.

Evidence-backed

Evidence-backed: The IEA's 2025 report projected record nuclear generation that year, with more than 70 GW of new capacity under construction worldwide, much of it in China. It identified cost overruns and delays as the main obstacle to further growth.1

Evidence-backed

Evidence-backed: In the US, Vogtle Units 3 and 4 in Georgia entered service in 2023 and 2024, the first new reactors built from scratch in decades, after years of delay and large cost increases.4

Evidence-backed

Evidence-backed: The US fleet is 96 commercial reactors with about 98 GW net capacity (65 pressurised water and 31 boiling water reactors). They produced 771.5 TWh in 2022, and by 2024 nuclear was 18.6% of US electric generation; in 2018 it was nearly 50% of US emission-free generation. The US remains the world's largest producer of commercial nuclear power, though past and scheduled closures mean China and Russia could surpass it.5

02

The AI data-centre effect

AI summary:Microsoft's deal will restart an 835 MW Three Mile Island unit by 2028, and Google aims for a first Kairos SMR by 2030.

Evidence-backed

Evidence-backed: In September 2024, Constellation signed a 20-year deal with Microsoft to restart Three Mile Island Unit 1 as the Crane Clean Energy Center, about 835 MW, expected online in 2028.2

Evidence-backed

Evidence-backed: A month later, Google agreed to buy power from Kairos Power's small modular reactors, aiming for the first unit by 2030 and up to 500 MW by 2035.3

03

The existing fleet: renewals, expiries and closures

AI summary:The US fleet is ageing: 41 reactors shut, 22 licences expiring before 2029, so renewals and restarts decide near-term capacity.

Evidence-backed

Evidence-backed: As of January 2022 the US regulator had granted licence renewals to 94 commercial reactors, and it was preparing for the first applications to operate beyond 60 years, a process that by law requires public involvement.5

Evidence-backed

Evidence-backed: Against that, 41 US reactors have been permanently shut down as of July 2026, and licences for 22 reactors are due to expire before the end of 2029 if no renewals are granted.5

Evidence-backed

Evidence-backed: Public argument about nuclear is long-running and was especially intense in the 1970s and 1980s; it intensified again in the 2010s as climate change rose up the agenda. Proponents argue nuclear is a consistently reliable, low-carbon source that provides large amounts of uninterrupted power, well-paying jobs and energy security, and reduces dependence on imported fuels and exposure to fuel price risks.6

04

Three scenarios to 2035

AI summary:Three paths to 2035: breakthrough, muddle through, or stall, with US fleet data tilting toward the middle.

Interpretation

Interpretation: Breakthrough: first SMRs arrive on time, costs fall with repeat builds, and tech demand finances a wave of orders. Muddle through: restarts and uprates of existing plants add capacity, a handful of first-of-a-kind SMRs come online late, and large new builds remain rare outside China. Stall: first SMR projects overrun like Vogtle, investors retreat, and growth comes mainly from China and extended lifetimes of existing reactors.14

Interpretation

Interpretation: The US fleet data tilt the near-term balance toward the middle scenario: with 22 licences expiring before 2030 and 41 reactors already shut, renewals, restarts and uprates are the levers that decide whether US capacity holds or slips, while new-build growth is more likely to come from China.51

05

Indicators to watch

AI summary:Watch the Crane restart, the first Kairos unit, SMR construction starts and costs, and US licence renewals.

Interpretation

Interpretation: Signals that would move the forecast: whether the Crane restart meets its 2028 target; whether the first Kairos unit is on track for 2030; construction starts (not announcements) for SMRs in North America and Europe; and published costs for completed first-of-a-kind SMRs.231

Interpretation

Interpretation: Also watch how many of the 22 US licences expiring before the end of 2029 are renewed, and whether any of the 41 shut reactors follow the Crane restart path back to service.52

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Sources

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  1. 1
    The Path to a New Era for Nuclear Energy
    International Energy AgencyPublished Jan 16, 2025Checked Sep 30, 2026
    “Nuclear generation is set to reach a record high in 2025. More than 70 GW of new capacity is under construction worldwide, but cost overruns and delays remain a major barrier, and SMRs must become cost-competitive to scale.”
  2. 2
    Constellation to launch Crane Clean Energy Center, restoring jobs and carbon-free power to the grid
    Constellation EnergyPublished Sep 20, 2024Checked Sep 30, 2026
    “A 20-year power purchase agreement with Microsoft will restart Three Mile Island Unit 1, adding approximately 835 megawatts of carbon-free energy. The plant is expected to be online in 2028.”
  3. 3
    Google signs advanced nuclear clean energy agreement with Kairos Power
    GooglePublished Oct 14, 2024Checked Sep 30, 2026
    “The agreement aims to bring Kairos Power's first small modular reactor online by 2030, followed by additional deployments through 2035, for up to 500 MW of new carbon-free power.”
  4. 4
    Plant Vogtle Unit 4 begins commercial operation
    US Energy Information AdministrationPublished May 1, 2024Checked Sep 30, 2026
    “Vogtle Unit 4 in Georgia began commercial operation, following Unit 3 in 2023; they were the first new reactors built from scratch in the US in decades, completed years late and far over budget.”
  5. 5
    Nuclear power in the United States (Wikipedia)
    WikipediaPublished Oct 4, 2026Checked Oct 4, 2026
    “In the United States, nuclear power is provided by 96 commercial reactors with a net capacity of 98 gigawatts (GW), with 65 pressurized water reactors and 31 boiling water reactors. In 2022, they produced a total of 771.5 terawatt-hours of electricity, and by 2024 nuclear energy accounted for 18.6% of the nation's total electric energy generation. In 2018, nuclear comprised nearly 50 percent of US emission-free energy generation. As of July 2026, 41 reactors have been permanently shut down. The United States is the world's largest producer of commercial nuclear power, and in 2013 generated 33% of the world's nuclear electricity. With the past and future scheduled plant closings, China and Russia could surpass the United States in nuclear energy production. As of January 2022, the U.S. Nuclear Regulatory Commission (NRC) had granted license renewals to a total of 94 commercial reactors. In early 2014, the NRC prepared to receive the first applications of license renewal beyond 60 years of reactor life as early as 2017, a process which by law requires public involvement. Licenses for 22 reactors are due to expire before the end of 2029 if no renewals are granted.”
  6. 6
    Nuclear power debate (Wikipedia)
    WikipediaPublished Oct 2, 2026Checked Oct 4, 2026
    “The nuclear power debate is a long-running controversy about the risks and benefits of using nuclear reactors to generate electricity for civilian purposes. The debate about nuclear power peaked during the 1970s and 1980s, as more and more reactors were built and came online, and "reached an intensity unprecedented in the history of technology controversies" in some countries. In the 2010s, with growing public awareness about climate change and the critical role that carbon dioxide and methane emissions plays in causing the heating of the Earth's atmosphere, there was a resurgence in the intensity of the nuclear power debate. Proponents of nuclear energy argue that nuclear power is the only consistently reliable clean and sustainable energy source which provides large amounts of uninterrupted energy without polluting the atmosphere or emitting the carbon emissions that cause global warming. They argue that use of nuclear power provides well-paying jobs, energy security, reduces a dependence on imported fuels and exposure to price risks associated with resource speculation and foreign policy.”

How it changed

Published 4 times since Sep 30, 2026.

  1. Version 4Oct 4, 2026Live now

    Added two new sources on the US reactor fleet and the public debate, which sharpen the picture of where growth can come from (restarts, uprates, licence renewals) and what could slow it (licence expiries, plant closures, contested public support). Kept the existing forecast, scenarios and indicators, and folded the new material into the finding, a new section, uncertainty and takeaways.

    • The main finding was rewritten.
    • Updated “Where things stand”.
    • Added section “The existing fleet: renewals, expiries and closures”.
  2. Version 3Sep 30, 2026

    Added the Big Tech power deals, scenarios for the next decade and indicators to watch.

    • Added section “Three scenarios to 2035”.
    • Added section “Indicators to watch”.
    • Key takeaways were added.
  3. Version 2Sep 30, 2026

    First brief from the IEA's 2025 nuclear outlook and the Vogtle completion.

    • The main finding was rewritten.
    • The finding is now labelled “evidence” (was “interpretation”).
    • Added section “Where things stand”.
  4. Version 1Sep 30, 2026

    Created the Sylo.

    • First published version.
Every version, side by side

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The brief is open about what's uncertain. These are the specific gaps that new material would fill.

  • “Three scenarios to 2035” has no evidence or firsthand experience yet

    It's a synthesis for now. Evidence or experience would show whether it holds.

  • “Indicators to watch” has no evidence or firsthand experience yet

    It's a synthesis for now. Evidence or experience would show whether it holds.

Open questions

  • What are the latest cost estimates for first-of-a-kind SMRs under construction?

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  • Which other closed reactors could realistically be restarted?

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  • How many of the 22 US licences expiring before the end of 2029 will be renewed, and what will replace any that are not?

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  • How has public support for nuclear changed in your country?

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