Key takeaways
- Three SMR systems are in commercial operation: the Akademik Lomonosov floating plant and RITM-200 icebreaker reactors in Russia, and the HTR-PM in China. Several Western projects are under construction.
- Google, Meta and Amazon have signed deals with SMR developers, while Microsoft’s 20-year PPA covers the restart of Three Mile Island Unit 1, an existing plant rather than a new SMR.
- The main bottleneck is fuel: many advanced reactor designs need HALEU, and Russia was historically the only commercial HALEU supplier.
Small modular reactors are nuclear plants designed to be built in factory modules rather than as one-off site builds. They have been discussed for years, and in 2026 they are starting to move from promises to concrete projects. A handful of reactors are generating power commercially, and several more are under construction. The UK, Canada, South Korea and France are expanding nuclear commitments.
Whether they will deliver on that promise — at a price, on a schedule, and at a scale that makes a meaningful contribution to the global energy mix — remains contested. The gap between a first-of-kind demonstration plant and a commercially competitive technology is wide, and earlier efforts, most notably NuScale’s cancelled Idaho project in 2023, illustrated how difficult it is to close. But the landscape in late 2026 looks meaningfully different from two years ago, with more projects in the ground and more technology companies willing to sign power purchase agreements.
What SMRs Are and Why the Name Is Used Loosely
The term describes a design approach: components are built in a factory and assembled on site, rather than a custom plant built from scratch. SMR Intel says the economics depend on modular factory construction rather than bespoke site builds, targeting NOAK cost reductions of 30-50%.
In practice, the term covers a wide range of technologies. Some use the pressurised water design that dominates conventional nuclear power. Others use novel coolants, such as molten salt, liquid sodium or helium gas. The sources describe six major reactor types, each with different coolants, fuels, safety profiles, and deployment timelines. Grouping them all as SMRs makes the technology sound more uniform than it is.
SMRs in Numbers
Three SMR systems are listed in commercial operation as of July 2026: Russia’s Akademik Lomonosov (70 MWe), China’s HTR-PM (210 MWe) and Russia’s RITM-200 icebreaker reactors. China’s Linglong One (125 MWe) was targeted for commercial operation in H1 2026, and that had not been confirmed in the sources used. The BWRX-300 at Darlington targets 2029 to 2030. The US Department of Energy announced more than $94 million in cost-share funding for light water SMR deployment in May 2026. SMR Intel’s tracker covers six major reactor types.
What Is Actually Running Today
The only commercially operating SMR systems in 2026 are Russian and Chinese, according to SMR Intel’s July 2026 update. Russia’s Akademik Lomonosov, a floating nuclear power plant at Pevek, has been operational since 2020 and has an electrical output of 70 MWe. Russia also operates RITM-200 reactors powering multiple icebreakers.
In China, the HTR-PM high-temperature gas-cooled reactor at Shidaowan has operated commercially since 2023, with an electrical output of 210 MWe. China’s Linglong One, a 125 MWe PWR in Hainan, was listed as testing, with commercial operation targeted for H1 2026. Commercial operation had not been confirmed in the sources used for this article.
What Is Under Construction in the West
The BWRX-300, a 300-megawatt boiling water reactor design derived from GE-Hitachi’s ESBWR, is under construction at Ontario Power Generation’s Darlington site in Canada. The project has the most advanced active construction in North America. Canada’s nuclear regulator, the CNSC, granted a licence to construct in April 2025, and the project targets 2029 to 2030 for commercial operation.
In the United States, TerraPower’s Natrium reactor, a 345 MWe sodium-cooled fast reactor, is under construction at Kemmerer, Wyoming, with a target of 2030. TerraPower, the Bill Gates-backed company founded in 2008, received its NRC construction permit in March 2026. Meta has announced a deal with TerraPower for eight Natrium plants.
Oklo, which broke ground on its Aurora reactor at Idaho National Laboratory, has a 1.2 GW deal with Meta for an Aurora campus in Pike County, Ohio. Kairos Power holds an NRC construction permit, issued in December 2023, for its Hermes demonstration reactor at Oak Ridge, Tennessee, which is targeted for 2027 to 2028. Google has a 500 MW deal with Kairos.
Big Tech as the Buyer
Data centres running large-scale AI workloads consume large amounts of electricity. Hyperscalers building out frontier-AI training and inference capacity have run into the limits of where the existing grid can deliver multi-hundred-megawatt loads on short timelines. Nuclear offers 24/7 carbon-free baseload with 90%+ capacity factors, positioning SMRs as critical grid infrastructure.
Google, Meta and Amazon have all signed deals with SMR developers. Amazon has a 960 MW deal with X-energy for up to 12 Xe-100 reactors. Microsoft’s deal is different: a 20-year power purchase agreement (PPA) for the 835 MW output of the Three Mile Island Unit 1 restart, which had been shut in 2019.
Utility off-takers are unwilling to bear the cost-overrun risk alone. The hyperscaler PPAs are now the most credible commercial path for SMR companies to get first-of-a-kind projects funded and built.
The hyperscaler PPAs are now the most credible commercial path for SMR companies to get first-of-a-kind projects funded and built.
The Fuel Bottleneck
Many advanced reactor designs need high-assay low-enriched uranium, or HALEU, which is enriched to between 5% and 20% U-235, compared with standard LEU at 3-5%. Designs that need it include TerraPower’s Natrium, X-energy’s Xe-100, Oklo’s Aurora, Kairos Hermes and Radiant Kaleidos. Russia was historically the only commercial HALEU supplier. Centrus Energy is the only US HALEU producer, with a 16-centrifuge demonstration cascade producing about 900 kg/year, far below the multi-ton demand from planned reactors.
In May 2026, the Department of Energy announced that eight companies will collectively receive more than $94 million in cost-share funding to expedite the near-term deployment of small light water modular reactors.
What the Timeline Realistically Looks Like
If current projects proceed on schedule, the BWRX-300 at Darlington targets 2029 to 2030, and TerraPower’s Natrium in Wyoming is aiming for 2030. Rolls-Royce’s SMR for Wylfa in Wales has a target of 2031. The UK Generic Design Assessment Step 3 for that design was expected to complete in August 2026. NuScale’s planned 462 MWe project in Romania targets 2030 and beyond.
Several projects are still in regulatory review and may face delays. Holtec’s SMR-300 construction permit application, filed in December 2025, is under review. The wider lesson from NuScale’s cancellation, as the industry has absorbed it, is that first-of-a-kind nuclear builds are expensive in unpredictable ways.
Sources
- State of SMR 2026, SMR Intel
- DOE selects companies for $94M in light water SMR deployment awards, American Nuclear Society
- Nuclear SMRs in 2026: NuScale Lessons, TerraPower Wyoming, and the AI Datacentre PPAs, PDP Spectra
- Which Advanced Nuclear Models Are Likely to Hit Emerging Markets First?, Energy for Growth Hub
