Which Countries Are Building SMRs?
As of May 2026, at least 13 countries are actively building, licensing, or operating small modular reactors. China and Russia lead with operational units — China's HTR-PM at Shidao Bay has been grid-connected since 2023, and Russia's Akademik Lomonosov floating plant has operated since 2020. The United States, Canada, and Argentina have SMR units under construction. The UK selected its preferred SMR bidder in April 2026, with commercial operation targeted for 2031-2032. Sweden approved two SMR projects under its new nuclear framework in March 2026. South Korea, France, Poland, Romania, Japan, and India are at various stages from design certification to site selection. Over 80 SMR designs are tracked by the IAEA globally, with projections of 50–80 units operational or under construction by 2035.
ALL COUNTRIES BUILDING SMRS
| COUNTRY | SMR DESIGNS | LEAD PROGRAM | STATUS | TARGET ONLINE | REGULATOR |
|---|---|---|---|---|---|
| 🇺🇸United States | TerraPower Natrium, Kairos Hermes, NuScale VOYGR, X-energy Xe-100, GE-Hitachi BWRX-300 | TerraPower Natrium (Kemmerer, WY) | Under construction | 2027–2030 | NRC |
| 🇨🇦Canada | GE-Hitachi BWRX-300, ARC-100, Moltex SSR-W | BWRX-300 at Darlington (OPG) | Under construction | 2030 | CNSC |
| 🇬🇧United Kingdom | Rolls-Royce SMR (preferred bidder), GE-Hitachi BWRX-300, Holtec SMR-300 | Rolls-Royce SMR (preferred bidder selected Apr 2026) | Preferred bidder selected, GDA pending | 2031-2032 | ONR |
| 🇨🇳China | HTR-PM, Linglong One (ACP100) | HTR-PM (Shidao Bay) | Operational | 2023 (operational) | NNSA |
| 🇷🇺Russia | RITM-200, SHELF-M | Akademik Lomonosov FNPP | Operational | 2020 (operational) | Rostechnadzor |
| 🇦🇷Argentina | CAREM-25 | CAREM-25 (Lima) | Under construction | 2027–2028 | ARN |
| 🇰🇷South Korea | i-SMR, SMART | i-SMR | Design certification | 2030s | NSSC |
| 🇫🇷France | Nuward SMR | Nuward (EDF) | Design phase | 2030s | ASN |
| 🇯🇵Japan | BWRX-300 (GE-Hitachi) | Various | Considering | 2030s | NRA |
| 🇵🇱Poland | BWRX-300, NuScale | BWRX-300 (ORLEN) | Site selected | 2030s | PAA |
| 🇷🇴Romania | NuScale VOYGR | Doicești | Under development | 2030s | CNCAN |
| 🇮🇳India | PHWR-220 (indigenous), AHWR | PHWR fleet | Operational (PHWR) | Ongoing | AERB |
| 🇸🇪Sweden | Blykalla SEALER-55 (LFR), Kärnfull Next SMR | Blykalla SEALER-55 (Norrsundet SMR park) | Site confirmed, permitting in progress | Early 2030s | SSM |
COUNTRIES WITH OPERATIONAL SMRs
Only three countries have SMR-class reactors in commercial operation as of 2026. China's HTR-PM represents the most advanced commercial deployment — a 210 MWe high-temperature gas-cooled reactor at Shidao Bay. Russia operates the Akademik Lomonosov, a floating nuclear power plant with two 35 MWe RITM-200-class reactors serving the remote port of Pevek. India operates a fleet of small PHWR-220 pressurized heavy water reactors, which predate the modern SMR category but fall within the IAEA's sub-300 MWe definition.
HTR-PM, Linglong One (ACP100)
RITM-200, SHELF-M
PHWR-220 (indigenous), AHWR
SMRs UNDER CONSTRUCTION
Three countries currently have SMR units actively under construction. The United States leads with multiple projects: TerraPower Natrium in Kemmerer, Wyoming received its NRC construction permit in March 2026 (the first CP for a commercial non-light-water reactor), and Kairos Power's Hermes test reactor is under construction at Oak Ridge, Tennessee with nuclear concrete poured in May 2025 and a 2027 operational target. NuScale's original CFPP Idaho project was cancelled in 2023 due to cost overruns. Canada's Ontario Power Generation is building the BWRX-300 at the Darlington site, with construction underway since May 2025 and an operating license application submitted in March 2026, targeting 2030. OPG has contracted for 4 BWRX-300 units total. Argentina's CAREM-25, a domestically designed 32 MWe integral PWR, has been under construction at Lima, Buenos Aires Province, with a 2027–2028 target.
TerraPower Natrium, Kairos Hermes, NuScale VOYGR, X-energy Xe-100, GE-Hitachi BWRX-300
GE-Hitachi BWRX-300, ARC-100, Moltex SSR-W
CAREM-25
REGIONAL SMR DEPLOYMENT SUMMARY
| REGION | COUNTRIES ACTIVE | DESIGNS UNDER REVIEW | FURTHEST ALONG | EST. CAPACITY BY 2035 |
|---|---|---|---|---|
| North America | US, Canada | 8+ | Kairos Hermes (US, 2027-28) | 5–8 GWe |
| Asia-Pacific | China, S. Korea, Japan, India | 5+ | HTR-PM (China, operational) | 3–5 GWe |
| Europe | UK, France, Poland, Romania, Sweden | 5+ | Rolls-Royce SMR (UK, preferred bidder selected 2026) | 3–5 GWe |
| Russia / CIS | Russia | 2+ | FNPP (operational) | 1–2 GWe |
| Latin America | Argentina | 1 | CAREM-25 (2027–2028) | 0.1 GWe |
BOTTOM LINE
The global SMR landscape is no longer theoretical. China and Russia have proven that small reactors can reach commercial operation, while the US, Canada, and Argentina are now in active construction phases. The next wave of deployments — expected between 2029 and 2035 — will determine whether SMRs can scale beyond first-of-a-kind projects into serial production. North America leads on design diversity with 8+ reactor concepts in various review stages. Asia-Pacific has the operational advantage. Europe is moving more cautiously but has committed significant policy backing, particularly in the UK and Poland. The key bottleneck across all regions remains the same: regulatory timelines and construction cost control will determine which countries move from plans to operating reactors.