The 2026 SMR licensing map: who is actually where, from design approval to first power

Ask “who leads in SMRs” and you get three answers: NuScale, the only SMR developer with an NRC design approval; China, which is building the world’s first land-based commercial SMR; or, counting hyperscaler contracts, Oklo and Kairos. None of the three is wrong. They are measured with different rulers.

This article fixes the ruler. The licensing stage a reactor must pass before it can sell electricity is the one measure that, unlike an announcement or a memorandum, is hard to walk back. Our Korean explainer covers what an SMR is (in Korean).

Key takeaways

• Only two SMRs are operating anywhere: Russia’s Akademik Lomonosov and China’s HTR-PM. The West has zero.
• The Western front line is “construction permit granted, concrete poured”: TerraPower’s Natrium, Ontario’s Darlington BWRX-300, and Kairos Hermes.
• Korea’s i-SMR is on the first rung (Standard Design Authorization review under way, filed February 2026). Its 2028 approval target has almost no slack.

1. The ruler first: what a licensing stage guarantees, and what it does not

The ladder has six rungs, from the bottom: design under review → design approved → construction permit → under construction → commissioning → operating. Up to design approval you have a reactor on paper; money and concrete start with the construction permit; operation is a separate gate. The table maps the rungs onto four regulators as of September 2026: the US Nuclear Regulatory Commission (NRC), the Canadian Nuclear Safety Commission (CNSC), the UK Office for Nuclear Regulation (ONR) and Korea’s Nuclear Safety and Security Commission (NSSC).

In the last column, the entry before the slash is the UK, the entry after it is Korea.

United States. Three things matter.

• A construction permit means “you may build,” not “you may run.” On the traditional path (10 CFR Part 50) a CP is granted on a preliminary safety analysis report; the final report is reviewed again for a separate Operating License (OL).
• Design approval is site-independent. Part 52 (issued in 1989) offers Design Certification (DC), which approves a standard design as a formal NRC rule, and Standard Design Approval (SDA), the same technical review closed out by NRC staff without rulemaking. Both are valid for 15 years and only spare the design portion from re-review at a specific site; neither lets anyone build or operate anything. The Combined License (COL) authorizes construction and operation in one step, subject to verifying Inspections, Tests, Analyses and Acceptance Criteria (ITAAC) before startup.
• New routes have opened, one of them outside the NRC. Part 53, effective April 29, 2026, is an optional NRC licensing framework alongside Parts 50 and 52, technology-neutral and risk-informed. Separately, the Department of Energy (DOE) can authorize test and demonstration reactors on its own sites or under its own contracts; that is not a commercial license, and selling power to the grid still requires the NRC. Executive Order 14300 of May 23, 2025 directed the NRC to decide new reactor applications within 18 months and to overhaul its rules.

Canada and the UK. Pre-reviews and actual licenses need separating.

• The CNSC’s Vendor Design Review is a three-phase pre-licensing service; the regulator itself states that it is not a license and does not bind the Commission. Actual licensing runs Licence to Prepare Site → Licence to Construct → Licence to Operate, each with public hearings.
• The UK’s Generic Design Assessment (GDA) runs step 1 (initiation), step 2 (fundamental assessment) and step 3 (detailed assessment). Completing step 3 yields a Design Acceptance Confirmation (DAC) from ONR and a Statement of Design Acceptability (SoDA) from the Environment Agency. Neither is a statutory license; the site license and consent to construct come separately.

China and Russia. The National Nuclear Safety Administration and Rostechnadzor issue the licenses, and the operator is a single state company (CNNC/CGN, Rosatom), so design, construction, operation and regulatory engagement sit inside a single state structure.

Korea. Under the Nuclear Safety Act, the NSSC issues Standard Design Authorization → Construction Permit → Operating License, with the Korea Institute of Nuclear Safety (KINS, its technical review body) doing the review. Standard Design Authorization pre-certifies a design meant to be built repeatedly (Korean agencies often translate it “Standard Design Approval” too), and is the counterpart of the US SDA.

2. Project by project: the current rung (early September 2026)

Rungs ⑥ and ⑤: operating, commissioning, late construction

Rungs ④ and ③: under construction, construction permit under review

Rungs ② and ①: design approved, design under review

3. Who leads: three yardsticks

Yardstick 1, operating record: China and Russia

In September 2026, the number of SMRs selling electricity in the West is still zero. But both countries’ first units are either icebreaker reactors moved ashore (KLT-40S, RITM-200) or an extension of a state research program (HTR-PM), with operator, regulator and money inside a single state structure, so the first-of-a-kind cost question never arose. Even so, Linglong One has not reached criticality five years after construction began in 2021, and a unified system does not make a first SMR easy.

Yardstick 2, Western regulatory passage: United States and Canada

Three projects hold construction permits and have poured nuclear concrete: Natrium, Darlington BWRX-300 and Kairos Hermes. Darlington is the first of them in operating-license review, for two reasons.

• BWRX-300 had completed CNSC Vendor Design Review phases 1 and 2, shrinking the issues to reopen at the construction-license stage.
• The buyer is Ontario’s public utility, so the power always had a taker.

The NuScale–UAMPS project (a Utah municipal-utility consortium) was canceled in November 2023 on rising costs and too few utilities subscribing; a first unit gets none of the benefits of serial production; and regulators had limited review staff.

What changed in 2026 is speed: the 18-month deadline in Executive Order 14300, Part 53 taking effect, the Clinch River safety evaluation landing five months early, and the Xe-100 environmental review closing under a streamlined procedure. Faster review does not, however, lower the cost of the first unit.

Yardstick 3, commercial contracts: US developers tied to hyperscalers

Google–Kairos 500 MW by 2035, Amazon–X-energy 5 GW by 2039, Meta–Oklo 1.2 GW and Meta–TerraPower up to eight units (January 2026) are the headline deals. Not one of these reactors has been licensed to operate, and most of the power dates fall after 2030. A contract is evidence of demand, not of a reactor.

4. Korea on the same ruler

Korea’s position is the first rung. As covered in our i-SMR status report, the i-SMR (4 × 170 MWe, total program budget KRW 399.2 billion, about $295 million) filed for Standard Design Authorization on February 27, 2026 and is at the start of review.

• The KINS review plan reported on August 27 lists 13 supplementary items and sets test-result submission for June 2028, leaving almost no slack against the “approval in 2028” target.
• Gijang County was confirmed as the candidate site in June; the plan is construction in 2030 and operation in 2035.
• The SMR Special Act passed the National Assembly on February 12, 2026 and takes effect on September 11, 2026. The NSSC’s “SMR regulatory framework roadmap (2026–2030)” puts SMR-specific technical standards and the associated law amendments in 2028. Review and rule-writing run in parallel; Korean environmental groups argue that “licensing has started while the regulatory framework is still being built” and want the standards first.
• At a September 1 forum on private-sector SMR development, GS Energy, SK Innovation and POSCO Holdings presented participation plans, but what they asked for was permission for long-term power purchase agreements and inclusion in the 12th Basic Plan for Electricity Supply and Demand.

Korea already holds some pieces.

• SMART100, Korea’s second SMR standard design, received Standard Design Authorization in September 2024; KAERI (Korea Atomic Energy Research Institute), KHNP (Korea Hydro & Nuclear Power, the state utility that runs all Korean reactors) and Saudi Arabia’s KA-CARE are pursuing a Saudi build.
• KAERI has developed high-temperature gas reactor technology for hydrogen since 2004 and partnered with POSCO E&C on an indigenous design, and its molten-salt reactor concept for ships was reported to have received approval in principle from the American Bureau of Shipping in July 2026.
• Doosan Enerbility (Korea’s reactor-vessel manufacturer) supplies NuScale’s main components and reserved forgings for 16 Xe-100 units with X-energy (December 2025); Hyundai E&C, Samsung C&T and Daewoo E&C are tied to Holtec Palisades, NuScale Romania and the i-SMR respectively.

Weighing strengths and weaknesses equally. The strength is a manufacturing supply chain that has actually produced large-reactor main components, the position that receives work first as Western SMRs move into construction. The weaknesses are three: nobody has been assigned the first-of-a-kind cost, no buyer for the electricity exists yet, and the regulator’s review staff and standards must keep pace with the project.

Spent fuel does not disappear because the reactor got smaller; see our Korean piece on waste volume (in Korean).

5. Technology branches: light water first, fuel decides the rest

Light-water reactors dominate the ladder from top to bottom: NuScale, BWRX-300, i-SMR, AP300, Rolls-Royce, Linglong One. (Designs above 300 MWe, like the 470 MWe Rolls-Royce unit, are still called SMRs in the industry.) Regulators have reviewed the technology for 60 years, so criteria, interpretations and staff exist, and the fuel is the same below-5-percent uranium, so a supply chain exists; Korea chose an integral LWR for the i-SMR on the same calculation.

Natrium (sodium fast reactor), Xe-100 (high-temperature gas), Kairos (fluoride-salt-cooled) and Oklo (fast reactor) mostly use HALEU, high-assay low-enriched uranium enriched to 5–20 percent uranium-235, just under the 20 percent HEU threshold (weapons-grade is around 90 percent) and chosen to run fuel longer in a smaller core.

Only one Western company is producing at this assay today: Centrus, which runs the only US facility licensed to enrich up to 19.75 percent, in Piketon, Ohio. By June 2026 it had filled its entire pilot contract, delivering more than 1,900 kg to DOE; in July 2026 it moved toward commercial production under a $900 million DOE contract, but its initial commercial plant is targeted for 2029, with 12 metric tons per year after that. A pilot output of about 900 kg per year is small against several commercial-scale reactors, so the non-LWR schedules depend on fuel as much as on licensing.

Where this goes next

Watch three things through the end of 2026: whether the NRC issues the Clinch River CP after the August hearing, whether Rolls-Royce SMR receives its DAC, and whether Linglong One loads fuel. In Korea, the KINS supplementary-item schedule and the 2028 rule-writing target will show whether the i-SMR’s 2028 date is a plan or a hope.

Industry note

On the ladder, revenue arrives first on the upper rungs. Doosan Enerbility (KRX: 034020) makes main components and forgings for permitted US and Canadian projects, Hyundai E&C (KRX: 000720) is Holtec’s EPC partner at Palisades, and Centrus (NYSE: LEU) produces HALEU; NuScale (NYSE: SMR) and Oklo (NYSE: OKLO), still on the design and DOE rungs, move most on approval news. The full value chain is in our Korean guide to SMR and nuclear stocks (in Korean).

This section is provided to help understand the industry and is not a recommendation to buy or sell any security. Investment decisions and their consequences are the reader’s own.

Sources: US NRC releases and project pages (NuScale US460 SDA, 2025; Natrium CP and Part 53 final rule, 2026; Clinch River, Long Mott, Palisades dockets); US DOE Reactor Pilot Program (2025, 2026); Executive Order 14300 (2025); CNSC Darlington project page, REGDOC-3.5.4; UK ONR GDA guidance; World Nuclear News (Aug 3, 2026 Linglong One; Darlington operating-license application; Oklo, 2026); ANS Nuclear Newswire (Holtec, Clinch River, Kairos, Centrus, 2026); Nuclear Engineering International (CAREM, 2024; Yakutia); Argentine press (CNEA cuts, 2026); Kairos Power, TerraPower, Oklo, Centrus, Dow, Vattenfall releases; NSSC/KINS i-SMR review plan and SMR regulatory roadmap (2026); KAERI SMART100 release (2024); Doosan Enerbility release (2025)