SMR construction permits and licences
19 companies have moved past design review to building or applying to build. 8 hold a construction permit or run a plant, led by the BWRX-300 at Darlington and Clinch River↗++ TerraPower’s Natrium at Kemmerer↗+ and X-energy’s Xe-100s at Dow’s Long Mott site↗+. 5 are grouped under DOE pilot or test activities, and 6 have a construction, site or creation application before a regulator.
| Regulators | First site | ||||||
|---|---|---|---|---|---|---|---|
| X-energy | Construction licensed | 2026-11-09 | NRC | Xe-100 | Long Mott, Seadrift, Texas (Dow): four Xe-100s | — | 2026-11-11 |
| Radiant Industries | DOE test authorization | 2026-10-29 | DOE; NRC | Kaleidos | DOME test bed, Idaho National Laboratory | 2,0261 | 2026-11-11 |
| GE Vernova Hitachi Nuclear Energy | Construction licensed | 2026-09-29 | CNSC; NRC | BWRX-300 | Darlington, Ontario (OPG): four units planned, Unit 1 under construction | — | 2026-11-11 |
| Jimmy Energy | Construction under review | 2026-07-23 | ASNR | Jimmy high-temperature heat generator (INB Fermi) | Bazancourt (Marne), supplying heat to Cristal Union’s industrial facility | — | 2026-11-11 |
| Aalo Atomics | DOE test authorization | 2026-07-04 | DOE | Aalo-X; Aalo-1; Aalo Pod | Idaho National Laboratory (Aalo-X, with a co-located experimental data center planned) | 2,0284 | 2026-11-11 |
| Antares Nuclear | DOE test authorization | 2026-06-04 | DOE | Mark-0 (test); R1 | Idaho National Laboratory (Mark-0); military installations from 2028 | 2,0273 | 2026-11-11 |
| NANO Nuclear Energy | Construction under review | 2026-05-18 | NRC | KRONOS MMR | University of Illinois Urbana-Champaign campus | — | 2026-11-11 |
| TerraPower | Construction licensed | 2026-03-09 | NRC | Natrium | Kemmerer, Wyoming (Kemmerer Unit 1), next to a retiring coal plant | 2,0302 | 2026-11-11 |
| Holtec International | Construction under review | 2026-02-13 | NRC | SMR-300 | Pioneer Units 1 and 2, Palisades Energy Center, Michigan (two proposed units of approximately 340 MWe each) | — | 2026-11-11 |
| Stellaria | Construction under review | 2025-12-19 | ASNR | Stellarium; Alpha/Alvin experimental reactor | CEA Cadarache (experimental reactor); commercial Stellarium deployments from 2035 | 2,0352 | 2026-11-11 |
| Kairos Power | Construction licensed | 2024-11-21 | NRC | KP-FHR; Hermes; Hermes 2 | Hermes 2, Oak Ridge, Tennessee: 50 MWe sold to TVA | 2,0304 | 2026-11-11 |
| Natura Resources | Construction licensed | 2024-09-16 | NRC | MSR-1; MSR-100 | Abilene Christian University, Abilene, Texas (MSR-1); Texas A&M RELLIS (MSR-100) | — | 2026-11-11 |
| China Huaneng (HTR-PM) | Operating | 2023-12-06 | NNSA (China) | HTR-PM (two reactors, one 210 MWe turbine) | Shidaowan (Shidao Bay), Shandong | 2,0232 | 2026-11-11 |
| ARC Clean Technology | Construction under review | 2023-06-30 | CNSC | ARC-100 | Point Lepreau, New Brunswick (NB Power) | — | 2026-11-11 |
| Rosatom | Construction licensed | 2023-04-21 | Rostekhnadzor | RITM-200N | Ust-Kuyga, Yakutia (Sakha Republic) | 2,0281 | 2026-11-11 |
| CNNC (China National Nuclear Corporation) | Construction licensed | 2021-07-01 | NNSA (China) | ACP100 (Linglong One) | Changjiang nuclear power plant, Hainan | — | 2026-11-11 |
| Blykalla | Construction under review | — | SSM; Swedish Government | SEALER-55; SEALER-One prototype | Oskarshamn: non-nuclear electric pilot facility with Uniper (ground broken February 2025) | — | 2026-11-11 |
| Last Energy | DOE test authorization | — | DOE | PWR-20; PWR-5 pilot | Texas A&M RELLIS campus, Bryan, Texas (PWR-5 pilot); Haskell County, Texas (30 PWR-20s, ERCOT connection requested) | 2,0261 | 2026-11-11 |
| Valar Atomics | DOE test authorization | — | DOE | Ward 250 | Utah San Rafael Energy Lab, near Orangeville, Utah | 2,0261 | 2026-11-11 |
How to read the licensing stage
How the data is sourcedA permit to build is not a licence to operate
An NRC construction permit authorizes construction, with operation requiring a separate approval. TerraPower’s NRC schedule records its construction-permit decision on 9 March 2026↗+. Canada’s CNSC licensed OPG to build one BWRX-300 at Darlington. OPG’s November 2026 update withdrew the earlier October 2030 operation target↗++.
DOE test reactors run on a separate track
The DOE Reactor Pilot Program authorizes test reactors outside NRC licensing. Antares went critical first, on 4 June 2026↗, followed by Valar Atomics and Aalo Atomics↗. Pilot-program selection, safety-analysis approval, criticality and permission to operate are separate milestones; the licensing detail states which one has been reported.
Applications on file
Holtec has filed both parts of its application for two SMR-300s at Palisades↗+, and the University of Illinois filed for NANO Nuclear’s KRONOS↗. In France, Jimmy Energy and Stellaria have creation applications before ASNR.