Small modular reactor developers moved closer to building their first US units in 2026, with several projects clearing key regulatory and construction milestones. NuScale Power remains the only company with full Nuclear Regulatory Commission design approval, having secured certification for its 50-megawatt module in January 2023 and standard design approval for its uprated 77-megawatt US460 design in May 2025.
TerraPower stands as the most advanced non-light-water entrant. Its Natrium sodium fast reactor has a construction permit application under active NRC review. The commission completed its environmental review in October 2025 and issued a final safety evaluation in December 2025, with a decision on the construction permit expected in the first half of 2026.
Other developers are already building. Kairos Power received construction permits under the NRC's Part 50 process to build two test reactor facilities in Tennessee, though it will still need operating licenses before those reactors can run. Oklo broke ground at Idaho National Laboratory in September 2025 for its Aurora reactor.
The activity reflects growing interest in factory-built reactors as a source of firm power for utilities and large electricity buyers, including technology companies seeking reliable supply for data centers. Developers still face a multi-step licensing path, and even projects with construction permits must obtain separate operating licenses before generating power.
As of 2026, NuScale, TerraPower, and Kairos Power represent the most advanced NRC engagement in a field of dozens of SMR companies competing to reach commercial operation.
Source: American Bar Association - https://www.americanbar.org/groups/environment_energy_resources/resources/trends/2026-mar-apr/pressure-to-succeed-small-modular-nuclear/