TerraPower Successfully Navigates The NRC Permitting Process

On March 4, 2026, the U.S. Nuclear Regulatory Commission ("NRC" or the "Commission") unanimously voted to issue a construction permit to a subsidiary of TerraPower, LLC ("TerraPower"), authorizing the company to construct the Natrium reactor project in Kemmerer, Wyoming (see the NRC press release here). The 345-megawatt ("MW") reactor will utilize a liquid-sodium passive cooling system, a paired liquid-sodium energy storage facility, advanced fuel, and a simplified design—all of which distinguish it from the conventional fission reactors that constitute the legacy U.S. nuclear power fleet. Construction of the facility has already begun, and TerraPower expects the plant to be ready to commence commercial operational by 2030. To begin generating power, TerraPower will need to obtain a Class 103 operating license pursuant to 10 C.F.R. Part 50.

The permit issuance sends a number of useful signals for all those tracking development of nuclear power in the United States:

The NRC has proven that it can permit technological innovation at grid scale, with speed, and under existing regulations. TerraPower now holds the first permit issued under the NRC's construction regulations (which, like the regulations governing operating licenses, are housed at 10 C.F.R. Part 50) to a non-light-water, commercial-scale reactor (or, in plainer English, to a nuclear facility that (i) utilizes safety and cooling technologies more advanced than those used by the legacy American nuclear fleet and (ii) will contribute substantially to serving load, rather than acting as technological proof-of-concept) since the 1970s. This is despite the fact that final regulations under the Accelerating Deployment of Versatile, Advanced Nuclear for Clean Energy Act of 2024 (the "ADVANCE Act"), which will aim to accelerate permitting of both advanced fission and fusion reactors, have yet to be promulgated.

Accordingly, the Natrium permit issuance bodes favorably for other projects in the NRC permitting pipeline currently seeking permits under 10 C.F.R. Part 50 (i.e., before the ADVANCE Act regulations come into effect), including the Tennessee Valley Authority Clinch River 300-MW advanced reactor to be sited in Tennessee and the X-energy Long Mott 320-MW project under development in Texas.

The TerraPower experience offers a blueprint for developers seeking accelerated NRC review. The NRC credited TerraPower's "frequent and productive engagements" with NRC staff before submitting its permit application, and while the application was under review, as one reason that the application could be processed unusually quickly. Importantly, TerraPower also initially submitted a high-quality and thorough application that did not require revision after filing (the application was filed in March 2024 and accepted shortly thereafter in May 2024. (Per TerraPower CEO Christopher Levesque, "[w]hen [TerraPower] submitted [its] 14,000-page application in March 2024, that was the culmination of years of pre-application engagement" and "multiple training sessions with the NRC and Wyoming regulators.") Certain design elements also accelerated NRC processing, namely the architectural separation of the facility's electric-generating mechanisms from the nuclear reactor itself and incorporated safety systems. This "islanding" of the nuclear and generating facilities reduced the size and complexity of the nuclear facility itself and allowed the NRC essentially to confine its safety review to the reactor components.

A "whole of government" approach to developing new nuclear power is finally bearing fruit. The NRC processed TerraPower's permit application in a record eighteen months—nine months ahead of its own projections— in what appears to be the successful culmination of years of effort by Congress, the executive branch, and industry to accelerate the deployment of new nuclear capacity. While the NRC's speed in this instance is noteworthy, the permit issuance is perhaps better understood in the context of the multiple federal actions, spanning six years and three executive administrations, that together produced a construction permit for a grid-scale Generation IV advanced nuclear reactor. These include the Nuclear Energy Innovation and Modernization Act of 2019 ("NEIMA"), passed by a Republican-led Senate and signed by President Trump; the Energy Act of 2020, which authorized the U.S. Department of Energy Advanced Reactor Demonstration Program, through which TerraPower's Natrium project was selected for public-private cost sharing in 2020 and through which it will receive as much as $2 billion in federal funding; the NRC's 2020 approval of a "risk-informed, performance-based review process" proposed by industry stakeholders for non-light water reactors (and on which TerraPower relied in its permit application); the ADVANCE Act of 2024, passed by a Democrat-led Senate and signed by President Biden, aimed at accelerating permitting; and President Trump's four May 2025 Executive Orders, which target speeding deployment, expediting reactor testing, and rebuilding the nuclear fuel supply chain.

While navigating permit application review at the NRC will remain anything but simple—especially while the industry awaits promulgation of the final ADVANCE Act regulations later in 2026—the TerraPower permit issuance shows that NRC permitting processes are becoming substantially more efficient, even more so where permit applicants enable NRC staff to confine the scope of their review through thoughtful system design and to engage directly with the developer.

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