Fusion Update: NRC Publishes Proposed Regulatory Framework For Fusion Machines

We previously commented on the Nuclear Regulatory Commission’s (the “NRC’s”) ongoing efforts to develop a regulatory framework for commercial fusion energy. The proposed rules have arrived. On February 26, 2026, the NRC published the “Regulatory Framework for Fusion Machines” in the Federal Register, opening a 90-day public comment period that closes on May 27, 2026. 

As discussed in our prior post, the NRC had already made an important basic policy choice before issuing this proposal. In 2023, the agency opted to regulate fusion machines under its byproduct material framework. Congress reinforced that approach in the ADVANCE Act of 2024. Broadly, the byproduct material framework is the NRC’s licensing system for the possession and use of radioactive material outside of nuclear power plants. It is the framework the agency uses for a range of medical, industrial, and research activities that involve radioactive material. It focuses on radiation protection, material control, worker training, recordkeeping, inspections, and decommissioning— not the reactor-specific construction and operating requirements that apply to fission facilities. For fusion developers, that means the NRC is proposing to regulate fusion-related radioactive material through a materials-license structure tailored to the technology and would not treat a fusion facility like a traditional nuclear power reactor. 

Fusion differs from fission in ways that shape regulatory decisions. Fission reactors generate energy by splitting atoms such as uranium in a self-sustaining chain reaction. Fusion, on the other hand, combines atoms, typically hydrogen isotopes, at extremely high temperatures to release energy. The same process powers the sun. Fusion machines do not rely on a self-sustaining chain reaction or fissile material, and risks from near-term machines present substantially lower safety concerns than traditional fission reactors. If the conditions necessary for a fusion reaction are lost, the reaction simply stops: There is no risk of a meltdown. The NRC has sought to calibrate the proposed regulations to that lower-risk profile. 

Understanding the Proposed Rule

The proposal would add a fusion-specific pathway within the byproduct material framework (10 C.F.R. Part 30). The NRC describes the rule as “technology-inclusive.” The rule accommodates the wide variety of fusion machine designs under development in the United States, including specific design types like tokamak, stellarator, z-pinch, and field-reverse configurations. According to the NRC, there are currently twenty nine fusion companies based in the United States, several of which are constructing proof-of-concept facilities.

The rule takes a risk-informed, performance-based approach. Rather than prescribing specific design requirements, it sets safety standards such as dose limits (regulatory caps on radiation exposure to workers and the public). Further, applicants for a fusion machine materials license would have flexibility in how they design and operate their machines to meet those standards. Under the proposed § 30.32(k), license applicants would need to provide a description of the machine, radiation safety procedures, operating and emergency protocols, training programs, and methodologies for tracking radioactive material inventories.

The rule would also require applicants to submit an environmental report under 10 C.F.R. Part 51, which sets out the “environmental protection regulations applicable to NRC's domestic licensing and related regulatory functions.” A Part 51 environmental report must “contain a description of the proposed action, a statement of its purposes, a description of the environment affected, and discuss” five specific considerations like the adverse environmental effects which cannot be avoided. 10 C.F.R. Part 51.45. Moreover, the NRC proposes NEPA review of fusion applications to progress through the shorter environmental assessment process rather than using a default full NEPA Section 102(2)(C) environmental impact statement. This proposed decision further reflects the agency’s view that these facilities will generally not have a significant environmental impact.

The proposed rule also establishes a disposal pathway for fusion machine waste at existing low-level radioactive waste disposal facilities and addresses recordkeeping and inspection requirements tailored to the production of tritium and activation products. The NRC acknowledges an important limitation in the current framework. The NRC developed the existing 10 C.F.R. Part 61 waste classification tables in the early 1980s, and the agency recognizes that near-term fusion machines could generate activation products beyond what those tables cover. Because of that uncertainty, the NRC is proposing an interim approach. Fusion waste would either need to fit within an existing waste-class description or go to a disposal site that has completed a site-specific intrusion assessment. The rule gives fusion developers a disposal path, but waste classification and disposal access are still likely to be important implementation issues as commercial designs mature.

Considering Who Will Regulate Fusion Facilities

The NRC will not necessarily be the day-to-day licensing authority for every commercial fusion project. Under Section 274 of the Atomic Energy Act, the NRC may enter into agreements with states allowing them to assume regulatory authority over byproduct material, source material, and small quantities of special nuclear material. These “Agreement States” license and inspect many radioactive-material activities under state law rather than through direct NRC licenses. As of February 2026, there are thirty nine Agreement States. The proposed rule notes that thirty eight of those thirty nine have assumed authority over 11e.(3) byproduct material — the category that would include radioactive material produced by fusion machines.

In practical terms, state radiation control programs, rather than the NRC, are likely to license many future fusion facilities. The NRC emphasized in the proposal that one reason for this rulemaking is to align fusion-related licensing across both the NRC and Agreement States as part of the National Materials Program. The goal is to give developers, regulators, and the public a more predictable framework. That is not just theoretical: the NRC has already identified early-stage commercial fusion activity in Agreement States, specifically in Massachusetts, Tennessee, and Washington.

Looking Ahead

The NRC will host at least one public meeting during the comment period. It has specifically requested feedback on several topics: (1) whether reporting thresholds for tritium should be adjusted for the large quantities that commercial fusion machines may use and produce, (2) the adequacy of the proposed waste disposal framework, and (3) whether additional export controls for fusion machines are warranted.

The NRC has also asked whether including fusion machines within the definition of “particle accelerator” could create unintended consequences. That question matters because some Agreement States have different particle-accelerator definitions and have already licensed fusion devices under those existing frameworks. That request is a reminder that, even though the NRC intends the proposal to be technology-inclusive and deregulatory, details about definitions and state-federal compatibility will matter in determining how smoothly the rule works in practice.

The NRC’s unified regulatory agenda targets a final rule by October 2026, well ahead of the Nuclear Energy Innovation and Modernization Act-mandated December 31, 2027 deadline.

Once finalized, this regulatory framework should provide a meaningful benefit to the fusion development community. The NRC is confirming that it will regulate fusion machines based on their actual risk characteristics, rather than squeezing them into a framework designed for fundamentally different fission technology. With companies seeking to construct facilities and targeting commercial deployment in the late 2020s and early 2030s, this rulemaking should help turn fusion’s immense promise into commercial reality.

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