Fusion Energy Regulation in the United States: Frameworks for Licensing and Deployment

Introduction

The United States is entering a new phase in the development of fusion energy. After decades of scientific progress and growing private-sector investment, multiple companies are now working toward demonstrating commercial fusion systems in the next decade to meet rising energy demand with affordable, reliable, and clean energy. As fusion technologies move closer to deployment, establishing a clear and predictable regulatory path will be an essential step in enabling demonstration projects, attracting investment, and ensuring public safety and confidence in fusion energy.

In response to this emerging industry, U.S policymakers and regulators have formalized the regulatory frameworks that will be used for licensing of near-term fusion energy facilities. Rather than using existing regulatory frameworks for licensing nuclear fission reactors, legislators and regulators have decided to regulate fusion energy by adapting existing regulatory frameworks for licensing the use of radioactive materials. This decision reflects the expected hazards of near-term fusion machines, the suitability of existing regulatory frameworks for radioactive materials to address those risks, and the desire of the commercial fusion industry’s need for a predictable regulatory framework that enables the investment and demonstration of commercial fusion machines.

The NRC closed the public comment period on its proposed regulatory framework for fusion energy in late May 2026 and began the process to finalize the regulations and regulatory guidance for commercial fusion energy. This paper summarizes the history of fusion energy regulation in the United States to date, the proposed regulatory framework that will be used to license and regulate fusion power plants, and a brief introduction to the processes that will be required for licensing. While the NRC is not expected to publish the final fusion machine rules and guidance until 2027, understanding the general processes can help prepare stakeholders for important licensing discussions in the next several years. 

The history of fusion energy regulation in the United States

From the 1960s-1980s, regulation of early fusion machines in the United States was overseen by the U.S. Department of Energy (DOE). Specifically, the DOE regulated the Tokamak Fusion Test Reactor (TFTR) at Princeton Plasma Physics Laboratory (PPPL) as a non-reactor radiological facility (DOE Hazard Category III). This regulatory decision was based on the design of TFTR and the limited radiological material inventory (2.5 grams tritium in any single active system and up to 5 grams of tritium on-site).

In the 1990s, DOE began developing regulatory guidance to support potential siting of the ITER project in the United States. The regulatory development was led by the Idaho National Laboratory (INL) but focused primarily on the technical evaluations of fusion machine safety within the existing DOE regulatory framework. Potential regulatory frameworks for commercial fusion energy deployment were not yet discussed.

In 2009, the U.S. Nuclear Regulatory Commission (NRC) provided the first formal decision on the regulation of fusion energy. The Commission vote on staff paper SECY-09-0064 approved the staff’s recommendation to assert that “as a general matter… the NRC has regulatory jurisdiction over commercial fusion energy” but that the staff should wait to develop a regulatory framework for fusion technology until there was further commercial progress on development and deployment of fusion energy technology.

The U.S. Congress initiated the current regulatory framework for fusion energy in 2019 with the passage of the Nuclear Energy Innovation and Modernization Act (NEIMA). NEIMA included “fusion energy” in the definition of “advanced nuclear energy” and directed the NRC to complete a rulemaking process to develop a novel regulatory framework for advanced nuclear energy by 2027. As a result, NEIMA created the legislative impetus for developing fusion energy regulation in the United States.

In April 2020, NRC staff provided a rulemaking plan to NRC Commissioners outlining their recommendations on how to complete NEIMA’s congressional directives. The NRC Commissioners voted to begin the rulemaking process for advanced fission reactors, but directed staff to develop other options for “appropriate treatment” of fusion energy and provide options to the Commission for additional direction. The Commission’s decision initiated 15 months of public meetings and discussions with NRC staff and external stakeholders on the regulatory options for commercial fusion energy. This also included discussions on which NRC regulations in Title 10 of Code of Federal Regulations (10 CFR) would be used to license and regulate fusion energy.

In January 2023, NRC staff provided an options paper for NRC Commissioners with three viable proposals for the regulation of fusion energy. The three options were:

• Option 1 – Regulate fusion energy systems under a utilization facility framework used for fission reactors (10 CFR Part 50 and 10 CFR Part 52)
• Option 2 – Regulate fusion energy systems under a byproduct material framework used for medical, industrial, and academic uses of radioactive materials (10 CFR Part 30)
• Option 3 – Regulate fusion energy systems under a hybrid framework using either a byproduct material or utilization facility approach based on standardized criteria or on a case-by-case assessment of potential hazards of each fusion machine.

The NRC staff recommended Option 3, stating that a hybrid approach would enable NRC staff to “appropriately license and regulate fusion energy systems based on their potential hazards.”

In April 2023, the NRC ultimately voted to approve Option 2 and regulate fusion energy systems using the byproduct materials framework. The Commission vote clarified that if “an anticipated fusion design presents hazards sufficiently beyond those of near-term fusion technologies,” then NRC staff should notify the Commission and make recommendations on future regulatory frameworks. The Commission directed the NRC staff to begin preliminary rulemaking to create the regulatory changes and regulatory guidance needed to support fusion energy licensing using the byproduct materials framework.

One major implication of regulating fusion energy under the byproduct materials framework in 10 CFR Part 30 is that regulation of fusion energy can be completed by certain state agencies. Under the NRC Agreement State Program, the NRC gives primary authority to individual states to regulate certain uses of byproduct, source, or special nuclear materials used or possessed within their jurisdiction if a state can demonstrate that they have compatible and capable state-level regulatory program. For example, as an NRC Agreement State, the use and possession of radioactive materials and radiation producing machines is regulated in Tennessee by the Division of Radiological Health within the Tennessee Department of Environment and Conservation. Regulation of fusion energy using the byproduct materials framework enables states to assume authority for the licensing and regulation of fusion power plants and facilities.

Congress eventually codified the NRC Commission decision with the passage of the “Accelerating Deployment of Versatile, Advanced Nuclear for Clean Energy Act” or  “ADVANCE Act,” in July 2024. The ADVANCE Act formally clarified that fusion machines were classified as a subset of particle accelerators and would therefore be regulated under the byproduct materials framework in 10 CFR Part 30. This decision provided regulatory certainty for the U.S. fusion industry.

In December 2024, NRC staff completed the development of the proposed rule and regulatory guidance for commercial fusion energy in the United States. The NRC published the proposed rule for fusion energy and associated regulatory guidance on February 26, 2026, with a 90-day public comment period and at least one public meeting. NRC staff will incorporate feedback from the public comment period into the proposed rule and respond to comments in 2026 and 2027.  The NRC is required by NEIMA to complete the fusion rulemaking and publish the final rule by December 31, 2027.

The NRC’s decision to regulate fusion energy under the radioactive byproduct materials framework in coordination with NRC Agreement States reflects the U.S. government’s determination that near-term prototype fusion machines would be regulated more effectively, efficiently, and predictably by using the existing regulatory framework for radioactive materials rather than by adapting the existing regulatory framework for fission reactors or creating of an entirely new regulatory regime. Regulation of fusion machines is already underway in several states, though states will need to update their regulations and make conforming changes following completion of the NRC rulemaking process.

Figure 1. Summary Timeline of U.S. Fusion Energy Regulation

NRC agreement states and assumed regulatory responsibility

The authority for the regulation and licensing of byproduct materials in the United States is shared between states and the federal government through the NRC Agreement State Program. The NRC Agreement State Program was established in 1959 through an amendment to the Atomic Energy Act (AEA) and enabled states to cooperate with the federal government and assume regulatory authority for specific licensing activities. Section 274 of the AEA outlines how state governors can enter into agreements with the NRC to assume authority for the licensing of byproduct materials, source materials (e.g., natural uranium), and limited quantities of special nuclear material (e.g., enriched uranium). States cannot assume regulatory authority for other NRC licensed activities such as fission reactors and fuel cycle facilities or radioactive waste disposal (AEA Section 274(c)).

States may become an NRC Agreement State through a formal agreement between the state governor and the NRC. NRC Agreement States are required to establish and maintain radiation control programs “adequate to protect the public health and safety” and assume the regulatory responsibility for any licenses and materials (AEA Section 274(d)(1)). The NRC must find that a state’s radiation control programs for byproduct and other radioactive materials are “compatible with the Commission’s programs for the regulations of such materials” and is effectively implemented for the materials regulated by the state (AEA Section 274(d)(2)). A state is not required to assume regulatory responsibility for all materials; the NRC retains regulatory responsibility for any licensing activities not assumed by the states (AEA Section 274(b)).

While states may assume regulatory responsibility for certain licensing activities, the AEA directs the NRC to actively engage with Agreement States to ensure effective licensing, program implementation, and the “formulation of standards for protection against hazards of radiation to assure that State and Commission programs for protection against hazards of radiation will be coordinated and compatible” (AEA Section 274(g)). The NRC is also tasked with providing trainings, support, and assistance to NRC Agreement States (AEA Section 274(i)). NRC Agreement States will maintain regulatory responsibility under their agreement with the NRC unless the agreement is either withdrawn at the request of the state’s governor or the NRC reviews the state program and finds cause for suspension or termination of the agreement (e.g., failure to comply with agreement conditions or determination that suspension or termination is “required to protect the public health and safety”) (AEA Section 274(j)).

The NRC Agreement State Program has enabled states to lead on the regulation and licensing of activities that were historically under the jurisdiction of state health and safety regulators before the passage of the Atomic Energy Act of 1954 (e.g., x-ray machines, naturally occurring radioactive materials, particle accelerators, and radioisotopes produced from particle accelerators). The program allows states to proactively address “the complicated task of balancing the state’s interest in attracting industrial atomic activities within their borders with that of providing adequate health and safety protection for their citizens.” The decision in the 1959 AEA amendments to create the NRC Agreement State Program recognized that certain regulatory responsibilities were clearly within the technical capacity and expertise of states and that the states would be excluded from regulatory responsibilities where “technical safety considerations were of such complexity that it was not likely that any state would be prepared to deal with them during the foreseeable future.” This balancing act in the NRC Agreement State Program allowed for state assumption of regulatory responsibility for specific activities in which they already had experience and expertise, while continuing NRC regulatory responsibility for highly complex regulated activities or regulated activities that have interstate or international implications.

Most U.S. states and territories have entered into agreements with the NRC to assume regulatory responsibility for some or all the statutorily allowed licensing and regulatory functions. As of December 31, 2025, there are 40 NRC Agreement States and 14 states and territories fully regulated by the NRC. Two of the 14 NRC-regulated states (Indiana and West Virginia) have submitted letters of intent with the NRC to create compatible state regulatory programs and enter into state agreements with the NRC. Figure 2 shows a map of the NRC Agreement State status in the United States.

Figure 2. NRC Agreement State Status Map (December 31, 2025)

The NRC Agreement State Program contributes to the overall mission of the NRC to protect public health and safety while still enabling flexible regulation that can meet the challenges of emerging radiation technologies and the needs of individual states. The NRC has previously stated that successful implementation of the NRC Agreement State Program is based on the following five program characteristics:

• Incorporation of NRC principles: State regulator incorporation of the NRC Principles of Good Regulation into their state level regulatory frameworks. The five NRC Principles of Good Regulation are independence, openness, efficiency, clarity, and reliability.
• Regular performance evaluations: Regular performance evaluations of state regulators and regulatory frameworks to ensure adequate protection of public health and safety, and to ensure compatibility of NRC Agreement State programs with NRC regulations and guidance.
• Adequate authority and resources: State regulators must have “requisite supporting legislative authority, implementing organization structure and procedures, and financial and human resources” needed to implement a compatible NRC Agreement State regulatory program.
• Consistent regulatory philosophy: State regulations and implementation should be based on a “common regulatory philosophy” with consistent definitions and standards to both provide uniformity across NRC and NRC Agreement State programs, and “achieve common strategic outcomes in program areas of national significance.”
• Flexibility in implementation: Flexibility in program implementation at the state level (where possible) to “accommodate individual State preferences, State legislative direction, and local needs and conditions” with the condition that the “requirements for adequate protection of public health and safety are met and compatibility is maintained.”

NRC Agreement States are given flexibility to implement regulatory requirements and processes for byproduct and other radioactive materials with the condition that it is fundamentally consistent and compatible with NRC regulation and guidance, and that the program is adequately implemented to protect public health and safety.

Proposed regulatory process for fusion machines in the United States

The general regulatory requirements for byproduct materials in the United States are presented in 10 CFR Part 30. Part 30 contains “rules of general applicability” for byproduct materials licenses, but the regulatory requirements may be challenging to implement because they are broadly written to include all possible uses of byproduct material such as medical isotope production and use, industrial irradiators, or x-ray and other radiation machines. The NRC instead uses program-specific regulatory guidance in the NUREG-1556 technical report series to provide reference information and generally accepted licensing approaches to meet the Part 30 regulatory requirements for specific applications. Examples of the NUREG-1556 program specific guidance include:

• NUREG-1556 Volume 2: Program-Specific Guidance About Industrial Radiography Licenses
• NUREG-1556 Volume 13: Program-Specific Guidance About Commercial Radiopharmacy Licenses
• NUREG-1556 Volume 17: Program-Specific Guidance About Special Nuclear Material of Less Than Critical Mass Licenses

The NRC is developing a new volume of NUREG-1556 to provide reference information and generally accepted licensing approaches for fusion energy in NUREG-1556, Volume 22. The NRC published a draft of NUREG-1556, Volume 22 for public comment on February 26, 2026, with a 90-day public comment period. While the final regulatory guidance for fusion machines may change based on public comments, the overall process for licensing fusion energy will still be based on the generally applicable regulations in 10 CFR Part 30. It is possible to characterize the expected licensing process for fusion energy based on the existing regulations in 10 CFR Part 30 and the high-level guidance presented in the published draft of NUREG-1556, Volume 22.

The regulatory requirements for fusion machines using 10 CFR Part 30 will be largely set by existing regulations that apply to all NRC and NRC Agreement State licensees. These regulations include radiation protection limits (10 CFR Part 20), physical security for radioactive materials (10 CFR Part 37), environmental protection (10 CFR Part 51), disposal of radioactive materials (10 CFR Part 61), and packaging and transportation of radioactive materials (10 CFR Part 71). Additional regulations (e.g., 10 CFR Parts 32 – 36 and Part 39) may be applicable to fusion machines and are detailed in the published draft of NUREG-1556, Volume 22.

The regulatory requirements in 10 CFR Part 30 help to define what additional information from an applicant is needed to receive a byproduct material license, and what specific conditions may apply to a licensee. An application will be approved if it meets the following conditions:

• Proposed use of byproduct material is authorized by the AEA
• Proposed equipment and facilities are adequate to protect health and minimize danger to life or property
• Proposed operator is qualified by training and experience to use the byproduct material in such manner as to protect health and minimize danger to life or property
• The application meets all applicable regulations (10 CFR Parts 30 – 36 and Part 37)
• The application meets all applicable environmental requirements (10 CFR Part 51)

The regulatory guidance in the published draft of NUREG-1556, Volume 22 outlines the major items needed in the application include:

• Information on proposed equipment, facilities, training and experience, and radiation safety and security programs will meet the regulatory requirements
• Details on how the licensee will implement fundamental regulatory principles such as keeping exposures as low as is reasonably achievable (ALARA), minimizing radioactive contamination, and maintaining control of radioactive materials
• Report on the potential environmental impacts of the proposed fusion machine during construction, operation, and decommissioning

Application contents for fusion machines are structured to facilitate applications and regulatory reviews that are proportional to the hazards and risks of the fusion machine. Fusion machines that have higher hazards and risks may be required to submit additional information in their application than fusion machines that have much smaller hazards.

For example, if a fusion machine proposed to have less than 20,000 Curies (approximately 2 grams) of tritium in an “unsealed form”, they are not required to submit either analyses that quantify off-site impacts of radioactive material releases or an emergency plan for responding to a release of radioactive material. If a fusion machine has greater than 20,000 Curies of tritium, they can choose to submit either an analysis “showing that the maximum dose to a person offsite due to a release of radioactive materials would not exceed 1 rem effective dose equivalent” or submit an off-site emergency plan. In this way, applicants have flexibility to either demonstrate that they do not have significant off-site risks by design and operation (by limiting doses to less than 1 rem) or can choose to have an off-site emergency plan that describes how accidental releases could be effectively detected and mitigated. If a fusion machine has greater than 20,000 Curies of tritium and cannot show that off-site impacts are less than 1 rem, they can still be licensed under the Part 30 regulatory framework but they must submit an emergency plan. Proportional regulatory requirements and oversight based on hazards can enable more effective regulation for a wide variety of fusion machines in Part 30.

Additional application information that could be expected for a fusion machine (e.g., decommissioning plans and decommissioning funding plans) is available in the published draft of NUREG-1556, Volume 22 (Section 8.10.9), but the specific contents of this regulatory guidance document may change during the public comment process.

Unlike applications for fission reactors, applicants will not be expected or required to submit comprehensive information about the fusion machine or power plant. The focus of the application review is on ensuring adequate processes, programs, and controls (both engineered and operational) and not on independent evaluation and confirmation of the design basis or operation of the machine. The license for a fusion machine is limited in scope: “the applicant only needs to provide information applicable to radioactive material present used, stored, or produced as part of their fusion operations.” Both the breadth and depth of information submitted for an application will vary based on the application and the information needed to support a finding that the licensee will “protect health and minimize danger to life or property” during construction, operation, and decommissioning.

It is important to note that this limited regulatory review does not limit the ability of the regulator (either NRC or an NRC Agreement State) to impose license terms and conditions to ensure safety. As part of any byproduct material license, the regulator may impose specific licensing requirements on design, operational, process, or programmatic elements deemed necessary to “protect health and minimize danger to life or property.” These specific license conditions could be developed generically for similar fusion machines or determined on a license-by-license basis. It is hard to assess at this time what generic conditions may be appropriate for fusion technology due to the diversity of designs, the limited design information available, and the early stage of machine commercialization. License-specific conditions will likely be a main point of discussion between regulators and applicants during pre-application and reviews; understanding and implementation of the license-specific conditions will evolve as regulators and applicants gain experience with fusion machines.

The licensing process for fusion machines within the 10 CFR Part 30 byproduct materials framework is still under development by the NRC. Until regulations and regulatory guidance are finalized, the regulation of fusion energy will still be completed on an ad-hoc basis by the NRC and NRC Agreement States based on regulatory precedent for particle accelerators, byproduct materials, and other radiation machines. The finalization of new regulations and guidance for fusion machines will require NRC Agreement States to update their programs to comply with and align with the updated NRC requirements. The specific implementation of the updated requirements may vary on a state-by-state basis based on the flexibility afforded to states by the AEA and it is not possible at this time to accurately predict the final regulatory requirements, frameworks, or processes in each state.

Conclusions on regulation of fusion energy through the NRC Agreement State Program

The regulatory considerations for fusion energy will resemble those for byproduct materials, radiation sources, and other radioactive materials, rather than those for special nuclear materials, nuclear fission reactors, or nuclear fuel cycle facilities. Fusion machines will not be subject to fission reaction criticality safety or special nuclear material accountability requirements based on tracking significant quantities of fissionable materials. Instead, fusion energy safety will focus on the confinement and control of sealed and unsealed radioactive materials, and on the operational safety of machines through engineered controls, operator actions, and administrative controls and programs. These challenges align more closely with the licensing requirements applied to byproduct materials and other radioactive sources already managed by NRC Agreement States and the NRC’s Office of Nuclear Materials Safety and Safeguards for non-agreement states.

NRC staff will continue to evaluate the development of commercial fusion energy in the United States and assess if additions or modifications to the licensing processes are required for future fusion machines (per Commission direction). It is clear, however, that fusion energy in the United States will be regulated in a fundamentally different way than fission energy. This fit-for-purpose and proportional licensing process will provide regulatory certainty, which is critical to supporting investment in the research, development, and deployment of commercial fusion energy in the United States.

Figure 3. Full Timeline of U.S. Fusion Energy Regulation