NRC Issues Proposed Rule Establishing Licensing Framework for Fusion Machines

The NRC describes the proposal as limited in scope, technology-inclusive and risk-informed, focused on near-term fusion designs and consistent with the Commission’s April 2023 direction to regulate fusion under Part 30. The agency also notes that Agreement States have safely regulated laboratory-scale fusion research and development systems for more than 25 years under Part 30-compatible programs.

Fusion Machines Treated as Particle Accelerators
Consistent with Section 205 of the ADVANCE Act of 2024, the proposal revises the definition of “byproduct material” to include material made radioactive by use of a particle accelerator, “including by use of a fusion machine.” “Fusion machine” is defined as a machine capable of transforming atomic nuclei through fusion processes and directly capturing and using the resultant products (including particles, heat and electromagnetic radiation), and the “particle accelerator” definition is updated to expressly include fusion machines. These revisions thus align NRC regulations with Congress’s clarification in the ADVANCE Act that fusion machines fall within the particle accelerator and byproduct material provisions of the AEA rather than in the statutory framework applicable to nuclear reactors.

“Near-Term” Terminology
The NRC stated that the rule applies to “near-term” fusion machines. The NRC clarified that the phrase is defined by a fusion machine’s operational characteristics rather than a particular timeframe. Under the NRC’s definition, “near-term” refers to machines that do not involve fissile material or criticality, do not require active post-shutdown cooling to maintain confinement, are expected to result in low offsite doses in credible accident scenarios—e.g., less than 1 rem (10 mSv)—and rely on active engineered systems to sustain fusion. As such, it encompasses both R&D and proof-of-concept facilities and full-scale fusion machines currently being contemplated for commercial deployment.

Proposed and Amended Requirements
As proposed, the rule requires fusion developers to apply for a specific license under Part 30 to possess, use or produce byproduct material. It further requires applicants and licensees to satisfy several technical and compliance requirements.

Applicants seeking authorization to possess specified quantities of byproduct material must demonstrate how they will satisfy financial assurance or decommissioning funding plan requirements. Once licensed, they must comply with existing security and accountability requirements and implement additional physical protection measures under Part 37 to possess specified threshold quantities of byproduct material. Licensees are also required to maintain records, including those related to the production of tritium and activation products.

For threshold quantities of unsealed radioactive material identified in Schedule C to Part 30, applicants must demonstrate that a potential offsite release would not exceed certain effective dose equivalents or submit an offsite emergency plan. Unless a categorical exclusion applies, applicants must submit an environmental report under Part 51 for the construction and operation of a fusion machine and separately must demonstrate that their proposed byproduct material disposal method complies with the Part 61 low-level radioactive waste framework.

Because fusion machines do not use or produce nuclear material subject to International Atomic Energy Agency safeguards, exports of fusion equipment generally fall under U.S. Department of Commerce (DOC) rather than NRC export control jurisdiction. Materials such as deuterium and tritium remain subject to existing export controls under the AEA and applicable DOC regulations, depending on end use.

Next Steps
The proposed rule largely formalizes the Commission’s previously announced policy choice to regulate near-term fusion technologies under the byproduct material framework. Comments on the proposed rule are due on May 27, 2026, 90 days after the rule’s publication in the Federal Register.

Fusion developers, investors and host states should review the proposal given its likelihood to shape the regulatory pathway for commercial fusion deployment in the United States. Pillsbury’s Fusion Energy team is monitoring this rulemaking and is available to assist clients in evaluating licensing strategies, Agreement State considerations, environmental review planning and compliance obligations as the NRC moves from proposal to final rule.