The US Nuclear Regulatory Commission (NRC) will base its regulatory framework for fusion energy systems on its existing process for licensing the use of byproduct materials.
The divertor of the Trenta fusion generator prototype (Image: Helion Energy)
"Dozens" of companies are developing pilot-scale commercial fusion designs, NRC Chair Christopher Hanson said. While the "precise future" for fusion in the USA is uncertain, the agency should provide "as much regulatory certainty as possible given what we know today," he added. "Licensing near-term fusion energy systems under a byproduct material framework will protect public health and safety with a technology-neutral, scalable regulatory approach."
Fusion systems - described by the NRC as devices that contain nuclear fusion reactions as well as associated radioactive materials and supporting structures, systems and components - would generate electricity from the energy released when hydrogen atoms are combined to form helium, rather than the splitting, or fission, of uranium atoms. This means that such systems fall outside the requirements to be regulated by NRC as nuclear reactors, as they do not involve special nuclear material (plutonium, uranium-233 or enriched uranium) and cannot produce the self-sustained neutron chain reaction that defines nuclear fission reactors under NRC regulations.
Earlier this year, NRC staff outlined three suggested options for the licensing and regulation of fusion systems: categorisation as "utilisation facilities", with a new regulatory framework developed to address the associated specific hazards; a byproduct material approach, augmenting the existing regulatory for byproduct material licences; and a hybrid framework, in which the decision on whether a byproduct material or a utilisation facility approach would be more appropriate for a particular system would be based on the potential risks and hazards of that system. In its submission, the staff recommended a hybrid system should be adopted.
Tritium and other radioactive materials which occur or are used in fusion systems are normally categorised by the NRC as byproduct material, and the commission has now directed its staff to create a regulatory framework for fusion systems built on the agency's existing process for licensing the use of such materials.
NRC staff will now begin a "limited revision" to materials licensing regulations, including consideration of whether the revision should create a new rule category specifically for fusion energy systems, taking into account fusion systems "that already have been licensed and are being regulated by the Agreement States, as well as those that may be licensed prior to the completion of the rulemaking". The commission also directed staff to take several related actions, including expanding materials licence guidance to cover fusion systems nationwide.
The US Department of Energy last year announced up to USD50 million of federal funding to support experimental research in fusion energy science as part of the administration's "decadal vision" to accelerate fusion energy. Some commercial fusion systems are now expected to reach design proof-of-concept, and even net power production, as soon as the mid-to-late 2020s, with deployment projected to follow in the 2030s, according to the NRC.
One US developer of such a system, Helion Energy, expressed support for the NRC's announcement. "This approach provides a clear and effective regulatory path for our team to deploy clean, safe fusion energy," the company said on Twitter.
