Thorium Atomics Inc. has officially commenced pre-application regulatory engagement with the U.S. Nuclear Regulatory Commission (NRC) for its Tesseract TGR advanced reactor. The company submitted a notice of intent letter on June 23, 2026, and the NRC responded on July 24, 2026, by assigning Project No. 99902174 and designating a project manager in the NRC's Office of Advanced Reactors to coordinate pre-application activities. The project number provides an administrative tracking reference for future correspondence, meetings, submissions, and staff reviews. The notice letter is publicly available in the NRC's Agencywide Documents Access and Management System (ADAMS) under Accession No. ML26189A392. Direct link: https://www.nrc.gov/docs/ML2618/ML26189A392.pdf.
The assignment of a project number is an administrative step and does not constitute submission or acceptance of a license application, nor does it represent NRC approval, endorsement, or certification of the Tesseract TGR design. Thorium Atomics plans to engage with the NRC under 10 CFR Part 53, the agency's risk-informed, performance-based, and technology-inclusive licensing framework for commercial nuclear power plants, which became available for use on April 29, 2026. The company is preparing a Regulatory Engagement Plan describing the Tesseract technology, its proposed licensing strategy, and the sequence of planned pre-application submissions.
Dr. Jack Vecchiarelli, Chief Scientific and Regulatory Officer at Thorium Atomics, emphasized the importance of this milestone: "A project number and an assigned project manager give us a defined NRC point of contact and a trackable reference for our future pre-application work. Part 53 is risk-informed and technology-inclusive, making it well suited to a high-temperature gas-cooled reactor. Commencing that engagement while the design is still being developed serves to ensure that regulatory expectations are clearly understood and addressed, thereby informing the design development process and helping to de-risk the future licensing pathway."
Young Hwang, Founder and CEO, added: "This is a clear external marker of where our program stands. It comes alongside our application to Idaho National Laboratory's Nuclear Energy Launch Pad program and our proposed pathway for independent, qualified-code reactor-physics verification at a U.S. national laboratory. We are deliberately building the regulatory, engineering, and technical-validation records in parallel."
The Tesseract TGR is a pebble-bed type high-temperature reactor, using helium as a coolant and coated-particle TRISO fuel. Its safety response is enabled by passive physical phenomena rather than active systems. The design is a small modular reactor with a thermal output of 250 MWth, delivering approximately 100 MWe of firm electricity or industrial process heat at temperatures up to 750 degrees Celsius. The reactor uses uranium TRISO fuel enriched below 10% U-235 as its initial fissile driver, with a thorium-bearing fertile blanket designed to convert thorium-232 into fissile uranium-233 during operation. This architecture is intended to diversify the nuclear fuel supply chain and improve lifetime uranium utilization. Current analysis estimates a reduction in mined-uranium requirements by approximately half per unit of energy relative to a comparable Generation II light-water reactor, subject to further engineering and validation.
Thorium Atomics is an advanced nuclear reactor developer with offices in Toronto, Ontario, and Knoxville, Tennessee. The company is conducting pre-application activities with the U.S. NRC and maintaining a parallel regulatory pathway with the Canadian Nuclear Safety Commission. Further information is available at thoriumatomics.com.
