Thorium Atomics Inc., a developer of advanced nuclear reactors, announced that it has 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, assigning Project No. 99902174 and a project manager in the NRC’s Office of Advanced Reactors to coordinate pre-application activities.
The assignment of a project number is an administrative step that provides a tracking reference for future correspondence, meetings, and submissions. It does not constitute acceptance of a license application or NRC approval of the design. The notice letter is publicly available in the NRC’s Agencywide Documents Access and Management System (ADAMS) under Accession No. ML26189A392, and can be accessed directly at https://www.nrc.gov/docs/ML2618/ML26189A392.pdf.
Thorium Atomics plans to engage under 10 CFR Part 53, the NRC’s risk-informed, performance-based, and technology-inclusive licensing framework that became available on April 29, 2026. The company is preparing a Regulatory Engagement Plan detailing the Tesseract technology, licensing strategy, and planned submissions.
“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,” said Dr. Jack Vecchiarelli, Chief Scientific and Regulatory Officer. “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 high-temperature gas-cooled reactor that uses helium coolant and TRISO particle fuel. Its safety response relies on passive physical phenomena rather than active systems. The design is in development and not yet built or licensed. It is a small modular reactor with a thermal output of 250 MWth, delivering about 100 MWe of electricity or industrial process heat up to 750°C. The reactor uses uranium TRISO fuel enriched below 10% U-235, with a thorium-bearing fertile blanket that captures neutrons and converts thorium-232 into fissile uranium-233 during operation.
This uranium-fueled, thorium-augmented architecture aims to diversify the fuel supply chain and improve uranium utilization, potentially reducing mined-uranium requirements by about half per unit of energy compared to a Generation II light-water reactor. However, this estimate is subject to further engineering and independent validation.
The NRC’s assignment of a project number and project manager is a significant administrative milestone that enables structured pre-application engagement. By starting early, Thorium Atomics can align its design with regulatory expectations, potentially reducing future licensing risks and accelerating the path to deployment.
