Thorium Atomics Inc. has officially commenced pre-application regulatory engagement with the U.S. Nuclear Regulatory Commission (NRC) for its Tesseract TGR advanced reactor, following the submission of a notice of intent letter and the NRC's subsequent assignment of a project number and project manager.
The company submitted its notice of intent on June 23, 2026, and by July 24, the NRC assigned Project No. 99902174 and designated a project manager in the Office of Advanced Reactors to coordinate pre-application activities. This project number will serve as an administrative reference for all future correspondence and submissions, and the notice letter is publicly available in the NRC's ADAMS system under Accession No. ML26189A392. The assignment is an administrative step and does not constitute acceptance or approval of the design.
Thorium Atomics plans to engage under 10 CFR Part 53, the NRC's risk-informed, performance-based, and technology-inclusive framework that became available on April 29, 2026. The company is preparing a Regulatory Engagement Plan detailing its technology and licensing strategy. Dr. Jack Vecchiarelli, Chief Scientific and Regulatory Officer, emphasized that Part 53 is well-suited for high-temperature gas-cooled reactors and that early engagement helps clarify expectations and de-risk the path forward.
Young Hwang, Founder and CEO, highlighted that this milestone complements their application to Idaho National Laboratory's Nuclear Energy Launch Pad program and their proposed pathway for independent reactor-physics verification at a U.S. national laboratory. The company is building its regulatory, engineering, and technical-validation records in parallel.
The Tesseract TGR is a pebble-bed high-temperature gas-cooled reactor that uses helium as a coolant and TRISO fuel, providing passive safety features. It is designed for 250 MWth and approximately 100 MWe of firm electricity or industrial process heat up to 750°C, which is currently supplied mostly by combustion. The reactor uses uranium TRISO fuel enriched below 10% U-235 and incorporates a thorium-bearing blanket to convert thorium-232 into fissile uranium-233, potentially reducing mined-uranium requirements by about half compared to Generation II light-water reactors. This estimate is subject to further validation.
The company, with offices in Toronto and Knoxville, is also maintaining a parallel regulatory pathway with the Canadian Nuclear Safety Commission. This pre-application engagement marks a significant step toward commercializing the Tesseract TGR, aiming to provide clean, firm power and high-temperature heat while diversifying the nuclear fuel supply chain.
