Thorium Atomics Inc. has formally 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. The NRC has assigned Project No. 99902174 and a project manager to coordinate the pre-application activities, providing a defined point of contact and a trackable reference for future interactions. 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).
This administrative step does not imply NRC approval or endorsement of the Tesseract design; it simply establishes a formal channel for the company to engage with regulators early in the design process. The engagement will be conducted under 10 CFR Part 53, the NRC's risk-informed, performance-based, and technology-inclusive licensing framework, which became available for use on April 29, 2026. Thorium Atomics is preparing a Regulatory Engagement Plan that outlines the technology, licensing strategy, and sequence of pre-application submissions.
Dr. Jack Vecchiarelli, Chief Scientific and Regulatory Officer, emphasized the importance of starting engagement while the design is still evolving. "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."
The Tesseract TGR is a pebble-bed high-temperature gas-cooled reactor that uses helium as coolant and TRISO fuel, with a thorium-bearing fertile blanket designed to breed U-233 and improve uranium utilization. It is a small modular reactor with a thermal output of 250 MWth, delivering about 100 MWe or industrial process heat up to 750°C. This heat range is difficult to supply with electricity and is currently met mostly by combustion, so the reactor offers a low-carbon alternative for industrial applications.
Young Hwang, Founder and CEO, noted that this milestone aligns with other parallel efforts: "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 company's approach aims to diversify the nuclear fuel supply chain and reduce mined-uranium requirements by approximately half per unit of energy compared to a Generation II light-water reactor, though this estimate is subject to further design optimization and independent validation. By engaging with regulators early, Thorium Atomics is taking a proactive step to ensure that the Tesseract TGR meets all safety and performance requirements, potentially streamlining the path to commercialization.
