Thorium Atomics Inc., an advanced nuclear reactor developer with offices in Toronto and Knoxville, announced today that it has begun pre-application regulatory engagement with the U.S. Nuclear Regulatory Commission (NRC) for its Tesseract TGR 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 within the Office of Advanced Reactors to coordinate pre-application activities.
The assignment of a project number is an administrative step that facilitates tracking of future correspondence, meetings, and submissions, but it does not constitute an application or imply NRC approval of the design. The company 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. Thorium Atomics is preparing a Regulatory Engagement Plan outlining its licensing strategy and planned submissions.
Dr. Jack Vecchiarelli, Chief Scientific and Regulatory Officer, emphasized the importance of early engagement: “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 high-temperature gas-cooled reactor that uses helium as coolant and TRISO particle fuel. It is designed for a thermal output of 250 MWth, delivering approximately 100 MWe of electricity or industrial process heat at temperatures up to 750°C. The reactor uses uranium TRISO fuel enriched below 10% U-235 as an initial driver and incorporates a thorium-bearing fertile blanket to breed U-233, potentially reducing mined-uranium requirements by about half per unit of energy compared to a Generation II light-water reactor. These estimates are subject to further engineering and independent validation.
Thorium Atomics is also maintaining a parallel regulatory pathway with the Canadian Nuclear Safety Commission. The company’s notice of intent letter is publicly available in the NRC’s ADAMS system under Accession No. ML26189A392, accessible via this direct link.
This development is significant because it represents a concrete step toward licensing an advanced reactor under the newly available Part 53 framework, which could set a precedent for other advanced reactor designs. By engaging early, Thorium Atomics aims to identify and address regulatory expectations before submitting a formal application, potentially reducing licensing time and cost. The use of thorium augmentation also highlights efforts to diversify nuclear fuel supply and improve fuel utilization, aligning with broader industry goals for sustainable nuclear energy.
