Thorium Atomics Begins NRC Pre-Application Engagement for Tesseract TGR

Thorium Atomics Inc., an advanced nuclear reactor developer with offices in Knoxville, Tennessee, 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 by assigning Project No. 99902174 and a dedicated project manager in its Office of Advanced Reactors. This administrative step provides a defined point of contact and a trackable reference for future interactions, but does not constitute an application or approval.

The engagement will proceed under 10 CFR Part 53, the NRC's risk-informed, performance-based, and technology-inclusive licensing framework for commercial nuclear power plants, which became available on April 29, 2026. Thorium Atomics is preparing a Regulatory Engagement Plan that outlines the Tesseract technology, its licensing strategy, and a sequence of pre-application submissions. Dr. Jack Vecchiarelli, Chief Scientific and Regulatory Officer, emphasized that Part 53 is well-suited for high-temperature gas-cooled reactors and that starting engagement early helps ensure regulatory expectations are understood and addressed, thereby informing design development and de-risking the future licensing pathway.

The Tesseract TGR is a pebble-bed high-temperature gas-cooled reactor that uses helium as a coolant and TRISO fuel. It is designed for a thermal output of 250 MWth, delivering approximately 100 MWe of firm electricity or industrial process heat at temperatures up to 750 degrees Celsius—a temperature range that is difficult to supply with electricity and currently met almost entirely by combustion. The reactor uses uranium TRISO fuel enriched below 10% U-235, with a thorium-bearing fertile blanket that captures neutrons to convert thorium-232 into fissile uranium-233, potentially reducing mined-uranium requirements by about half per unit of energy compared to a Generation II light-water reactor. This estimate is subject to further engineering and independent validation.

Young Hwang, Founder and CEO, noted that this milestone comes alongside the company's application to Idaho National Laboratory's Nuclear Energy Launch Pad program and a proposed pathway for independent, qualified-code reactor-physics verification at a U.S. national laboratory. He stated, "We are deliberately building the regulatory, engineering, and technical-validation records in parallel." This approach aligns with the company's goal of diversifying the nuclear fuel supply chain and improving lifetime uranium utilization while grounding the fuel and licensing pathway in established uranium and TRISO-fuel infrastructure.

The NRC's notice of intent letter is publicly available in the Agencywide Documents Access and Management System (ADAMS) under Accession No. ML26189A392, accessible at https://www.nrc.gov/docs/ML2618/ML26189A392.pdf. This administrative step does not represent NRC approval or endorsement of the Tesseract TGR design, but it marks a formal start to the pre-application process.

Thorium Atomics, with offices in Toronto and Knoxville, is also maintaining a parallel regulatory pathway with the Canadian Nuclear Safety Commission. The company's focus on high-temperature process heat could have significant implications for industries that rely on combustion, offering a potential low-carbon alternative. As the design is still under development and not yet built or licensed, the company's proactive engagement with regulators is a critical step toward commercial deployment, which could eventually benefit Texas and other regions by providing firm, clean electricity and industrial heat.