TRISO-X, a wholly owned subsidiary of X-energy, has completed vertical construction of TX-1, its advanced nuclear fuel fabrication facility in Oak Ridge, Tennessee. The 214,000-square-foot structure is now ready for the next phase: interior fit-out, installation of production equipment, and completion of supporting infrastructure.
TX-1 is set to become the first commercially built advanced nuclear fuel fabrication facility constructed in the United States in over fifty years. Once fully operational, it will produce approximately 700,000 TRISO-X fuel pebbles per year — equivalent to five metric tons of uranium — with enough capacity to fuel up to eleven Xe-100 reactors. TRISO-X fuel consists of small uranium kernels encapsulated in three layers of ceramic and carbon materials, then embedded in spherical fuel elements. The fuel’s geometry builds safety directly into the material physics: in the event of a thermal anomaly, heat dissipates passively, with no need for active cooling systems.
Reaching this construction milestone required navigating a significant regulatory journey. The U.S. Nuclear Regulatory Commission issued TRISO-X a forty-year special nuclear material license — the first NRC Category 2 license ever granted for the processing of High-Assay Low-Enriched Uranium, known as HALEU. This type of uranium, enriched between 5% and 20% in U-235, is essential for next-generation advanced reactors. Its large-scale commercial production on American soil has long been a missing link in the domestic nuclear fuel supply chain.
The first planned use of fuel produced at TX-1 is tied to X-energy’s project at Dow Inc.‘s industrial site in Seadrift, Texas, where four Xe-100 reactors rated at 80 MW each are planned. The NRC approved the environmental review for that project in May. X-energy is also advancing the Cascade Advanced Energy program in Washington State, in partnership with Energy Northwest and Amazon. Last July, the State of Tennessee awarded the company an $11 million grant to support development of the fuel fabrication campus.
Joel Duling, President of TRISO-X, described the transition from exterior construction to interior equipment installation as a concrete shift toward actual production. Each milestone, in his words, brings the creation of a domestic source of advanced nuclear fuel — capable of sustaining America’s next-generation reactors — one step closer to reality. The broader project also includes a second facility, TX-2, with the stated goal of closing a structural gap in the nuclear fuel supply chain for the United States and its allies. If timelines hold, TX-1 could begin commercial production before the end of the decade, making industrially available for the first time a fuel that has for decades remained confined to the realm of research.
