In a milestone for the U.S. nuclear fuel cycle, the Nuclear Regulatory Commission (NRC) on Feb. 13 issued its first approval of a commercial Category II nuclear fuel fabrication facility, granting a license to TRISO-X, a wholly owned subsidiary of X-energy, which allows the company to fabricate commercial tristructural isotropic (TRISO) fuel using high-assay low-enriched uranium (HALEU) at its TRISO-X Fuel Fabrication Facility (TF3) under construction in Oak Ridge, Tennessee.
Issued under 10 CFR Part 70, the 40-year Special Nuclear Material (SNM-7007) license—expiring on Feb. 13, 2066—authorizes TRISO-X to receive, acquire, possess, and transfer special nuclear material, including uranium enriched to less than 20% U-235, for fuel fabrication at TF3, its greenfield facility which is under construction at the 110-acre Horizon Center Site in Oak Ridge, Tennessee.
While the NRC license applies to TF3 (referred to as TRISO-X FFF) as a single Part 70 fuel fabrication facility, the company refers to its first commercial fabrication unit at the site as “TX-1” and plans a second unit, “TX-2,” to expand production capacity. The license includes detailed safety and safeguards conditions and requires the NRC to complete an operational readiness review before uranium may be introduced into the facility.
X-energy is developing the commercial fuel facility to support commercial deployment of its Xe-100 high-temperature gas-cooled reactor (HTGR) design, which will use TRISO fuel composed of poppy-seed-sized uranium kernels encapsulated in multiple layers of carbon and ceramic materials. The coated particles are embedded in graphite to form spherical fuel elements, commonly referred to as “pebbles,” designed to retain fission products at elevated temperatures.
The company, which has operated a pilot-scale TRISO fuel line at Oak Ridge National Laboratory since 2016, submitted its Part 70 license application for the TRISO-X FFF to the NRC on April 5, 2022, followed by an environmental report on Sept. 23, 2022, and a supplemental application on Dec. 30, 2024. The project is part of X-energy’s participation in the U.S. Department of Energy’s Advanced Reactor Demonstration Program (ARDP).
Vertical construction at the first fuel facility, TX-1, began in November 2025, and according to the company, construction on the core and shell phase of the 214,812-square-foot facility is expected to be completed by mid-2026. TX-1 is expected to produce 5 metric tons of uranium (MTU) or 700,000 TRISO pebbles per year—enough fuel for up to 11 Xe-100 reactors. Operations are projected to start in 2027, and initial fuel production will likely support the four-unit 320-MWe Long Mott Generating Station planned for Dow’s Seadrift Operations in Texas, X-energy’s first commercial reactor.
Under NRC regulations (10 CFR 70.4), fuel fabrication facilities are categorized by the quantity and enrichment level of special nuclear material (SNM) they are authorized to possess. Category II facilities, such as TRISO-X, may handle special nuclear material of moderate strategic significance, including 10,000 grams or more of U-235 contained in uranium enriched to 10% or more but less than 20%—the HALEU enrichment range—in quantities that remain below the “formula quantity” of strategic special nuclear material that defines Category I facilities
By comparison, Category I plants may possess formula quantities of highly enriched uranium (20% or greater U-235), U-233, or plutonium and support missions such as naval reactor fuel production and weapons material down-blending. Category III facilities are limited to material of low strategic significance, including uranium enriched above natural uranium but less than 10% U-235, which is typical of conventional light water reactor (LWR) fuel. Category II facilities, notably, require physical protections applicable to SNM of moderate strategic significance under 10 CFR 73.67.
X-energy noted that before it receives SNM and officially kicks off operations at TX-1, the NRC will conduct a final inspection. “This inspection will verify that equipment is ready for service, required safety systems and items relied on for safety are installed and functional, and that license-mandated programs and procedures are in place. It will also confirm that operating personnel are trained and qualified to safely begin operations,” it said.
According to the NRC, the license application was approved three months ahead of the published schedule “due to multiple efficiencies applied in the staff’s review processes.” The NRC’s review included a safety and security review and an environmental review. A Safety Evaluation Report (SER) documenting the technical review will be made public within 30 days. The project’s Environmental Impact Statement (EIS), notably, was published Feb. 12, 2026—one day before the license was issued.
“Commercial-scale production of this fuel is key to enabling the deployment of advanced reactor designs,” said NRC Chairman Ho K. Nieh on Friday. “This license represents an important milestone that supports the Department of Energy’s program to accelerate deployment of nuclear technologies and deliver more power to the grid.”
For X-energy, the decision has been monumental. “Regulatory approval brings us one step closer to a resilient, American fuel supply for next-generation nuclear technology, advancing our energy security by closing a longstanding gap in the U.S. nuclear fuel cycle,” said Joel Duling, president of TRISO-X. “Achieving this first-of-its-kind license reflects the technical leadership and sustained diligence of the TRISO-X team, as well as a focused process with the NRC to complete the review three months ahead of schedule. We look forward to continuing our work to bring commercial-scale TRISO production to East Tennessee.”
The company noted that while TX-2 is currently in the design phase, it would “significantly scale TRISO fuel production capacity to support X-energy’s 11 GW commercial pipeline, equivalent to 144 Xe-100 small modular reactors, as well as other SMR developers.”
Full-scale production at TX-1 and TX-2 “is expected to establish a stable commercial source of TRISO fuel for the first time in U.S. history, directly supporting energy and national security priorities by helping to close a major gap in the current U.S. and allied nuclear fuel cycle,” it said.
—Sonal Patel is a POWER senior editor (@sonalcpatel, @POWERmagazine).
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