TRISO Fuel Manufacturers: Production, Qualification and Reactor Customers
60-second answer: Four organizations manufacture or are building capacity for TRISO fuel in the US: BWXT (the only one with decades of deliveries, including the full Project Pele core shipped in November 2025), X-energy's subsidiary TRISO-X (licensed February 2026, plant under construction, targeting 5 tonnes of uranium a year), Standard Nuclear (running a ~500 kg/yr pilot line on former USNC assets, expanding), and Kairos Power (in-house pilot pebbles plus a BWXT partnership for commercial volumes). Fabrication is its own bottleneck in the advanced-fuel chain: a reactor can have funding, a license and even HALEU feedstock and still wait on a qualified fuel plant.
Enriched uranium is not fuel. For most advanced reactor designs the step that turns HALEU into something loadable is TRISO fabrication, and the companies that can do it form a short, specific list with very different track records.
What TRISO fuel is
A TRISO (tristructural isotropic) particle is a uranium kernel wrapped in four engineered layers: a porous carbon buffer, an inner pyrolytic carbon layer, a silicon carbide layer that acts as the primary containment for fission products, and an outer pyrolytic carbon layer (X-energy, TRISO-X fuel; DOE explainer). Each particle is smaller than a millimeter. Particles are then pressed into a usable macro-form: billiard-ball-scale pebbles for pebble-bed reactors (X-energy, Kairos) or cylindrical compacts for prism and monolith cores (BWXT's Pele core, eVinci). The particle is the containment; the pebble or compact is the handling format.
Two consequences follow. Particle count is not a uranium quantity: capacity claims need a kgU-per-year basis, since a pebble contains grams of uranium inside much more graphite. And the fuel form is distinct from its enrichment: today's US TRISO programs use HALEU kernels, but TRISO is a geometry, not an assay.
Who makes it: the dated supplier table
Verified September 17, 2026. Demonstrated deliveries, licensed scope and planned capacity are different columns on purpose; they are never summed on this site.
| Manufacturer | Plant | Demonstrated (dated) | Licensed / permitted scope | Planned capacity | Named customers |
|---|---|---|---|---|---|
| BWXT | Lynchburg VA (Specialty Fuels) | Full Project Pele core delivered to INL Nov 5, 2025: 40,000 compacts; 20+ years of TRISO for government programs (BWXT) | Existing Cat I fuel operations (government work) | Commercial TRISO line with Kairos under a Sep 2025 teaming agreement (WNN) | US DoD (Pele); Kairos (commercial) |
| TRISO-X (X-energy) | TX-1, Oak Ridge TN | None yet; building construction began Nov 2025, interior buildout and equipment installation underway as of Aug 2026 (TRISO-X) | NRC license SNM-7007 issued Feb 13, 2026, 40 years; first Category II fabrication license (Federal Register) | ~5 tU/yr (~700,000 pebbles), stated as enough for up to 11 Xe-100 reloads (DOE) | Xe-100 projects; HALEU feed contracted from Centrus Aug 2026 |
| Standard Nuclear | Oak Ridge TN (ex-USNC assets) | Producing HALEU TRISO at pilot scale (~500 kg/yr line); first HALEU feedstock received from DOE's Savannah River Site Jan 2026 (NEI) | DOE-overseen operations; bought USNC's fuel business at auction for $28M | Expansion toward >2 t by mid-2026 on a $140M Series A; two additional facilities planned (ANS) | Radiant (Kaleidos microreactor); DOE allocation recipient |
| Kairos Power | Albuquerque NM / Oak Ridge TN | In-house pilot pebble production for the Hermes demonstration reactors (ANS) | Demo-scale fuel development | Commercial volumes via the BWXT partnership rather than a solo plant | Its own KP-FHR fleet, incl. the Google-backed program |
Companies can hold several roles at once: X-energy designs the Xe-100 and owns its fuel maker; Kairos designs the reactor, makes pilot fuel and buys commercial capacity from BWXT.
Qualification, licensing and plant operation are different gates
The TRISO-X case is the cleanest illustration of why a single announcement never equals fuel:
- Fuel qualification is evidence that the fuel performs under irradiation. DOE's Advanced Gas Reactor program spent years irradiating and testing TRISO variants; that record is what the current designs build on (DOE).
- A facility license is the NRC's permission to possess material and run a plant. TRISO-X's SNM-7007 (February 2026) authorizes activities; it does not build the building. The NRC page for the docket lagged the issuance for a while, a reminder to date claims to the issued document, not a landing page (NRC docket).
- Construction and commissioning turn permission into a working line. TRISO-X began vertical construction in November 2025 and moved to interior buildout in August 2026; output starts after commissioning, not at licensing.
- Sustained production is the only stage that supplies reactors. BWXT is the one US maker that has demonstrated it end to end, most recently with the Pele core.
New fuel forms and higher enrichment can also require license amendments at existing plants (NRC, fabrication of new fuels), and a new plant's own gates are laid out in the NRC's fuel-facility licensing process (NRC).
Reactor customers and fuel compatibility
TRISO capacity is not interchangeable across reactors. A pebble plant makes pebbles to one design's specification: TRISO-X's line is built around the Xe-100 pebble, Kairos pebbles are annular and sized for FLiBe circulation, and Pele's fuel is compacts for a prism core. A qualified line serves the customer it qualified for, and adding a second fuel geometry is a new engineering and licensing exercise, not a production-schedule change. That is why each manufacturer row above lists named customers rather than a generic market: as of September 2026 every US TRISO line is effectively paired with specific reactor programs.
Which reactors need TRISO at all is covered in our design-by-design fuel comparison: the gas-cooled Xe-100, salt-cooled Kairos and heat-pipe eVinci do; sodium fast reactors (Natrium, Aurora) use metal fuel instead, and light-water SMRs use conventional assemblies.
What capacity announcements do and do not establish
Applying the table's columns to the headlines:
- TRISO-X's "5 tonnes per year" is planned capacity for a plant under construction. The demonstrated column is empty until commissioning ends.
- Standard Nuclear's "500 kg/yr, expanding past 2 tonnes" mixes a running pilot line (demonstrated, small) with an expansion plan (funded, unbuilt). Its January 2026 Savannah River feedstock delivery is evidence the pilot line has material to work with.
- BWXT's Pele delivery is demonstrated output, but for a 1.5 MWth military demonstration core; commercial-scale volumes for Kairos remain to be shown.
The reactor milestone tracker follows the demand side of these pairings; the enrichment guide covers where the HALEU feedstock comes from.
The conventional comparison
The existing light-water fuel industry shows what a mature fabrication sector looks like: Westinghouse (Columbia, SC), Framatome (Richland, WA) and Global Nuclear Fuel (Wilmington, NC) each run large licensed plants producing thousands of assemblies a year on qualified, decades-old product lines. TRISO manufacturing in 2026 is at the opposite end: one proven government-scale supplier, one licensed plant under construction, one pilot line and one partnership. Investors reading "TRISO demand" into a fabrication company's revenue should check which of those stages the company is at, using its filings on our SEC filings tracker.
Frequently asked questions
Who manufactures TRISO fuel? In the US: BWXT (the only supplier with sustained deliveries, including the Project Pele core in November 2025), TRISO-X (X-energy's subsidiary, licensed February 2026 and building its Oak Ridge plant), Standard Nuclear (pilot-scale production on former USNC assets), and Kairos Power (pilot pebbles in-house, commercial volumes planned with BWXT).
What is TRISO fuel made of? A sub-millimeter uranium kernel coated in four layers: a porous carbon buffer, inner pyrolytic carbon, silicon carbide and outer pyrolytic carbon. The coated particles are pressed into graphite pebbles or compacts depending on the reactor design. The silicon carbide layer is the main fission-product containment.
Is TRISO fuel commercially available today? At small scale. BWXT delivers TRISO for government programs, and Standard Nuclear runs a ~500 kg/yr pilot line. The first commercial-scale plant, TRISO-X's TX-1, holds its NRC license and is under construction, with a planned ~5 tU/yr output once commissioned.
Does a TRISO fuel license mean the fuel is being produced? No. TRISO-X's February 2026 license authorizes the activity; the plant still has to be built, commissioned and ramped. Qualification, licensing, construction and sustained production are four separate gates, and only the last one delivers fuel.
Which reactors use TRISO fuel? Among named US designs: X-energy's Xe-100 (pebbles), Kairos's Hermes and KP-FHR (pebbles in salt coolant), Westinghouse's eVinci (compacts in a monolith) and the DoD's Project Pele microreactor (compacts). Sodium fast reactors and light-water SMRs use other fuel forms.
This article is for informational purposes only, not investment advice.