ENMG Analysis
Centrus Will Supply HALEU for Radiant’s Kaleidos Microreactors
The agreement signed September 9 between Centrus Energy and Radiant connects a domestic HALEU supplier with a planned fleet of transportable microreactors, addressing one of the most immediate constraints facing advanced nuclear deployment. Under the definitive multi-year contract, Centrus will supply HALEU fuel for multiple Radiant Kaleidos units, with deliveries scheduled to begin before the end of the decade.
Centrus and Radiant announced that the agreement includes prepayments from Radiant to support Centrus’ domestic commercial enrichment capacity program. The companies did not disclose the contract’s total fuel volume, value, or a guaranteed number of reactors. Those omissions matter because the commercial significance of the agreement is clear, while the precise scale and timing of the resulting fuel deliveries remain subject to future milestone
Why the agreement matters
HALEU, or high-assay low-enriched uranium, is uranium enriched between 5% and 20% uranium-235. That range is above the enrichment level used by most current commercial light-water reactors and is required by many advanced reactor designs to achieve smaller cores, longer operating cycles, or different fuel and power configurations.
The United States has been rebuilding domestic HALEU production after years in which commercial availability was extremely limited. World Nuclear News reported that Centrus is the only NRC-licensed HALEU producer in the United States. The company operates a demonstration cascade at the American Centrifuge Plant in Piketon, Ohio, where it has produced HALEU under Department of Energy contracts.
The Piketon facility’s DOE-supported operations have established a production rate of roughly 900 kilograms of HALEU uranium hexafluoride per year. That figure represents demonstrated and contracted production capability rather than the output of the larger commercial expansion Centrus is now planning. Centrus has also reported cumulative production of more than 1,900 kilograms under its DOE program.
The company’s ability to move beyond demonstration-scale output will be central to the Radiant agreement. Centrus has a DOE contract valued at $900 million to expand domestic enrichment capacity, with options that could raise the potential value to approximately $1.07 billion. The larger expansion is intended to support both low-enriched uranium and HALEU production, with initial new capacity expected later this decade.
The Centrus DOE HALEU contract and the Piketon supply-chain expansion provide the broader context. The federal program is not simply funding a single reactor supplier. It is attempting to establish a fuel platform that can serve multiple advanced reactor developers, including Radiant and X-energy.
Kaleidos is a small reactor with a specialized fuel requirement
Radiant’s Kaleidos is a high-temperature gas-cooled reactor designed to produce approximately 3 megawatts thermal, or 3 MWth, and around 1 megawatt electric, or 1 MWe. The distinction is important. MWth describes the heat generated by the reactor core, while MWe describes the electricity delivered after the heat is converted through the power system.
The design uses TRISO fuel, helium gas coolant, and prismatic graphite blocks. TRISO fuel consists of coated uranium particles engineered to retain fission products at high temperatures. Helium is used as the coolant because it does not undergo the same chemical reactions as water or many other coolants under reactor operating conditions.
Radiant has designed Kaleidos as a transportable unit contained within a single shipping container. That configuration is intended to support potential use at remote industrial sites, military installations, data centers, and other locations where transmission access or fuel logistics may limit conventional generation options.
The fuel contract therefore supports more than a reactor design. It links fuel enrichment, TRISO fuel fabrication, reactor manufacturing, transportation, licensing, and eventual deployment. A delay in any one of those stages could affect the commercial schedule.
The supply gap remains a system-level constraint
The roughly 900-kilogram annual production rate at Piketon should not be compared directly with a single Kaleidos reactor’s undisclosed fuel inventory. Kaleidos is rated at approximately 3 MWth, substantially smaller than the advanced reactors commonly used in industry-wide HALEU demand estimates. Radiant and Centrus have not publicly stated how much HALEU will be required for each Kaleidos unit or for the fleet covered by the contract.
However, the comparison illustrates the broader supply challenge. Industry and government planning documents have often used approximately 15 to 20 metric tons of HALEU as a rough initial-core estimate for a larger advanced reactor in the few-hundred-megawatt class. That estimate is not a requirement for Kaleidos, and it is not the volume disclosed in the Centrus-Radiant contract. Fuel requirements vary substantially by reactor power, fuel form, enrichment level, operating cycle, and core design.
The relevant point is that 900 kilograms per year is still demonstration-scale output when measured against the potential requirements of a large advanced reactor market. Even if a microreactor requires much less fuel than a larger unit, a fleet of reactors would create recurring demand for enrichment and fuel fabrication capacity.
Centrus’ planned commercial expansion is intended to address that gap. The company has said its first new large-scale HALEU capacity could come online by 2029, while the existing cascade may be operated commercially to address nearer-term customer needs. Those dates are company and program expectations, not guarantees of fuel availability for every planned deployment.
Radiant is building fuel supply alongside the reactor
Radiant Chief Nuclear Officer Rita Baranwal said the company has approached fuel supply and reactor development in parallel.
“You can’t deploy nuclear reactors without fuel, so we have approached our fuel supply the same way we have approached the reactor: build it in parallel, and don’t depend on any single path.”
That strategy reflects a practical feature of the advanced nuclear market. Reactor developers can complete engineering, testing, and licensing work but still face delays if the necessary fuel is unavailable. Fuel producers face the opposite problem because expanding enrichment and fabrication capacity requires capital before a large reactor fleet begins commercial operation.
Radiant’s prepayments help reduce that financing problem for Centrus. The arrangement also gives Centrus another commercial customer as it seeks to expand beyond DOE-supported demonstration output. The financial structure is not a guarantee that the planned capacity will be completed on schedule, but it can help align customer demand with investment in production infrastructure.
In August, Centrus signed a separate definitive LEU and HALEU supply agreement with X-energy. That contract is intended to support X-energy’s initial Xe-100 small modular reactors and TRISO-X fuel deployments. Together, the Radiant and X-energy agreements show how advanced reactor developers are attempting to secure fuel before their commercial fleets are fully deployed..
Who benefits and what remains uncertain
Centrus benefits from a growing customer base for domestic enrichment services and from prepayments that support its commercial capacity program. Radiant gains a defined domestic fuel pathway that can be used for commercial and potential national security applications. Because Centrus’ enrichment technology and manufacturing supply chain are U.S.-origin, the resulting fuel can be classified as “unobligated,” allowing use in national security programs subject to applicable authorization and regulatory requirements.
Potential end users could benefit if Kaleidos reaches commercial operation. Remote industrial facilities, defense sites, and data centers are seeking reliable power sources that can reduce dependence on diesel deliveries, constrained transmission networks, or local fossil-fuel generation. A transportable microreactor could also provide high-temperature heat for certain industrial applications, although those uses would require additional project-specific engineering and regulatory approval.
The tradeoffs are equally important. HALEU supply is only one constraint. Radiant must continue progressing through licensing, fuel qualification, manufacturing readiness, testing, and deployment planning. Customers will also compare microreactor costs with natural gas generation, grid connections, batteries, renewable power paired with storage, and other firm-power options.
The contract does not establish that Kaleidos will be commercially deployed by a specific date. It establishes a fuel relationship with deliveries planned before 2030. The difference between a planned delivery window and an operating reactor fleet should remain clear.
What to watch next
The next milestones will determine whether the agreement develops into a reliable commercial fuel pathway.
First, readers should watch for additional information about the contract’s fuel quantities, delivery schedule, and relationship to Radiant’s planned test and deployment program. Second, Centrus’ ability to transition the existing Piketon cascade into commercial operation will be important before larger expansion capacity becomes available. Third, the DOE-funded commercial enrichment program will need to meet construction, licensing, manufacturing, and production milestones.
The broader market will also be watching whether multiple advanced reactor developers can secure fuel without competing for the same limited early HALEU volumes. The Radiant and X-energy agreements may strengthen the case for domestic enrichment investment, but they also underscore how quickly demand could outpace current production if reactor deployments accelerate.
Amir Vexler, Centrus President and CEO, described the agreement as another step toward building a domestic fuel supply network for next-generation nuclear technologies. That is a reasonable description of what has been signed. The larger question is whether the United States can scale enrichment, conversion, fuel fabrication, and reactor manufacturing at a pace that matches the commercial ambitions now being announced.
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