TL;DR · 30-second read

The Short Version

Two American companies have agreed to build the fuel supply for a new kind of nuclear reactor, one small enough to be trucked, shipped or flown to wherever power is needed.

Centrus Energy will make the specially enriched uranium that Radiant’s Kaleidos reactors run on. Deliveries start before 2030, and Radiant is paying money up front to help Centrus expand its enrichment plants.

It matters because these reactors are aimed at remote sites, military bases and the power-hungry computer warehouses behind artificial intelligence.

Centrus Energy Corp. and Radiant announced on September 9 a definitive multi-year contract under which Centrus will supply high-assay, low-enriched uranium, or HALEU, for multiple units of Radiant’s Kaleidos transportable microreactor. Centrus said deliveries will begin before the end of the decade, and that the agreement includes prepayments from Radiant that support the build-out of Centrus’s domestic commercial enrichment capacity.

Because Centrus enriches with U.S.-origin technology and a U.S. manufacturing supply chain, the companies said the material supplied to Radiant will be unobligated, meaning it carries no foreign peaceful-use restrictions and can be used for national security applications as well as commercial ones. Neither company disclosed the contract value, the quantity of fuel involved, or the number of reactors it covers.

Executive Summary

The agreement extends a pattern Centrus has been building for two years: converting its position as the sole domestic producer of HALEU under a U.S. Department of Energy program into commercial offtake from advanced reactor developers. It follows a separate LEU and HALEU supply agreement with X-energy and adds Radiant to a backlog that Centrus uses to justify expansion at its Piketon, Ohio, and Oak Ridge, Tennessee, sites.

For Radiant, the logic runs in the opposite direction. Advanced reactor developers have repeatedly found that fuel, not engineering, is the binding constraint on deployment. Kaleidos and most other microreactor and advanced designs require uranium enriched to between roughly 5 and 20 percent uranium-235, well above the 3 to 5 percent that fuels the existing light-water fleet, and until recently there was no meaningful Western commercial supply. Chief Nuclear Officer Rita Baranwal framed the deal as removing one of the biggest constraints facing advanced nuclear deployment, and said Radiant is deliberately pursuing more than one fuel path.

The structure is the most economically interesting part. Prepayments mean a reactor developer is helping to finance an enrichment plant before that plant has produced fuel for it. That is customer capital substituting for project finance in a sector where lenders have historically been reluctant, and it signals conviction on both sides. It also concentrates risk: if either the reactor or the enrichment expansion slips, both parties are exposed.

The Fuel Bottleneck Moves Upstream

For most of the past decade, the advanced nuclear conversation was about reactors. Designs proliferated, regulators built new review pathways, and developers raised capital on the promise of factory-built units. The quiet problem was that almost none of those designs could run on the fuel that commercial enrichment plants actually make. HALEU sat in a gap between civilian fuel and material of proliferation concern, and the only substantial supplier was Russia.

What the Centrus and Radiant contract represents is the bottleneck moving from availability to schedule. The question is no longer whether domestic HALEU will exist, but whether enough of it will exist, at the right time, at a price that lets a microreactor compete with a gas turbine or a grid interconnection. Centrus committing to deliveries before the end of the decade is a real date, though a soft one. It leaves several years of execution risk in a business where centrifuge cascades, licensing and security infrastructure all have long lead times.

The prepayment mechanism also changes the incentive structure across the sector. If reactor developers can be induced to fund enrichment capacity ahead of demand, the classic chicken-and-egg standoff, where no one builds a plant without customers and no one signs customers without a plant, becomes solvable in stages. It is a model worth watching, because it implies that the credible reactor developers are those who can put capital into their own supply chain.

Unobligated Fuel Is the Commercial Differentiator

The most consequential technical claim in the announcement is the least discussed publicly. Uranium enriched using technology derived from foreign sources, or processed under international nuclear cooperation agreements, carries obligations restricting it to peaceful use. Material produced with wholly U.S.-origin technology does not. That distinction determines whether fuel can go into a reactor powering a military installation or a defense-adjacent facility.

Centrus states that its AC100 centrifuge design is the only deployment-ready U.S.-origin technology available for unobligated enrichment today. That is a company characterization of a competitive landscape rather than an independently verified fact, and rivals developing domestic enrichment would be expected to contest the framing over time. It is nonetheless a meaningful position while it holds. Radiant explicitly cites commercial and national security applications for Kaleidos, and defense customers are the segment least sensitive to price and most sensitive to sourcing provenance.

For Centrus, the strategic value is that unobligated capacity is difficult to replicate quickly. Enrichment technology is export-controlled, capital-intensive and slow to license. A supplier with a durable claim to the defense-eligible segment of the market can price differently there than in the contested commercial market, where the release’s own risk disclosures acknowledge significant competition from foreign producers who may be less cost sensitive.

What Data Center Operators Should and Should Not Read Into This

Radiant’s stated markets include data centers, and that is why this announcement matters beyond the nuclear trade press. Transportable microreactors are attractive to operators facing multi-year interconnection queues, the waiting lists utilities maintain for connecting large new loads to the grid, and to those building in locations where transmission simply does not exist.

The honest read is that this is a fuel contract, not a power contract. Nothing announced here commits a reactor to a site, secures a licence for one, or names a data center customer. Radiant is described as moving from its first Kaleidos test toward commercial deployment, which places the technology before commercial operation rather than after it. Operators making 2027 and 2028 capacity decisions cannot plan around Kaleidos, and should treat microreactors as a possible answer to the early 2030s question of how to power sites that the grid cannot reach in time.

What operators can reasonably take from it is directional. Fuel supply has been the standard objection to every microreactor pitch, and each contract of this type weakens that objection a little. The remaining objections, regulatory approval, fuel fabrication, unit economics at low output and the practical politics of siting a reactor next to a commercial building, are unaffected by this agreement.

The Backlog Story and Its Limits

Centrus is presenting the deal to investors as backlog growth, and backlog is the metric the equity story rests on. The company has now layered a microreactor developer on top of prior commitments including its agreement with X-energy, broadening its customer base beyond the government HALEU program that started it.

Backlog quality, however, depends on terms that were not disclosed. A multi-year supply contract can be firm take-or-pay volume or a framework contingent on the customer’s own milestones. Prepayments suggest genuine commitment, but their size relative to the expansion programs at Piketon and Oak Ridge determines whether they are a financing event or a goodwill deposit. Centrus’s own forward-looking statements flag dependence on U.S. government appropriated funding for HALEU, its Piketon lease and successful execution of the planned expansions, which is a fair summary of what has to go right.

The counterparty risk runs both ways and is worth stating plainly. Centrus is taking on a customer whose reactor is not yet commercially deployed, and Radiant is relying on an enrichment expansion that is not yet complete. That is not a criticism of either party so much as a description of what building a new industrial supply chain looks like. It does mean the announcement should be read as an intention backed by capital, not as fuel in a cask.

Background

Centrus Energy Corp., listed on the New York Stock Exchange as LEU and headquartered in Bethesda, Maryland, is the successor to the United States government’s commercial uranium enrichment enterprise. The company says it has supplied more than 1,850 reactor years of fuel to utility customers since 1998, which it equates to more than 7 billion tons of coal. In recent years it has pivoted from a trading and services business toward restoring domestic enrichment capability, producing HALEU at Piketon, Ohio, under a Department of Energy program and pursuing commercial expansion there and at Oak Ridge, Tennessee.

Radiant develops transportable nuclear microreactors under the Kaleidos name, aimed at commercial, industrial and defense customers who need power delivered to a location rather than drawn from a grid. Its market exists because two constraints converged: rising electricity demand from artificial intelligence computing and industrial electrification, and the long queues and transmission limits that slow new grid connections. The sector’s persistent obstacle has been fuel. Advanced designs need HALEU, Western commercial supply barely existed until recently, and the material was long sourced primarily from Russia, making domestic enrichment a national security priority as well as a commercial one.

Sources

Source: Centrus and Radiant Announce Long-Term Partnership for Domestic HALEU to Supply Kaleidos Microreactors, the September 9, 2026 announcement from Centrus Energy Corp. detailing the multi-year HALEU supply contract, the prepayment structure and the unobligated enrichment provision.