California-based startup Radiant Nuclear (formerly Radiant Industries) has signed a long-term fuel supply agreement with Standard Nuclear to provide with tri-structural Isotropic (TRISO) fuel fabrication to support the deployment of Kaleidos microreactors to government and commercial customers through the early 2030s.
Standard Nuclear said the agreement marks a watershed moment for the advanced nuclear industry, signalling commercial scale demand for TRISO fuel across a growing range of reactor applications. It will supply multiple tonnes of TRISO fuel manufactured to the specifications of Kaleidos to be delivered by 2031.
The Kaleidos microreactor design is a transportable high-temperature gas-cooled reactor (HTGR) using high-assay low-enriched uranium (HALEU) TRISO fuel, helium gas coolant, and prismatic graphite blocks. It has a capacity of 3 MWt or 1 MWe. Each 70-tonne microreactor will fit into a single shipping container. each reactor provides up to five years of power before refuelling and is engineered with a 20-year operating life cycle.
Radiant will manage fuelling, refuelling, and used-fuel storage at its own facilities, allowing customer sites to return to greenfield condition within two years or less after a unit is removed. Customer sites never have onsite used fuel storage.
Kaleidos is currently undergoing a full-scale test campaign at Idaho National Laboratory’s Demonstration of Microreactor Experiments (DOME) facility. Following a competitive selection process, the Department of Energy awarded Radiant exclusive access to the facility for a full year. The campaign includes full-scale, full-power, extended-duration testing using the same reactor design and fuel specifications intended for customer deployments. In July, Radiant received its first tranche of nuclear fuel delivered to DOME. The fuel was fabricated to Radiant’s specifications by Standard Nuclear.
The new agreement strengthens Radiant’s fully owned vertically integrated end-to-end supply chain for Kaleidos production. Alongside its 300,000-square-foot R-50 manufacturing, fuelling, and storage campus, in Oak Ridge, Radiant is securing all critical elements of the supply chain needed to deliver production at the scale necessary to meet customer demand.
Radiant Industries was set up in 2019 by former SpaceX engineers. It has benefitted from significant Department of Energy (DOE) support. In October 2023, Radiant was selected as one of three advanced nuclear energy developers to receive funding totalling $3.9m from DOE for developing and testing microreactor designs using DOME.
In April 2025 Radiant was one of five companies selected by DOE to receive HALEU to meet their near-term fuel needs. The following August, Radiant was one of 10 companies selected to receive support under DOE’s Reactor Pilot Program. The same month, Radiant signed an agreement with the Defense Innovation Unit (DIU) and the Department of the Air Force to deliver a first-of-a-kind (FOAK) microreactor to Buckley Space Force Base in 2028.
Radiant had previously received funding awards from the US Department of War to evaluate the integration of microreactors at the Hill Air Force Base near Salt Lake City in Utah. Also in August 2025, Radiant signed a preorder deal with Equinix, a leader in digital infrastructure, for the supply of 20 reactors to power is data centres.
“Securing the fuel supply chain is a strategic advantage to deploying at scale,” said Tori Shivanandan, President and COO at Radiant. “By executing this TRISO fuel supply agreement for our planned deployments through the early 2030s, we have established a key partnership to support our mission.”
Standard Nuclear is a private company that emerged in 2024 out of the bankruptcy assets of the Ultra Safe Nuclear Corporation (USNC), purchasing its core fuel technologies and production facilities at auction for $28m. The company is supported by national security venture firms such as Decisive Point and Andreessen Horowitz.
Its primary manufacturing campus spans a 36.8-acre parcel situated within the historic Heritage Center Industrial Park (the former Manhattan Project K-25 nuclear site) in Oak Ridge. This specific industrial park has evolved into a private advanced nuclear technology hub. Standard Nuclear shares the immediate area with other prominent next-generation energy firms, including Radiant.
In July, Standard Nuclear announced construction and regulatory approval milestones for two of its upcoming TRISO nuclear fuel production facilities. Construction is substantially complete at its SN-TN plant in Tennessee and SN-ID plant in Idaho, with both facilities also securing approval of their Preliminary Documented Safety Analyses (PDSAs) from DOE.
Standard Nuclear has a running Other Transaction Agreement (OTA) with the DOE. Under this agreement, the company physically processes government-allocated HALEU feedstock into commercial TRISO cores for utility developers such as the fuel delivered to DOME for Radiant.
Standard Nuclear has benefitted from continuing support from DOE, which provides critical regulatory framework, material supply, and project funding. In August 2025, the DOE conditionally selected Standard Nuclear as the first participant in its Fuel Line Pilot Program. Through a unique agreement, DOE directly regulates and reviews commercial fuel production at the Tennessee and Idaho facilities.
The company also collaborates with the INL to streamline its progress through rigorous nuclear facility safety guidelines. DOE committed to allocating HALEU from its own stockpiles to Standard Nuclear to fulfil fuel manufacturing requirements. In January 2026, Standard Nuclear became the first company to physically receive HALEU feedstock under this programme at its Oak Ridge facility.
“Radiant is now deploying truly transportable, safe, and highly advanced microreactors to transform the power paradigm for defence, behind the metre, and elsewhere,” said Kurt Terrani, President and Chief Executive Officer of Standard Nuclear. “By offering our customers short, medium, and long-term supply options, we are providing the flexibility and certainty they need to fuel their reactors and meet the growing demand for advanced nuclear fuel across this market.”
