Why it matters
Radiant is building Kaleidos, a factory-made 1 MWe portable microreactor aimed at diesel replacement at bases, data centers, and remote sites. On 26 August 2026 the company said the U.S. Army and the Defense Innovation Unit executed a binding Janus agreement totaling up to $750 million to develop and deploy 15 Kaleidos units, which Radiant calls the largest Janus award. Fort Benning public affairs later said the post is paired with Radiant Industries to host three 1 MW units. Those figures are development-and-deployment ceilings and site pairings, not operating plants and not current product revenue.
The first full-scale article left El Segundo in mid-August 2026 for Idaho National Laboratory's DOME test bed. Wikipedia records that shipment, Equinix's 20-unit pre-order, and the Air Force Buckley selection, not a completed fueled test. Radiant matters because it has stacked named military and commercial demand ahead of a public criticality result.
History
Doug Bernauer, a former SpaceX avionics engineer, founded Radiant Industries in El Segundo in 2020 with colleagues including Bob Urberger. Wikipedia traces private funding from a 2020 angel round through a December 2025 Series D of more than $300 million and a 2026 total above $575 million. DOE selected Radiant in 2025 as the first new reactor design for DOME. Standard Nuclear TRISO reached DOME on 1 July 2026, and the Kaleidos Development Unit left El Segundo on 12-13 August 2026 for a more than 1,000-mile road trip. Radiant said the five-phase campaign, through zero-power criticality, 1 MW thermal, full power, and a minimum 150-hour unattended run, was targeted for the third quarter of 2026.
After dropping a Bar Nunn, Wyoming factory plan over spent-fuel storage law, Radiant sited the R-50 plant on former K-27/K-29 land in Oak Ridge, Tennessee, aiming to produce up to 50 reactors a year after 2028 production starts.
Technology and products
The NRC describes Kaleidos as a transportable high-temperature gas-cooled reactor using TRISO fuel, helium coolant, and prismatic graphite blocks, designed for about 3 MWth and approximately 1 MWe, fully contained in a single shipping container. Radiant adds air cooling with no on-site water, a five-year core, a 20-year life, factory refueling, and company-managed spent fuel so customer sites can return to greenfield. The DOME article is presented as the same design, scale, and commercial fuel load intended for customers, not a sub-scale physics mockup.
NRC pre-application on docket 99902106 has been open since October 2022. As of the 15 September 2026 page review, Kaleidos remains in pre-application, the Kaleidos Development Unit commissioning plan is still under review, and no operating-license application is listed. A separate 10 CFR Part 70 special-nuclear-material application for the Oak Ridge R-50 Fueling Building is received and under review.
Business model
Radiant intends to sell or operate factory-built, plug-in units rather than construct site-specific plants. The Janus agreement is for up to 15 units through 2030, with Fort Benning named. Army Fort Benning public affairs, on 10 September 2026, said three 1 MW reactors would provide 3 MW of on-post generation, contractor-owned and operated with Army regulatory oversight, with candidate parcels identified and the final pad still under evaluation. The 15-unit company figure and the three-unit Benning pairing should be kept distinct. The $750 million ceiling is Radiant's disclosure.
Wikipedia records the April 2026 Air Force and DIU selection for Buckley Space Force Base, with first deliveries targeted for 2028, plus Equinix's 20-unit pre-order and later Standard Nuclear and Centrus fuel contracts. Radiant says it will fuel, refuel, and store spent fuel at its own facilities.
Financials
Radiant remains pre-revenue on Kaleidos sales. Wikipedia places cumulative private funding above $575 million as of 2026, including a December 2025 Series D of more than $300 million. Janus is a milestone-based development-and-deployment contract of up to $750 million, not recognized reactor-sales revenue. Radiant's Janus release also describes a 300,000-square-foot Oak Ridge manufacturing, fueling, and storage campus already under construction. The shipment post said R-50 was tracking toward January 2027 commissioning, contingent on the accelerated Part 70 review Radiant said targeted the fourth quarter of 2026.
Competition and constraints
Janus is a five-vendor program. Fort Benning's pairing with Radiant sits alongside other named bases. Wikipedia notes the Army's broader awards total up to $2.2 billion across five vendors, with funding contingent on performance milestones. HALEU supply, NRC licensing, NEPA at Buckley, and an unset Benning pad are parallel constraints.
The third-quarter 2026 DOME window that Radiant published with the August shipment has closed. Wikipedia, read on 7 October 2026, still records the August shipment rather than criticality. The NRC Kaleidos page, last reviewed 15 September 2026, still lists the KDU commissioning plan as under review. Those sources do not support treating Kaleidos as a completed fueled demonstration. Wyoming's spent-fuel storage restriction, which ended the Bar Nunn factory plan, shows materials policy can override siting even after local outreach.
What to watch
The blocking unknown is whether the Kaleidos Development Unit has been installed, fueled, and taken to zero-power criticality at DOME, and whether Radiant has issued a revised five-phase date after the third-quarter 2026 target. Watch for a Kaleidos operating-license filing; the NRC page still shows only pre-application plus the R-50 Part 70 review. First hardware remains targeted for 2028 at Buckley under ANPI, with Janus deployments framed through 2030 and Fort Benning's pad still to be chosen.