Radiant Nuclear
Doug Bernauer
Data verified as of Sep 18, 2026
Summary
Radiant Nuclear (Radiant Industries Inc.) is an El Segundo-based startup founded in 2020 by former SpaceX engineer Doug Bernauer to mass-produce portable nuclear microreactors that replace diesel generators. Its Kaleidos product is a 1 MWe (about 3 MWth per the NRC) helium-cooled, TRISO-fueled high-temperature gas reactor packaged in a single shipping container, air-cooled with no on-site water, designed to run five years between factory refueling and 20 years overall. The Kaleidos Development Unit left El Segundo by truck on August 12, 2026 for a five-phase full-power campaign at Idaho National Laboratory's DOME test bed, where Standard Nuclear-fabricated TRISO fuel has been on site since July 1; as of September 18 the company had not announced criticality. Radiant raised more than $300M in a December 2025 Series D led by Draper Associates and Boost VC at a $1.8B valuation, plus an undisclosed Lockheed Martin Ventures add-on in February 2026, on top of a $165M Series C. On August 26, 2026 the Army and DIU awarded Radiant up to $750M - the largest Janus award - to develop and deploy 15 Kaleidos units, with Fort Benning as the named site and 2030 as the deployment horizon. The Air Force selected it in April 2026 to deliver reactors to Buckley Space Force Base by 2028, and Equinix has a deposit-backed agreement for 20 units. Radiant is building the R-50 fueling and manufacturing campus on a former Manhattan Project site in Oak Ridge, Tennessee; the NRC accepted its 10 CFR Part 70 special-nuclear-material application on May 1, 2026 and has scheduled a license decision by December 18, 2026.
Main Products
A 1 MWe portable high-temperature gas-cooled microreactor using TRISO fuel, helium coolant, and prismatic graphite blocks with zirconium-hydride moderator, packaged in a single shipping container with power conversion and air cooling. Designed to be trucked, shipped, or flown to a prepared pad, reach full power the next day, run five years before factory refueling, and last 20 years (four cores). No on-site water and no on-site spent-fuel storage.
First commercial deliveries are targeted for 2028 (Buckley Space Force Base under ANPI). Equinix has ordered 20 units with deposits. The Army Janus award covers 15 units through 2030. The design is in NRC pre-application (docket 99902106); no commercial operating license has been issued.
The first full-scale Kaleidos article, the same design, size, and commercial fuel load intended for customers, built in El Segundo and shipped by trailer to INL's DOME facility for a five-phase campaign: install and fuel, zero-power criticality, 1 MW thermal, full-temperature/full-power operation, and a minimum 150-hour unattended run.
Left El Segundo on August 12, 2026. TRISO fuel fabricated by Standard Nuclear has been at DOME since July 1. Radiant targeted completing the campaign in Q3 2026. As of September 18, 2026 it had not announced criticality or any later phase. DOE awarded Radiant exclusive DOME access for a full year.
What's Next
Complete the DOME five-phase test campaign
After installation and fueling at INL's DOME, progress through zero-power criticality, 1 MW thermal, full-power/full-temperature operation, and a minimum 150-hour unattended run. Radiant targeted completing that campaign in Q3 2026. As of September 18, 2026 no criticality announcement had been published, so the Q3 window is tight and may slip into Q4.
Win the R-50 Part 70 special-nuclear-material license
The NRC accepted Radiant's 10 CFR Part 70 application for the Oak Ridge fueling building on May 1, 2026 and, in a July 27 Federal Register notice, dated its license determination to December 18, 2026. Radiant has said it is targeting commissioning of R-50 in January 2027. A Part 70 license is for possessing and loading fuel, not a commercial reactor operating license.
Deliver the first Kaleidos to Buckley Space Force Base
ANPI selection on April 22, 2026 names Buckley SFB in Aurora, Colorado as the proposed site, with first Kaleidos reactors targeted for 2028. Siting and NEPA analysis have not finished. Radiant frames this as America's first commercially developed microreactor at a military installation.
File a Kaleidos operating-license application
Radiant's regulatory engagement plan says it will submit an operating-license application for Kaleidos at R-50 in Q4 2026, separate from the Part 70 materials license now under review. NRC pre-application (docket 99902106) has been open since October 2022. As of September 18, 2026 no operating-license application was on file.
Operations & Revenue
The Kaleidos Development Unit was shipped from El Segundo toward INL's DOME facility on August 12, 2026 for a five-phase full-power test campaign. TRISO fuel has been on site at DOME since July 1. As of September 18, 2026 Radiant had not announced zero-power criticality, 1 MW thermal operation, or the 150-hour unattended run, all of which the company had targeted to complete in Q3 2026. No commercial Kaleidos is operating. R-50 construction in Oak Ridge is underway; the NRC Part 70 license that would let Radiant load fuel there has not been issued.
Pipeline & Contracts
Military microreactor deployments (contracted / planned)
Up to $750M Janus agreement with the Army and DIU for 15 Kaleidos units, with Fort Benning as the named site and deployments framed through 2030. Separate ANPI selection to develop and operate reactors at Buckley Space Force Base, with first deliveries targeted for 2028. Both are development-and-deployment programs, not yet operating plants.
Commercial Kaleidos sales (planned)
Factory-built 1 MWe portable reactors sold or contracted to data centers, remote industry, hospitals, and off-grid sites. Equinix has a deposit-backed agreement for 20 units. Radiant says it will fuel, refuel, and store spent fuel at its own facilities so customer sites never hold spent fuel.
Key Metrics
Timeline
On February 9, 2026 DOE approves Radiant's DOE Authorization Request for Kaleidos, meeting the intent of a Preliminary Documented Safety Analysis for a full-power DOME test. On February 17 Lockheed Martin Ventures joins the oversubscribed round as a strategic investor (amount undisclosed).
On April 22, 2026 the Department of the Air Force and DIU select Radiant to develop and operate Kaleidos reactors proposed for Buckley Space Force Base in Aurora, Colorado, with first deliveries targeted for 2028. Next steps include NEPA siting and environmental analysis.
On May 1, 2026 the NRC accepts Radiant's 10 CFR Part 70 special-nuclear-material license application for the Oak Ridge R-50 fueling building for detailed review, aiming to finish about 55% faster than the standard schedule. A Federal Register notice later dates the staff's license determination to December 18, 2026.
On July 1, 2026 Standard Nuclear-fabricated TRISO fuel arrives at INL's DOME facility. On August 12 the Kaleidos Development Unit leaves El Segundo on a trailer for the more than 1,000-mile road trip to DOME, where Radiant plans a five-phase campaign through zero-power criticality, 1 MW thermal, full power, and a 150-hour unattended run.
On August 26, 2026 the Army and DIU execute a binding agreement totaling up to $750M for Radiant to develop and deploy 15 Kaleidos reactors under Janus - Radiant says it is the largest award in the program and one of DIU's largest contracts. The named site is Fort Benning, Georgia; deployments are framed through 2030. The Army's broader Janus awards total up to $2.2B across five vendors.
On August 20, 2026 Radiant signs a long-term TRISO fabrication agreement with Standard Nuclear through the early 2030s. On September 9 it signs a definitive multi-year HALEU supply contract with Centrus, with deliveries before the end of the decade and prepayments to support Piketon expansion, adding a U.S.-origin unobligated enrichment path for national-security deployments.
Radiant announces a $100M Series C in November 2024 led by DCVC and closes the round at $165M on May 28, 2025 with Giant Ventures, StepStone, ARK Venture Fund, and others, taking disclosed venture funding to about $225M. In June it hires former Assistant Secretary for Nuclear Energy Rita Baranwal as chief nuclear officer.
On July 2, 2025 DOE selects Radiant as the first new reactor design to be tested in DOME. On August 8 it signs what it calls the first agreement designed to deliver a mass-manufactured nuclear microreactor to a U.S. military base, with DIU and the Department of the Air Force under ANPI.
After dropping a Bar Nunn, Wyoming factory plan over spent-fuel storage politics, Radiant announces on October 13, 2025 that it will build R-50 on former K-27/K-29 Manhattan Project land in Oak Ridge, Tennessee, a ~$280M investment aiming at 50 Kaleidos units a year after 2028 production starts.
On December 17, 2025 Radiant raises more than $300M led by Draper Associates and Boost VC, with Founders Fund, ARK Venture Fund, Chevron Technology Ventures, and others, at a valuation of more than $1.8B. The company says Equinix has signed a deposit-backed deal for 20 Kaleidos reactors.
Former SpaceX avionics engineer Doug Bernauer founds Radiant in El Segundo with colleagues including Bob Urberger, after looking for a way to power a Mars base and finding no portable terrestrial reactor to buy. The company raises $1.2M from angel investors the same year.
Funding
Cumulative disclosed raise · dated rounds
