Self-Directed Investors historically have had limited access to private companies like Radiant Industries, Inc. before they go public. All US investors can download the SoFi or Titan app and, with as little as $500, invest in a portfolio of private and public companies through the ARK Venture Fund.
Radiant Industries, Inc. is in the process of developing an advanced nuclear microreactor that provides an alternative to fossil fuels, mainly diesel generators, for both military and commercial applications. The company plans to mass-manufacture Kaleidos, a 1-megawatt-electric high-temperature gas-cooled microreactor that fits inside a standard shipping container and travels by air, sea, or road. The company plans to test the reactor at Idaho National Laboratory's DOME facility in 2026, targeting its first commercial delivery by 2028.
Nuclear energy has long been plagued by cost overruns and delayed projects, but that wasn't always the case. According to ARK's research, prior to regulatory changes in the 1970s, in accordance with Wright’s Law, US nuclear construction costs declined ~20% for every cumulative doubling in power online. Today, regulatory tailwinds are the strongest they've been in decades: the ADVANCE Act, signed in 2024, directs the Nuclear Regulatory Commission to streamline licensing for advanced reactors,1 and four Executive Orders signed in May 2025 aim to revitalize the US nuclear industry. We believe radiant is well-positioned to benefit.
Radiant has consistently executed on its development milestones. In 2020, CEO Doug Bernauer said Radiant would have a microreactor at DOME by 2026—it arrived in August, ahead of testing later this year.2 The U.S. Air Force, working with the Defense Innovation Unit (DIU), selected Radiant to field a microreactor at Buckley Space Force Base, with delivery targeted for 2028.3 In August 2026, Radiant won a $750M contract from the US Army to develop and deploy 15 Kaleidos nuclear microreactors by 2030 through the Army’s Janus Program, one of the largest contracts ever issued by the DIU.4 Commercial demand is emerging alongside the defense signal: Equinix signed a preorder with deposits for 20 Kaleidos units in August 2025 for powering its data centers.5
In December 2025, Radiant raised a Series D of more than $300 million, roughly six months after closing its Series C, with participation from investors, including the ARK Venture Fund.6 The appointment of Dr. Rita Baranwal, a former U.S. Department of Energy Assistant Secretary for Nuclear Energy, as Chief Nuclear Officer adds regulatory and institutional credibility.7
Radiant remains pre-revenue and pre-criticality: a first-of-a-kind reactor carries execution risk, a still-maturing HALEU fuel supply, and manufacturing execution needed for favorable unit economics. Radiant embodies our core investment framework: we look for companies applying disruptive innovation to large, underserved markets, and we give them years—not quarters—for cost declines and exponential adoption to play out.
We hold Radiant in the ARK Venture Fund and discuss our reasoning further in our ARK Venture Q1 2025 update and ARK Venture Q4 2025 update.
Important Information
We offer our view of Radiant because it is part of the total ARK Venture Fund portfolio. To see the most updated portfolio, please visit here. Holdings subject to change. Not a recommendation to buy, sell, or hold any specific security.
BEFORE INVESTING YOU SHOULD CAREFULLY CONSIDER THE FUND'S INVESTMENT OBJECTIVES, RISKS, CHARGES AND EXPENSES. THIS AND OTHER INFORMATION IS IN THE PROSPECTUS, A COPY OF WHICH MAY BE OBTAINED HERE. PLEASE READ THE PROSPECTUS CAREFULLY BEFORE YOU INVEST.
There is no assurance that the Fund will meet its investment objective. The value of your investment in the Fund, as well as the amount of return you receive on your investment in the Fund, may fluctuate significantly. You may lose part or all of your investment in the Fund or your investment may not perform as well as other similar investments. Therefore, you should consider carefully the risks at the bottom of this page before investing in the Fund.
ARK Investment Management LLC is the investment adviser to the ARK Venture Fund.
Foreside Fund Services, LLC, distributor.
U.S. Nuclear Regulatory Commission. 2024. "About the ADVANCE Act." Nuclear Regulatory Commission.
Shivanandan, T. 2026. “@DougBernauer called it in 2020 when he said we'd have a reactor in the DOME in 2026…” X.
Department of the Air Force, Defense Innovation Unit. 2026. "Air Force Selects Radiant to Deliver Microreactors to Buckley Space Force Base." AccessNewswire.
Radiant. 2026. “Radiant Wins $750M Contract from US Army to Deliver Energy Independence to US Military Bases.” Radiant.
World Nuclear News. 2025. "Equinix Signs Further Agreements With SMR Developers." World Nuclear News.
Nuclear Engineering International. 2025. "Radiant Secures Microreactor Funding." NEI Magazine.
ExchangeMonitor. 2025. "Radiant Appoints Rita Baranwal as Its Chief Nuclear Officer." ExchangeMonitor.
ARK’s statements are not an endorsement of any company or a recommendation to buy, sell or hold any security. ARK and its clients as well as its related persons may (but do not necessarily) have financial interests in securities or issuers that are discussed. Certain of the statements contained may be statements of future expectations and other forward-looking statements that are based on ARK’s current views and assumptions and involve known and unknown risks and uncertainties that could cause actual results, performance, or events to differ materially from those expressed or implied in such statements.
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