- Antares has raised $470 million in Series C financing for the commercialization of its Mark-0 reactor
- The microreactor reached criticality in a test with Idaho National Laboratory and is expected to be delivered to the Department of War by 2028
- The funding round includes $370 million in equity and $100 million in debt
Antares announced Monday that it has closed a $470 million Series C funding round to advance its transition from a demonstrated nuclear reactor to fielded power systems for military and space customers.
The financing package includes $370 million in equity and $100 million in debt, which Antares CEO and Co-founder Jordan Bramble said will be invested “one-to-one with the taxpayer in bringing this technology to commercial scale.”
What Are the Details of the Nuclear Reactor Being Funded?
The funding round comes weeks after Antares achieved criticality with its Mark-0 reactor at Idaho National Laboratory, marking the first privately developed non-light-water reactor to reach such a status in the United States in more than 40 years. The company said the milestone was met on schedule and validated reactor physics, reactivity control and instrumentation in a full-scale core using TRi-structural ISOtropic fuel.
The round was co-led by Paradigm and Caffeinated Capital, with additional participation from Point72 Ventures, Shine Capital, Industrious Ventures and other investors. The Series C proceeds will fund Antares’ progression toward the Mark-1 electricity-producing reactor in 2027 and initial delivery in 2028 to defense customers, including the U.S. Air Force.
What Is the Significance of the Reactor to the Department of War?
Antares said its microreactors are designed for autonomous, multiyear operation without refueling, an approach the company says is built around sustained operation rather than one-time demonstration. With the reactors, the company aims to address a growing vulnerability facing U.S. military installations, many of which rely on commercial grid infrastructure despite rising demand, extreme weather and potential adversary targeting.
Antares’ development timeline is aligned with Executive Order 14299, which directs the Department of War to begin operating a reactor at a domestic military installation by Sept. 30, 2028.
