Antares raises funds for microreactor development

December 4, 2025, 7:00AMNuclear News
Image: Antares

Advanced nuclear energy start-up Antares has announced the close of a $96 million Series B funding round, led by Shine Capital with participation from Alt Capital, Caffeinated, FiftyThree Stations, Industrious, and other investors. The round raised $71 million in new equity capital and $25 million in debt for equipment, factory build-out, and uranium procurement.

With operations in Torrance, Calif., Idaho Falls, Idaho, and Aiken, S.C., Antares is working to demonstrate a low-power test reactor before July 4, 2026, and to test its first-of-a-kind electricity-producing demonstration unit in 2027. Production units will be deployed as early as 2028, according to the company. It also said its R1 microreactor will produce between 100 kilowatts and 1 megawatt of electricity.

Quote: “This funding marks a major milestone for Antares,” said CEO Jordan Bramble, “We’re months away from our first reactor demonstration, which will validate our control systems and neutronics models, develop our testing facility, and fabricate our fuel ahead of our upcoming full-scale electricity-producing prototype in 2027. We’ve raised the capital we need to mobilize to provide resilient energy for our partners at the Department of War and NASA.”

History: Founded about two years ago, Antares has raised more than $130 million in funding to date, and its 145,000-square-foot facility in Torrance will be capable of producing 10 units per year, the company noted. Antares also has secured contracts with the U.S. Air Force, U.S. Space Force, NASA, and the Defense Innovation Unit to advance its technology.

Progress: Antares said that over this past summer, it conducted an electrically heated demonstration of its reactor in partnership with NASA at the Marshall Space Flight Center in Huntsville, Ala. In April, the company was selected by the Defense Innovation Unit under the Advanced Nuclear Power for Installations (ANPI) program to provide nuclear power to Department of War installations. In August, the company received an allocation of HALEU fuel feedstock from the Department of Energy and was selected for the DOE’s new Reactor Pilot Program, which creates a fast-track pathway for reactor demonstration and licensing.

In October, the U.S. Army announced the establishment of a program of record for advanced nuclear energy, called Janus, which targets reactors from kilowatt class up to 20 MWe. With this new funding, Antares said it plans to compete to provide the Pentagon with resilient energy for critical assets and infrastructure.

Antares also said plans to make a proposal to NASA’s Fission Surface Power program, which aims to deliver 100 kWe of nuclear power on the lunar surface by 2030.


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