Antares Nuclear raises $470M for US military microreactors
In brief
- Antares Nuclear raised $470 million for microreactor development targeting US military bases
- R1 microreactor generates 100 kWe–1 MWe and operates over six years without refueling
- Antares achieved criticality at Idaho National Laboratory on June 4, 2026, first private advanced reactor milestone
- Production targets ten units annually with 2028 deployment timeline
Achieving Criticality
Antares achieved criticality at the Idaho National Laboratory on June 4, 2026, under the Department of Energy's Reactor Pilot Program. The milestone made Antares the first privately developed advanced reactor to reach criticality under the DOE program—a significant validation of the company's technology and approach.
The startup has already secured relationships with major government entities. Antares has partnerships with the US Department of Defense, Department of Energy, NASA, and military branches including the Air Force and Space Force. In September 2024, the company received $3.75 million in Department of Defense funding.
Funding and Production Timeline
Antares closed a $96 million Series B funding round in December 2025, which included $71 million in equity led by Shine Capital and $25 million in debt. The company also raised $30 million in a Series A round in 2024. These rounds bring total capital to $470 million.
The company operates a vertically integrated facility in Torrance, California, and has set production targets of ten units per year. Antares is targeting electricity generation by 2027 and initial deployments by 2028—an aggressive timeline that reflects the Pentagon's urgency around decentralized energy for military operations.
The R1's long refueling interval and compact design make it well-suited for remote bases where resupply logistics are difficult. Energy independence from traditional fuel chains reduces operational vulnerability and strengthens strategic readiness.
