Nuclear energy start-up Antares has raised $30M in Series A financing to expand its R&D and manufacturing capabilities to support the demonstration of its first microreactor. 

The round was co-led by Alt Cap and existing lead seed investor Caffeinated Capital, with participation from Rogue, Uncommon Capital, Shrug, Banter Capital, Box Group, and Shine Capital. Jack Altman of Alt Cap will be joining the Antares Board of Directors. This round brings Antares total capital raised to date to more than $38M.

Antares focuses on high-value use cases in power-constrained environments that wouldn’t be possible without nuclear power. They are developing resilient fission-based power systems for critical assets for the Department of Defense on earth and in space. Unlike grid-scale reactors, these use cases primarily favor kilowatt-scale systems. This focus on non-commodity energy applications with smaller scale reactors will enable Antares to develop its first deployments on faster timelines with less research and development and capitalization risk. Antares also partners with commercial companies in extractive industries, edge computing, and space power, in turn bringing the benefits of commercial scale back to the DOD.

“America needs to return to iterative development of nuclear reactors through a design, build, and learn approach. Nuclear energy will increase our national security, and the same technology will enable human and industrial expansion into outer space and contribute substantially to industrial decarbonization. This is mission-critical technology, and Antares wants to become America’s industrial base partner for special-purpose microreactors” says Jordan Bramble, CEO of Antares.

The Antares reactor is built for reliability in the field and modularity to enable factory production and scalability. Antares will open an R&D facility in early 2025 to support development of high-temperature heat pipes, thermosiphons, and graphite machining. Their design approach involves rapidly building and testing electrically-heated demonstration units (EDU) to validate their simulations. They are building their first 240-kilowatt thermal EDU, scheduled to turn on by mid-2025.

Their multi-disciplinary team of 23 currently has $4.3M in DOD and DOE contracts supporting the development of controls, heat rejection, and power conversion systems. They are partnered with Idaho National Laboratory and the DOE’s National Reactor Innovation Center to demonstrate their first reactor. Additionally, they’re partnered with Sandia National Laboratories on Brayton Cycle development, Savannah River National Laboratory on deployment & energy resilience, and Oak Ridge National Laboratory through a GAIN voucher supporting independent design verification. They are headquartered in Redondo Beach, CA, and have a growing presence in other states.