Antares Nuclear recently achieved criticality with Mark-0
US advanced nuclear power startup Antares Nuclear has raised $470m (€413m) to build micro nuclear reactors for US military bases.
The company said the Series C round, which was led by adventure capital firms Paradigm and Caffeinated Capital with participation from Industrious Ventures, Point72 Ventures, and Shine Capital, underscores investors' growing interest in advanced nuclear startups – a trend fuelled by an AI data centre building boom and demand for reliable new sources of low-carbon power.
The funding included $370m in equity and $100m in debt.
Antares announced on 4 June that its Mark-0 microreactor achieved initial criticality at Idaho National Laboratory (INL), making Antares the first private company to bring an advanced reactor to criticality under the US Department of Energy’s (DOE) push to deploy advanced plants.
The California-based company said the demonstration, backed by the DOE under its Reactor Pilot Program, meets an ambitious objective set by president Donald Trump and the DOE to reform how the federal government tests advanced reactors, and it establishes a replicable licensing pathway that the DOE and industry can use to accelerate future reactor demonstrations on commercial timelines.
The company is one of three finalists in the Pentagon’s Advanced Nuclear Power for Installations program, which will test SMRs on Air Force bases in Colorado and Montana. Antares aims to bring its first electricity-producing reactor online next year, with deployments at US military installations planned for 2028.
Antares is developing what it calls factory-produced, deployable fission microreactors of up to 1 MW to provide strategic energy for mission-critical systems across Earth, space and underseas.
In December Antares raised $96m in Series B funding as it pursues its reactor design.
