Antares Raises $470M After Its Micro-Reactor Reaches Criticality

Antares Nuclear closed a $470 million Series C — $370 million equity and $100 million debt, co-led by Paradigm and Caffeinated Capital — taking total funding past $600 million. The round follows its Mark-0 demonstration reactor reaching criticality at Idaho National Laboratory, which is the milestone that separates reactor startups with renderings from reactor startups with neutrons. The target market is compact power for military bases and remote sites, but the subtext is the same constraint squeezing every AI buildout: interconnect queues and grid capacity now gate data centre siting more tightly than capital does.