Samsung C&T to invest up to $100 million in Kairos Power's reactor for Google

Kairos Power has brought in Samsung C&T to help build a 50-megawatt demonstration reactor for Google, with the Samsung engineering group committing up to $100 million in equity investment and in-kind engineering services. Kairos said $70 million of that is equity.

Samsung C&T has built or helped build roughly a dozen nuclear reactors worldwide. Kairos is currently constructing two reactors in Oak Ridge, Tennessee: Hermes 1, a low-power demonstrator, and Hermes 2, a commercial-scale unit the company expects to begin operating in 2030. The Nuclear Regulatory Commission approved construction in late 2024.

Hermes 2 will use a fluoride salt-cooled design that has been studied for years but never built at commercial scale. Kairos says the coolant's high boiling point keeps pressure low, reducing blowout risk, and the reactor will use TRISO fuel — uranium sealed in ceramic and carbon layers — designed to prevent meltdowns.

Google signed its deal with Kairos in 2024, seeking roughly half a gigawatt of nuclear power by 2035. The arrangement is one of several tying nuclear startups to the surge in electricity demand from AI data centers.