Nuclear startup Kairos Power has selected engineering firm Samsung C&T as its construction partner for a 50-megawatt demonstration reactor intended for Google, with completion targeted by 2030.
Under the agreement, Samsung C&T will acquire an equity stake in Kairos and supply engineering services on an in-kind basis. Together, these contributions are valued at up to $100 million, according to a Monday announcement from Kairos Power. The equity component alone accounts for $70 million of that total, a Kairos spokesperson confirmed to TechCrunch.
Samsung C&T brings extensive experience to the table, having constructed or contributed to approximately a dozen nuclear reactors worldwide.
Kairos is among a growing cohort of nuclear startups capitalizing on rising power demand driven by AI data centers. Google initially partnered with the company in fall 2024, commissioning Kairos to develop nuclear reactors capable of producing roughly half a gigawatt of electricity by 2035.
Kairos is currently constructing two reactors at its Oak Ridge, Tennessee facility. The first, Hermes 1, is a low-power demonstrator designed to help the company refine its commercial design. The second, Hermes 2, represents Kairos’s first commercial-scale reactor. Output from Hermes 2 will constitute the initial 50 megawatts under its agreement with Google.
In November 2024, Kairos received construction approval from the Nuclear Regulatory Commission. The company expects Hermes 2 to become operational by 2030, consistent with the timeline established in its original Google agreement.
Hermes 2 will utilize a fluoride salt-cooled high-temperature reactor design — a concept that has been discussed for years but has yet to be realized at commercial scale. The use of fluoride salts, which have high boiling points, enables lower operating pressures and thereby reduces the risk of high-pressure failures in the event of component malfunctions.
Kairos is also employing TRISO, a relatively advanced nuclear fuel in which tiny uranium seeds are encased in layers of ceramic and carbon before being loaded into billiard ball-sized spheres. This configuration is designed to prevent meltdowns under normal operating conditions.
The startup faces an accelerated but achievable timeline, with roughly five years to bring its first power plant online. Meeting the terms of its Google deal will require Kairos to advance even more rapidly on subsequent reactors — an area where Samsung C&T’s deep nuclear construction expertise could prove instrumental.
