NRC staff tour Kairos Power’s Alameda facility in June 2023. Archive photo; not the Hermes 2 construction site. Photo: U.S. Nuclear Regulatory Commission / Wikimedia Commons, CC BY 2.0. Resized for display; homepage cards use a layout crop. The photograph and its display crop remain available under CC BY 2.0.
INVESTMENT / TECHNOLOGY
Kairos Power has lined up $643 million for its Hermes 2 demonstration reactor in Oak Ridge, Tennessee, Bloomberg reported. The money combines about $368 million from private backers, including GV (Google Ventures) and DCVC, with about $275 million in financing from the U.S. Department of Energy. Samsung C&T agreed in September to provide up to $100 million in investment and in-kind engineering, subject to regulatory approvals, and to join the Hermes 2 construction team. Bloomberg reports that $70 million from Samsung is already included in the $368 million private total; the broader up-to-$100 million agreement must not be added to the $643 million.
Hermes 2 is a grid-connected, 50 MWe demonstration of Kairos Power’s fluoride salt-cooled, high-temperature reactor (KP-FHR). The design combines TRISO coated-particle fuel with a molten fluoride salt coolant. That combination allows operation at high temperature and low pressure. Kairos says the plant is meant to reduce the technical, licensing, manufacturing and construction risks for the full-size commercial plants that would follow.
Keeping the numbers apart
- About $368 million in private capital from backers including GV and DCVC.
- About $275 million in DOE financing.
- Total: $643 million, as reported by Bloomberg, citing Kairos CEO Mike Laufer.
- Samsung C&T: its 21 September 2026 term sheet covers up to $100 million in direct investment and in-kind engineering services, subject to regulatory approvals. Bloomberg reports that $70 million of Samsung investment is included in the private-capital total above. The two figures describe different scopes and must not be added together.
The $643 million is therefore not a private capital raise. More than two-fifths of it is federal financing. Kairos has not disclosed the total expected cost of completing Hermes 2.
Industrial partnership
Under the Samsung C&T agreement, the Korean firm joins Kairos’s integrated engineering, procurement and construction (EPC) team alongside Barnard Construction and other partners. Its work initially focuses on power-generation systems and the balance of plant. Kairos keeps responsibility for the reactor technology and the nuclear island. Adding an experienced large-project builder addresses one of the biggest risks for any first-of-a-kind reactor: delivering it on cost and on schedule.
Where the project stands
The NRC issued construction permits for Hermes 2 in December 2024, the first U.S. permits for a power-producing Generation IV reactor. Kairos broke ground in Oak Ridge in April 2026. The company aims to have Hermes 2 operating in 2030, which is a target, not a milestone achieved. Output from Hermes 2 is to count towards Kairos’s agreement with Google, which aims for up to 500 MW from multiple units by 2035.
The open questions are execution questions: final cost, the construction schedule, fuel supply, and the operating licence that the plant will still need before it can run.
Why it matters
Advanced nuclear is attracting serious private capital, but taking a first-of-a-kind reactor to demonstration still relies heavily on federal support and on experienced industrial partners. The financing mix shows what it currently takes to move a new reactor design from paper to steel.
GNEI significance
GNEI interpretation: this section is analysis, not factual reporting.
GNEI interpretation: the story is not simply “funding”. It shows what mix of private capital, public support and industrial partnership is currently required to move an advanced reactor from development towards demonstration. It also marks where the line between private innovation and government backing actually sits.
Funding report
Bloomberg Law, “Nuclear Startup Kairos Raises $643 Million for Tennessee Project”
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