Kairos Power
Mike Laufer
Data verified as of Jul 17, 2026
Summary
Kairos Power is commercializing its fluoride salt-cooled, high-temperature reactor (KP-FHR), which combines TRISO pebble fuel with FLiBe coolant in a compact, low-pressure design. The company runs an iterative, vertically integrated development model centered on Hermes 1, a 35 MWth demonstration reactor under safety-related construction in Oak Ridge, and Hermes 2, an electricity-producing demonstration plant for the TVA grid. In April 2026 Kairos broke ground on Hermes 2 — the first deployment under its Google-backed fleet plan totaling up to 500 MWe by 2035 — while a May 2026 NRC amendment extended Hermes 1's construction-completion deadline to April 2029 (Kairos now expects to finish building the test reactor in 2028). Kairos operates two ISO 9001:2015-certified sites (Alameda and Albuquerque) as it scales toward serial reactor-hardware production, and Hermes 2 is targeted to deliver first grid power around 2030.
Company OverviewRead the long-form profile of Kairos PowerMain Products
35 MWth low-power demonstration reactor validating Kairos Power's KP-FHR design, construction methods, fuel program, and operating approach in Oak Ridge, Tennessee.
Construction permit granted in December 2023 and nuclear safety-related construction began in May 2025. In May 2026 the NRC extended the construction-completion deadline by 28 months to April 30, 2029 after first-of-a-kind site and design delays; Kairos now expects to finish building the reactor in 2028, pushing operation past the original 2027 target.
Commercial-scale demonstration plant that extends the Hermes learning loop into electricity production for the TVA grid and Google-backed demand.
NRC construction permits were issued in November 2024 and Kairos broke ground on the plant on April 17, 2026 — the first deployment under its Google-backed fleet plan. Kairos has re-envisioned Hermes 2 as a single-reactor, up-to-50 MWe plant scheduled to begin operations around 2030.
Kairos Power's modular commercial reactor platform for grid, data center, and industrial users, designed around paired 75 MWe units that scale into larger multi-unit plants.
Commercial fleet architecture is now anchored by Kairos Power's Google agreement, with first deployment targeted for around 2030 and additional projects through 2035.
What's Next
Completing construction, fuel loading, and startup of the Hermes 1 low-power demonstration reactor in Oak Ridge to validate Kairos Power's reactor, fuel, and operating model. After a May 2026 permit amendment, Kairos expects to finish building Hermes 1 in 2028, with the NRC construction-completion deadline now set at April 30, 2029.
Operations & Revenue
Development stage — Hermes 1 safety-related construction began in May 2025, Hermes 2 broke ground in April 2026, and first grid power under the TVA agreement is targeted for 2030. After a May 2026 NRC permit amendment, Kairos now expects to finish building the Hermes 1 test reactor in 2028 (construction-completion deadline April 30, 2029). Kairos has no operating reactors yet.
Pipeline & Contracts
DOE Milestone Contract Support
Performance-based ARDP support of up to $303M for the design, construction, and commissioning of Hermes and related risk-reduction work.
Future Power Purchase Agreements
Kairos plans to sell energy, ancillary services, and environmental attributes under PPAs tied to its Google agreement to develop, build, and operate up to 500 MW of advanced reactors by 2035 (first plant online around 2030), beginning with Hermes 2 delivering up to 50 MW to the TVA grid.
Key Metrics
Timeline
The NRC approves Kairos Power's request to extend the latest date for completing Hermes 1 construction by 28 months, from December 31, 2026 to April 30, 2029. Kairos cited first-of-a-kind site-prep and design work — including removing legacy structures from the test-reactor footprint in coordination with the DOE — and now expects to finish building the Hermes test reactor in 2028.
On June 3, 2026 Kairos Power announced that its Alameda, California manufacturing facility passed an ISO 9001:2015 quality-management audit with zero findings, becoming the company's second ISO-certified site alongside its Manufacturing Development Campus in Albuquerque. The certification formalizes standardized quality processes as Kairos scales toward serial reactor-hardware production for Hermes and the Google-backed fleet.
In July 2025 Kairos installs the 14-foot-tall reactor vessel for its third Engineering Test Unit (ETU 3.0) on its Oak Ridge campus, adjacent to the Hermes sites. The vessel was fabricated in the UK with Cambridge Vacuum Engineering and the University of Sheffield's Advanced Manufacturing Research Centre using electron-beam welding, and the ETU 3.0 building — a test bed for streamlined nuclear construction methods — is being erected around it, with construction targeted for completion in summer 2026.
Launches its iterative Engineering Test Unit (ETU) program — full-scale, electrically heated, non-nuclear prototypes of the Hermes reactor used to validate salt-coolant technology, integration, and construction methods. ETU 1.0 went on to log more than 2,000 hours of pumped-salt operations and produced the company's first high-purity FLiBe coolant.