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HermesKairos Power—HermesKairos Power—HermesKairos Power—

Kairos Power

Fluoride salt-cooled reactor, TRISO pebbles, Hermes

USprivateest. 2016kairospower.com (opens kairospower.com)Checked 25 Sep

The brief

Analyst view
  • Hermes got the first US permit in 50+ years for a reactor not cooled by ordinary water (Dec 2023).
  • Google agreed in October 2024 to buy power from up to 500 MW of Kairos reactors.
  • Builds non-nuclear test units in-house first, learning step by step before the nuclear reactor.
Programs

Kairos Power, one program

Updated 16 Jul 2026
HermesA 35 MW (thermal) test reactor that won't make electricity, proving the salt coolant, pebble fuel and safety systems. Hermes 2, which will make electricity, follows.PilotNextConstruction of HermesUpdated 16 Jul 2026View program →
Research · Proto · Pilot · Deploy · Scaling

Upcoming catalysts

Company-wide
  • 2027Hermes test reactor start-up targetedHermesby ~15 mo
  • 2030Hermes 2 due to begin supplying power to TVA's grid for GoogleHermesby ~51 mo

Peers

Fission · 4

Company & funding

HQ
US
Founded
2016

People

Key people
Primer