Kairos Power gets up to $100M from Samsung group to build nuclear reactor for Google

Hermes 2 will be a fluoride salt-cooled high-temperature reactor, a design that has been floated for years but never built at commercial scale. Fluoride salts have high boiling points, which will help keep pressure levels low. That, in turn, will limit the risk of high-pressure blowouts in case of any parts failures. 

Kairos is also using a relatively new form of nuclear fuel known as TRISO, which encapsulates tiny seeds of uranium fuel in layers of ceramic and carbon, which are then loaded into billiard ball-sized spheres. The arrangement is intended to prevent meltdowns.

The startup has about five years to get its first power plant up and running, which is an accelerated but manageable timeline in the nuclear industry. To fulfill the terms of its deal with Google, Kairos will need to move even faster on subsequent reactors, something Samsung C&T might be able to help with.