Kairos Power: $629M DOE Deal, No Public Valuation Yet

Kairos Power has never disclosed an equity valuation. What it has is the first construction permit the NRC has ever issued to an advanced reactor, a $629 million DOE-backed demonstration project, and a 500-megawatt power deal with Google — which is a better predictor of where the company is headed than any number a pitch deck could put on it.

Kairos Power is a private, Alameda, California-based nuclear startup building a fluoride salt-cooled reactor design in Oak Ridge, Tennessee, backed by a novel milestone-based funding structure with the Department of Energy. Unlike Oklo, which trades publicly and reports quarterly financials, Kairos hasn't published a priced venture round or a stated valuation — so the honest way to size the company is by what it has actually built, permitted, and contracted for, not by a number nobody has confirmed.

Why Kairos Power Doesn't Have a Public Valuation

Kairos Power is still a privately held company, and as of August 2026 it has not announced a priced venture round with a disclosed post-money valuation — a contrast to nuclear-for-AI peers like Valar Atomics, which put a specific $6 billion figure on its Series B. Public trackers of private-company funding show limited data on Kairos's investor list and cumulative private capital raised, which likely reflects a deliberate choice by the company to let its DOE partnership and hyperscaler deals speak instead of a headline number aimed at press coverage.

What's verifiable instead is the financial structure of its flagship government partnership: Kairos was awarded a Risk Reduction project under the DOE's Advanced Reactor Demonstration Program with a total project value of $629 million, where the DOE contributes $303 million through a Technology Investment Agreement and Kairos matches the remainder with private capital. That's a real, disclosed dollar figure — just not a company valuation. Track how other private nuclear developers are pricing similarly on our Nuclear & SMR Tracker.

The Technology: Why Molten Salt Instead of Water

Kairos builds a fluoride salt-cooled high-temperature reactor (KP-FHR), which combines TRISO pebble fuel — the same tristructural-isotropic particle fuel used in several other advanced-reactor designs — with Flibe, a molten salt coolant made from lithium fluoride and beryllium fluoride that was first proven at Oak Ridge National Laboratory's Molten Salt Reactor Experiment in the 1960s. Fission heats the TRISO pebbles, Flibe carries that heat through an intermediate salt loop, and the loop heats water into steam that spins a conventional turbine.

The practical advantage over traditional light-water reactors is pressure. Flibe operates at roughly 1,200°F but at near-atmospheric pressure, so Kairos's design avoids the thick, high-pressure containment vessels water-cooled reactors require to keep coolant from flashing to steam under an accident scenario. Lower design pressure means simpler containment engineering, which Kairos argues translates into faster construction and lower capital cost per plant — the same cost-reduction thesis behind most of the current advanced-reactor wave, from TerraPower's sodium-cooled design to Oklo's liquid-metal Aurora.

Hermes: The First Advanced Reactor With an NRC Construction Permit

Kairos's demonstration facility, Hermes, is a 35-megawatt-thermal, non-power test reactor in Oak Ridge, Tennessee. In December 2023, it became the first advanced reactor design in U.S. history to receive a construction permit from the Nuclear Regulatory Commission — a genuine regulatory first, not marketing language. Construction began July 30, 2024, and the company is targeting operations in 2027.

The follow-on, Hermes 2, is the power-producing version that actually feeds the Google deal. It received its NRC construction permit in November 2024, broke ground in April 2026, and is targeted to begin operations by 2030. Under the terms of the Google/TVA arrangement, Kairos agreed to increase Hermes 2's single-reactor output from an originally planned 28 megawatts to 50 megawatts to accelerate how much clean power reaches Google's data centers in Tennessee and Alabama.

The Google Deal: Nuclear Power as a Data Center Input

In October 2024, Kairos Power and Google signed a Master Plant Development Agreement — the first corporate agreement of its kind to purchase power from multiple small modular reactors developed by a single company. The structure creates a path for Kairos to develop, build, and operate a U.S. fleet of advanced reactor plants totaling up to 500 megawatts by 2035, selling the energy, ancillary services, and environmental attributes to Google under individual power purchase agreements as each plant comes online, with the first deployment targeted for 2030.

The Tennessee piece of that fleet is now concrete: a PPA between Kairos and the Tennessee Valley Authority routes up to 50 megawatts from Hermes 2 directly onto the TVA grid, which supplies Google's data centers in Tennessee and Alabama. TVA's CEO framed the deal explicitly around U.S. competitiveness in AI, language that echoes how Oklo's Meta agreement is being pitched — nuclear power positioned not as an environmental initiative but as critical AI infrastructure.

Kairos Power vs. Oklo: Private vs. Public Nuclear-for-AI

Figures from company, DOE, NRC, and Google press releases, 2023-2026. Kairos Power financial details are limited to publicly disclosed government and corporate agreements.

The Bottom Line

Bottom line: Kairos Power hasn't put a number on itself, and neither should we. What's verifiable is that it holds the first construction permit the NRC has ever issued to an advanced reactor, a $629 million DOE-backed demonstration project with $303 million in government funding, and a 500-megawatt power agreement with Google that's already converting into a real plant in Oak Ridge, Tennessee. That combination — regulatory precedent, government cost-sharing, and a signed hyperscaler offtake — is a stronger signal of where the company is headed than a private valuation figure would be, and it's the same trio of signals worth checking for any other pre-IPO nuclear startup on our Nuclear & SMR Tracker.