Kairos
Project Overview
The U.S. Nuclear Regulatory Commission (NRC) is currently engaged in pre-application activities with Kairos Power starting in November 2018. Kairos Power is an Alameda, CA company designing a fluoride salt-cooled high temperature reactor (FHR) using Triso-coated particle fuel in a pebble bed configuration.
For more information, please see the Kairos pre-application documents (NRC Docket 99902069).
To subscribe to the Kairos Fluoride Salt-Cooled High Temperature Reactor (FHR) email service, select Kairos Power FHR from the Advanced Reactors list after entering your email into the GovDelivery system.
For information related to the NRC staff’s review of Kairos’ Hermes testing facility, please see the Hermes review webpage.
For information related to the NRC staff’s review of Kairos’ Hermes 2 testing facility, please see the Hermes 2 review webpage.
Pre-Application Activities
| Product | Type | Reference | Status |
| Principal Design Criteria (PDC) for the Kairos Power Fluoride Salt-Cooled, High Temperature Reactor (KP-TR-003) | Topical Report | ML19212A756 | Feedback Provided ML20167A174 |
| Regulatory Analysis for the Kairos Power Fluoride Salt-Cooled High Temperature Reactor (KP-TR-004) | Topical Report | ML22018A161 | Feedback Provided ML22159A356 |
| Reactor Coolant for the Kairos Power Fluoride Salt-Cooled High Temperature Reactor (KP-TR-005) | Topical Report | ML20016A486 | Feedback Provided ML20219A591 |
| Scaling Methodology for the Kairos Power Testing Program (KP-TR-006) | Topical Report | ML19357A252 | Feedback Provided ML21013A430 |
| KP-FHR Risk-Informed Performance-Based Licensing Basis Development (LMP) Methodology (KP-TR-009) | Topical Report | ML20101P623 | Feedback Provided ML20328A229 |
| KP-FHR Fuel Performance Methodology (KP-TR-010) | Topical Report | ML21162A349 | Feedback Provided ML22125A275 |
| Metallic Materials Qualification, Rev. 4 (KP-TR-013) | Topical Report | ML23102A176 | Feedback Provided ML23102A179 |
| Kairos Quality Assurance Program (KP-TR-007) | Topical Report | ML21117A046 | Feedback Provided ML21350A347 |
| Fuel Qualification Methodology (KP-TR-011) | Topical Report | ML22186A215 | Feedback Provided ML23089A398 |
| KP-FHR Mechanistic Source Term Methodology, Rev. 4 (KP-TR-012) | Topical Report | ML26029A417 | Feedback Provided ML26075E846 |
| Graphite Materials Qualification, Rev. 4 (KP-TR-014-NP) | Topical Report | ML23108A314 | Feedback Provided ML23108A317 |
| Instrument Setpoint Methodology for the Kairos Power Fluoride Salt‐Cooled High Temperature Reactor (KP‐TR‐021‐NP) | Topical Report | ML24102A116 | Feedback Provided ML24102A118 |
| Safeguards Information (SGI) Protection Plan | SGI Plan Approval Request | ML23118A323 | Feedback Provided ML23268A009 |
| KP-FHR Core Design and Analysis Methodology Topical Report (KP-TR-024-NP) | Topical Report | ML24095A255 | Feedback Provided ML25338A331 |
| Safety Analysis Methodology for the Kairos Power Fluoride Salt-Cooled High-Temperature Test Reactor (KP-TR-020-NP) | Topical Report | ML26007A304 | Feedback Provided ML26007A307 |
| Basic Component Definition for the Hermes Non-Power Test Reactors | White Paper | ML24092A389 | Feedback Provided ML24250A124 |
| Hermes 1 Site Characteristics and Geologic Mapping Condition Audit Plan | Audit | ML24222A393 | Under Review |
| Approach to Address Limitations and Conditions Contained within Safety Evaluations for Fuels Topical Reports | Audit | ML25105A030 | Feedback Provided ML26058A464 |
| Operator Training and Testing Program for the Non-Power Kairos Power Fluoride Salt-Cooled High-Temperature Reactors | Topical Report | ML25192A231 | Under Review |
| Kairos Power LLC 10 CFR 55 Exemption Requests for Non-Power Kairos Power Fluoride Salt-Cooled, High Temperature Reactors | Exemption | ML25211A317 | Under Review |
Contacts
| Contacts for the Kairos Power FHR Pre-Application Review | |
|---|---|
| Lead Project Manager | Cayetano Santos |
| Contact a Public Affairs Officer | |
Page Last Reviewed/Updated Monday, April 13, 2026
Page Last Reviewed/Updated Monday, April 13, 2026