Hermes – Kairos Application

image of Kairos - Hermes
Who:   Kairos Power LLC
What:   Application for a construction permit for an advanced test reactor
When:   September 29, 2021 (date of application submittal)
Where:   Oak Ridge, Tennessee

On this page:

Project Overview

The staff of the U.S. Nuclear Regulatory Commission (NRC) is currently engaged in review activities of the Hermes construction permit application. Kairos Power LLC, is a U.S. based company developing a fluoride salt cooled high temperature reactor (KP-FHR) using TRISO fuel in pebble form.

Plant Characteristic Description
Reactor Type Low-power test reactor to support development of Kairos Power’s fluoride salt-cooled, high-temperature reactor (KP-FHR) technology.
Containment Type Functional containment implemented principally by the high temperature TRISO particle fuel. The fuel utilizes a carbon matrix coated fuel particle, similar to that developed for high temperature gas-cooled reactors, in a pebble-based fuel element. (See SECY-18-0096 for a description of functional containment.)
Power Level 35 MWth (The test reactor will not produce electricity.)
Fuel Tri-structural Isotropic (TRISO) fuel particles embedded in a carbon matrix pebble. High Assay Low Enriched Uranium (HALEU)

All public documents related to Kairos pre-application activities may be found in ADAMS using the "Advanced Search" tab with a "Document Properties:" selection of Docket Number is equal to 99902069.  All public documents related to the Hermes construction permit application review may be found with a selection of Docket Number is equal to 05007513. For additional detail, see the following related pages:

Key Milestones Completion Date
Actual - A
Target - T
Application Tendered 10/31/2021 - A*
Acceptance Review
Acceptance Review Start 09/29/2021 - A*
Docketing Decision Letter Issued/Acceptance Review Complete 11/29/2021 - A
Review Schedule Established/Schedule Letter Issued to Applicant 12/15/2021 - A
Safety Review
Draft Safety Evaluation – Safety Evaluation sections drafted, and information gaps identified 04/06/2022 - A
Safety Evaluation Completion – Additional information requested and evaluated.  Audits complete.  Safety evaluation sections updated. 11/15/2022 - A
Advanced Safety Evaluation – Safety evaluation sections completed and assembled. 02/13/2023 - A
Safety Evaluation Approval – NRC management and legal review complete. 04/18/2023 - A
ACRS Review of Safety Evaluation – Advisory Committee for Reactor Safeguards (ACRS) meetings and review complete.** 05/16/2023 - A
Final Safety Evaluation – Final Safety Evaluation updated and issued. 06/13/2023 - A
Environmental Review
Environmental Scoping – Scoping activities completed, and Scoping Summary Report issued. 08/01/2022 - A
Initial Draft of DEIS Sections - Environmental Report audit completed; Technical Draft Environmental Impact Statement (DEIS) sections completed with open items on track for resolution. 04/12/2022 - A
Complete DEIS Sections – Early legal review of DEIS sections completed; Open items resolved. 06/17/2022 - A
Finalize DEIS and Related Activities – NRC management and final legal review of the consolidated DEIS and associated correspondence completed.  Publication and issuance activities completed. 09/29/2022 - A
Comment Responses and FEIS – Comment period on the DEIS; staff responses to public comments completed and the Final Environmental Impact Statement (FEIS) prepared. 05/05/2023 - A
Finalize FEIS and Related Activities – NRC management and attorney review of FEIS and associated correspondence completed.  Publication and issuance activities completed. 08/17/2023 - A
Hearing 10/19/2023 - T
Construction Permit Decision TBD

*Safety Preliminary Safety Evaluation Report (PSAR) submitted 9/29/2021. Environmental Report Submitted 10/31/21
**The review team will begin interacting with the ACRS subcommittee as soon as portions of the safety evaluation can be made available to the public. When the advanced safety evaluation is approved by NRC staff managers, it is promptly provided to the ACRS for subcommittee and full committee review and ACRS will write a letter to the staff commenting on the evaluation.

Public Involvement

Date Description
11/16/2022 Public Meeting To Discuss The Draft Environmental Impact Statement For The Kairos Hermes Permit Application
Public Meetings on the Kairos Hermes Preliminary Safety Analysis Report (Discussion of Requests for Additional Information)
03/23/2022 Public Outreach Meeting on the Proposed Kairos Hermes Test Reactor with Designated Period for Receipt of Environmental Scoping Comments
02/09/2022 Public Meeting on the Kairos Hermes Preliminary Safety Analysis Report (Discussion of Quality Assurance, Principal Design Criteria, Materials, and Structural Evaluations)


Contacts for the Kairos Power LLC
Safety Project Manager Matthew Hiser

Samuel Cuadrado de Jesus
Environmental Project Managers Tamsen Dozier

Peyton Doub
Public Affairs Officer Scott Burnell