The Nuclear Regulatory Commission (NRC) has received a construction permit application from Kairos Power requesting permission to build a two-unit Hermes 2 test reactor. NRC says the application for a site next to the company’s existing project in Oak Ridge, Tennessee, is now available for public inspection on the its website.

Kairos filed the application on 14 July providing a preliminary safety analysis report for the facility. Each 35 MWt reactor is the same size as the original test reactor the NRC is currently reviewing. The reactors use molten salt as a coolant and would share a power generation system. Kairos will have to submit a separate application for an operating licence in the future.

The NRC staff is reviewing the application to determine if it is complete and acceptable for processing. If the application is determined to be sufficient, the staff will docket it and start a detailed technical review. The NRC will then publish a notice of opportunity to request an adjudicatory hearing on the application before the NRC’s Atomic Safety and Licensing Board.

Hermes 2 is a non-power stepping stone towards deployment of the Kairos Power FHR (KP-FHR). This is an advanced reactor technology that uses TRISO fuel in pebble form combined with a low-pressure fluoride salt coolant. The technology employs a steam cycle to convert heat from fission into electricity and to complement renewable energy sources. The purpose of Hermes 2 is to further reduce risk on the path to commercialising the KP-FHR technology, demonstrating licensing, construction, operations, training, and decommissioning of a multi-reactor plant to help estimate the cost of the first commercial unit.

The earliest possible start date for construction of Hermes 2 is put at July 2025 with the aim of completing the first unit between July 2027 and December 2027. Construction of the second unit is expected to be completed one year after the first unit. The reactors will have a short operating period of 11 years. Kairos CEO Mike Laufer acknowledges that this is an ambitious plan but believes it is achievable.

"While a few important details must fall into place before we can fully commit to building it, Hermes 2 presents a unique opportunity to accelerate commercial deployment of KP-FHR technology while bringing value to the local community over the long term," he said.

Image: Kairos Power's Hermes 2 test reactor design (courtesy of Kairos Power)