Kairos Power Completes Phase 1 of ETU 3 Hardware Demonstration in the U.S.

On September 4, Kairos Power announced the completion of Phase 1 of the Engineering Test Unit 3 (ETU 3) hardware demonstration at its Oak Ridge, Tennessee site. The unit, a non-nuclear engineering test platform, is primarily designed to reduce technical risks in reactor construction, operation, and maintenance, and to provide validation data for the Hermes 2 demonstration plant and subsequent commercial reactor deployments.

Kairos Power stated that Phase 1 of ETU 3 focused on design validation of precast concrete shielding structures and testing of remote operation and maintenance capabilities. Construction of the Hermes 2 demonstration plant began earlier this year in Oak Ridge, and experience gained from ETU 3 will support the subsequent deployment of that project.

During this phase of the demonstration, Kairos Power's construction, manufacturing, and engineering teams, together with partners, erected a scaled model of the Hermes 2 reactor cavity. The model was used to test the modular shielding design and remote maintenance approach for the fluoride salt-cooled high-temperature reactor (KP-FHR). The simulated reactor cavity consists of a reactor pressure vessel and precast concrete shielding structures, supported by a steel frame.

The project team installed 12 modular wall segments encompassing four different designs. These segments feature stepped and sinusoidal joint geometries, designed to minimize radiation leakage risks at the seams. Oak Ridge National Laboratory's (ORNL) Manufacturing Demonstration Facility contributed to the design and production of 3D-printed polymer composite molds used for the precast panels, which were subsequently manufactured by Tindall and installed by Barnard Construction.

Kairos Power's Salt Process Equipment Execution and Delivery (SPEED) team is developing systems for online maintenance using robotic equipment within the reactor cavity, aimed at reducing overall operating costs for future KP-FHR commercial plants. To support the demonstration, each panel was fitted with steel frame openings to test different concrete shielding plug designs, allowing process lines to pass through the shielding structure.

In the remote maintenance tests, a robotic arm was mounted above the reactor cavity to connect and disconnect process lines. The design is intended to eliminate the need for personnel to enter the reactor cavity and to enable maintenance operations without interrupting operations.

Austin Clark, senior engineer at Kairos Power responsible for ETU 3 development, stated that the team and partners accelerated the design, fabrication, and delivery of components and assemblies, advanced manufacturing methods for high-quality shielding structures, and deployed online maintenance solutions. Ed Blandford, co-founder and chief technology officer of Kairos Power, stated that the ETU 3 preliminary demonstration helps validate the interfaces between modular shielding structures and reactor equipment, and test the remote operation tools required for maintenance and component replacement.