A test unit reactor vessel fabricated in partnership with the University of Sheffield Advanced Manufacturing Research Centre (AMRC) and Cambridge Vacuum Engineering (CVE) has been successfully installed by Kairos Power at its USA campus in Tennessee. 

The 14-foot-high reactor vessel is the central component in Kairos Power’s non-nuclear reactor mockup, marking a significant milestone for the US-based nuclear energy company in the construction of its third Engineering Test Unit (ETU 3.0). 

The University of Sheffield AMRC brought its unique expertise and capability to the project, integrating various advanced manufacturing technologies under one roof. The AMRC's capability to manage machining, welding and inspection in a single location allowed for the fabrication of a complete vessel rather than individual parts, proactively addressing potential future issues. 

Ben Morgan, interim CEO at the University of Sheffield AMRC, said: “Large demonstrators like the ETU 3.0 reactor vessel are vital for effectively bringing advanced manufacturing methods into industry, offering a holistic solution for fabricating complex, large-scale components. 

“The collaborative efforts of CVE, Kairos Power and the AMRC in addressing the complexities of welding, fixturing, machining and inspection for ETU 3.0 will undoubtedly accelerate the deployment of advanced nuclear technologies for clean, affordable and secure power."

The ETU 3.0 reactor vessel has been fabricated using cutting-edge electron beam welding technology, which produces high-quality welds at least an order of magnitude faster than conventional arc welding. For example, welds that previously took one week during the fabrication of the ETU 2.0 vessel were completed in approximately ten minutes for ETU 3.0.

CVE's Ebflow local-vacuum electron beam technology was instrumental in this process, offering substantial time and cost savings. Bob Nicolson, CVE managing director, said: "Our collaboration with Kairos Power underscores the transformative potential of electron beam welding in advanced manufacturing.

“The technology scales well to the precise and demanding requirements of nuclear construction, and this partnership represents a significant step forward in SMR commercialisation.”

The ETU 3.0 project allowed Kairos Power to evaluate the use of electron beam welding to enable faster, more cost-effective production of reactor vessels with precise tolerances for its future commercial fleet.

Beyond its manufacturing innovations, the ETU 3.0 facility will serve as a vital proving ground to refine civil construction methods and quality assurance procedures for the Hermes Low-Power Demonstration Reactor, and will ultimately support the Hermes reactor as an operator training centre and test platform for remote handling and maintenance equipment.

Edward Blandford, chief technology officer and co-founder of Kairos Power, said: “The installation of our third  ETU reactor vessel marks a significant moment on our commercial development pathway.

“ETU 3.0 will serve an important mission as a testing and training platform to ensure safe and efficient operations for the Hermes reactor. But, more broadly, the expertise and capabilities we gain from the ETU program will help pave the way to successfully deploy Kairos Power’s commercial fleet.”

The facility will help improve operator safety and reduce downtime by prequalifying procedures for maintaining and replacing high-temperature reactor systems and components. Capabilities to be tested will include shielded component transfer systems, heavy-lifting and positioning systems, and remote vision, control and feedback. 

The ETU 3.0 building will also house a Modular Systems Facility where plant equipment modules for ETU 3.0 and the Hermes reactor will be staged, assembled, and tested prior to installation. The modular reactor construction methods being piloted with the ETU series and Hermes will be foundational to reducing construction costs and timelines for future plant deployments.