ETU 3 – for Engineering Test Unit 3 – at Oak Ridge, Tennessee, is part of Kairos Power’s iterative approach for the development of its fluoride salt-cooled high-temperature reactor (KP-FHR) technology. The reduced-scale non-nuclear mockup cavity consists of a reactor vessel and a precast concrete shielding structure – made from 3D-printed polymer composite forms developed with Oak Ridge National Laboratory’s (ORNL) Manufacturing Demonstration Facility – supported by steel frames.
Each panel in the demonstration includes steel-framed openings to test different concrete shielding plug designs that allow process lines from the reactor to pass through the shielding structure to other areas of the plant. The lines will be connected and disconnected using a remote handling system, to minimise disruption during operations.
Kairos Power broke ground for Hermes 2 on the footprint of the former Oak Ridge Gaseous Diffusion Plant in April. The Hermes Low-Power Demonstration Reactor – Hermes 1 – a scaled demonstration reactor – is also under construction at Oak Ridge. The first non-light-water reactor to be approved for construction by the US Nuclear Regulatory Commission, Hermes 1 will not produce electricity, but will feed lessons learned into Hermes 2.
Kairos Power co-founder and Chief Technology Officer Ed Blandford said the completion of the initial demonstration at ETU 3 is an important step toward establishing a sustainable maintenance concept for the future fleet. “By demonstrating the interfaces between modular shielding structures and reactor equipment, and testing the remote handling tools needed to maintain and replace components, we gain a better understanding of design features that will be standardised in commercial KP-FHR deployments,” he said.
ETU 3 – as its name suggests – is the third engineering test unit in the programme, and will help inform the next iterations of the Hermes 2 reactor cavity design as well as providing a training platform for future operators. ETU 1.0 – a full-scale, electrically heated prototype of the Hermes reactor – carried out more than 2000 hours of pumped salt operations demonstrating the design and integration of key systems, as well as exercising the supply chain and establishing new capabilities, including the production of the high-purity fluoride-lithium-beryllium (FLiBe) salt coolant. It was followed by ETU 2.0, a non-power unit to demonstrate modular construction methods.
