Automated maintenance feasibility testing on the EU DEMO Automated Inspection and Maintenance Test Unit (AIM-TU)

In order to reach commercially-relevant availability, future fusion power plants must minimise the duration of maintenance shutdowns. However, as radiation levels increase, so too will the number of maintenance tasks that must be performed without human access. To meet these conflicting constraints, remote maintenance systems must therefore significantly increase their capabilities, performing tasks faster and in parallel. Unfortunately, the current teleoperation-based maintenance approach is inherently limited in these regards. Automation emerges as a potential solution, having demonstrated dramatic productivity gains in manufacturing across the world. The European DEMO project has begun to explore the feasibility of automated maintenance as a route to meeting the challenging availability targets. To this end, the Automated Inspection and Maintenance Test Unit (AIM-TU) has been designed and constructed, providing a highly versatile test platform able to adapt to evolving R&D programmes. It consists of a modular robot cell equipped with two robot arms mounted on linear rails, interchangeable end-of-arm-tooling, a variety of vision sensors and a fully integrated safety system. The hardware is supported by a modular software architecture, which permits different control input modes and provides a digital twin simulation of the cell for virtual verification and validation of control algorithms. This paper provides an overview of the system's capabilities and reports on the first automated maintenance feasibility tests performed on the cell: automatic replacement of JET reactor tiles and automatic contactless inspection of tile anomalies.