A robotic additive manufacturing system for in-situ repair of in-vessel tokamak components
This paper presents the development of a multi-degree-of-freedom (DOF) additive manufacturing system for automated in-situ repair of plasma-facing components within tokamak reactors. The system integrates a 3-DOF delta robot and two 6-DOF collaborative robotic arms to address the challenges of maintaining complex in-vessel components. Two case studies are explored: repair and maintenance of tiles and pipework as found in tokamak reactors using fused filament fabrication with polylactic acid. Automated processes, including surface preparation, component identification, and repair using the extrusion method, were implemented and tested. Vibration analysis revealed limitations caused by payload constraints and mechanical rigidity, emphasizing areas for further improvement. Experimental results validate the feasibility of automating in-situ repairs while identifying technology gaps, particularly for applications needing high strength materials such as tungsten alloys in plasma facing components. The findings contribute to enhancing maintenance processes in fusion energy systems.