About this Abstract |
| Meeting |
2026 TMS Annual Meeting & Exhibition
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| Symposium
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Solid-State Processing and Manufacturing for Nuclear Applications: Integrating Insights and Innovations
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| Presentation Title |
Friction Stir for Nuclear Fusion: Adapting FSW for Thick Section Dissimilar Copper Joints With Varying Base Material Properties |
| Author(s) |
Michael Eff, Rafael Giorjao, Dang Cai |
| On-Site Speaker (Planned) |
Michael Eff |
| Abstract Scope |
The National Spherical Torus Experiment Upgrade (NSTX-U), led by Princeton Plasma Physics Laboratory, is a magnetic confinement fusion device requiring thick copper bus bars to generate strong magnetic fields. These toroidal field (TF) conductors are made by joining 6-meter Class 1 copper extrusions to Class 2 copper flags, forming 34.7-mm thick dissimilar joints. Traditional fusion welding is unsuitable, prompting the use of friction stir welding (FSW). EWI and PPPL collaborated to address challenges posed by material property variations—up to ±20% in copper lengths and ±14% in flag hardness—caused by differing cold work levels. These inconsistencies affected weldability and process forces. Adaptive strategies using force and position feedback were implemented to accommodate these variations in real time, enabling successful fabrication of the TF conductors.
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| Proceedings Inclusion? |
Planned: |
| Keywords |
Joining, Nuclear Materials, Copper / Nickel / Cobalt |