Qualification of grain oriented, additively manufactured tungsten

2025 Research Campaign, Thrust: FPP Candidate Wall Materials

Purpose of Experiment

This 0.5 day PhD student experiment will be investigating the qualification of tungsten (W) samples produced through Additive Manufacturing (AM) under fusion reactor relevant heat and particle fluxes using DiMES. The samples will vary in grain orientations (dominantly (001) or (111)), geometries (flat and angled) as well as sample orientation parallel (II) and perpendicular (⟂) to build direction. These variations in manufacturing are expected to provide results on their impact on mechanical properties and erosion rates. The generated data will help to advance the Technical Readiness Level (TRL) for AM-W towards potential application in fusion system components. The main challenge with AM-W is to manufacture and reproduce high density (low porosity) W, which has been accomplished in recent years. A key feature of the AM process is the control of grain orientation through tuning of manufacturing parameters. While AM-W has demonstrated promising performance during controlled laboratory testing and initial exposures in DIII-D, further R&D is needed to understand how variations in AM-W sample manufacturing parameters and grain orientation can minimize crack formation under thermal stress. 3.

Experimental Approach

This experiment will expose two ‘identical’ 7-button holders that are equipped with the following samples: AM-W in (001) and (111) with the flat plasma facing surfaces being parallel and perpendicular to the build direction (4 samples). Furthermore, we will add (001) and (111) angled samples for increased perpendicular heat flux (2 samples) and a reference sample of ‘ITER-grade’ rolled W for comparison. One DiMES head will experience a continuous heat load and the other to transient Edge Localized Modes (ELMs) heat loads. Continuous heat flux will be achieved through L-mode whereas transient heat loads will be generated in H-mode with ELMs. To maintain a similar power level between these exposures we will perform the L-mode exposure in reversed-toroidal magnetic field (Bt) direction to increase the LH power threshold, while the H-mode will be performed with normal Bt direction. The strikelines will be swept across the DiMES head to provide similar heat flux to all samples. Reference shot #200083 will be used as the target scenario, which already has radial strikeline sweeps programmed and has been deployed in other FPP Materials Thrust experiments.

See more details, including project leads, at U.S. Department of Energy, Office of Scientific and Technical Information (OSTI).