Plasma Facing Component Testing of 3D Printed Tungsten

Demand for new and renewable energy sources is rising and meeting it will require power sources that do not yet exist at scale. Nuclear fusion, the reaction that powers the sun and other stars, is among the most promising. Sustaining a continuous fusion reaction depends on components that survive inside the reactor, specifically in the divertor area where Tungsten tiles funnel waste particles and heat away from the plasma.

Although Tungsten is an excellent candidate material due to its high melting temperature and thermal conductivity, combined with low tritium retention and the lowest nuclear activation of the materials available, it is also among the hardest metals to manufacture. Poor machinability and low temperature brittleness make the slotted, pocketed tile geometries costly or impossible to machine and laser powder bed fusion struggles to print Tungsten without cracking.

Electron beam powder bed fusion resolves this by changing the thermal environment in which Tungsten is melted: the process runs under high vacuum, protecting a metal that oxidizes readily at temperature and the electron beam is defocused and rastered across the powder bed to hold it well above Tungsten's ductile-to-brittle transition before and after every melt pass. Material stays ductile throughout the build and the result is near fully dense Tungsten free of microcracking, with the design freedom that divertor tile geometries demand.

In this webinar, Jonathan Buckley from JEOL USA will present results from reactor testing of Electron Beam Powder Bed Fusion divertor tiles, which survived exposure with minimal damage. The manufacturing of these Tungsten divertor tiles, from powder to finished product, will be shown along with details on the testing and results.

This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Fusion Energy Sciences, using the DIII-D National Fusion Facility, a DOE Office of Science user facility, under contracts DE-FC02-04ER54698, DE-AC05–00OR22725 with UT-Battelle LLC, DE-NA0003525 with NTESS under DOE NNSA and DE-AC02-09CH11466.

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