Multiscale Materials Modeling of low-energy He plasma surface interactions with Tungsten

Brian Wirth
University of Tennessee

The plasma facing components, first wall and blanket systems of future tokamak-based fusion power plants arguably represent the single greatest materials engineering challenge of all time. Indeed, the United States National Academy of Engineering has recently ranked the quest for fusion as one of the top grand challenges for engineering in the 21st Century. These challenges are even more pronounced by the lack of experimental testing facilities that replicate the extreme operating environment involving simultaneous high heat and particle fluxes, large time varying stresses, corrosive chemical environments, and large fluxes of 14-MeV peaked fusion neutrons. Fortunately, recent innovations in computational modeling techniques, increasingly powerful high performance and massively parallel computing platforms, and improved analytical experimental characterization tools provide the means to develop self-consistent, experimentally validated models of materials performance and degradation in the fusion energy environment. This presentation will describe the challenges associated with modeling the performance of plasma facing component and structural materials in a fusion materials environment, the opportunities to utilize high performance computing and two examples of recent progress to investigate the dramatic surface evolution of tungsten exposed to low-energy He and H plasmas, with a focus on the nucleation of sub-surface gas bubbles, and the He-defect interactions present further below the surface as a result of higher energy He ion bombardment.

Presentation (PDF File)

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