One of the most elusive challenges when talking about fusion reactors, is the selection of an appropriate material for plasma-facing components. Significant resources and experimental programs have been dedicated to the study of tungsten and carbon; these are the frontline choices for such an application. The goal of this study was to determine if graphene, a 2D allotrope of graphite, can be used as a coating for tungsten surfaces exposed to plasma conditions expected during the first phase of operation in the ITER campaign. Growth, transfer, and characterization of the graphene films were performed in-house as demonstrated by the figure on the right.
Exposure to deuterium and helium plasmas was performed in the PISCES-A facility in San Diego, CA. Results of the study show that the graphene shows some resilience towards both types of exposure, with high helium fluences having a stronger effect on the amorphization of the graphene film. Another major takeaway was the reduction in the thickness of surface morphology features found on tungsten when it is exposed to a plasma. Application of the membrane reduced the tungsten fuzz thickness by ~40%. These results show that a hybrid approach of tungsten and smart materials could be a potential avenue for PFC’s in next-generation reactors.
These results were published recently in the Journal of Nuclear Materials (https://authors.elsevier.com/a/1c%7EjH54hEIA8g).
*Funding for this work was provided by the Department of Energy and the Grainger Foundation. The work of M. Navarro was supported by the U.S. Department of Energy [DE-SC0013911] and the Grainger Foundation. The growth of graphene and development of transfer protocols (M. Zamiri and M. Lagally) were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences (DOE) Award [DE-FG02 03ER46028]. The work of R. Doerner was supported by the U.S. Department of Energy [DE-FG02-07ER54912]. We acknowledge the use of facilities and instrumentation supported by NSF through the University of Wisconsin Materials Research Science and Engineering Center[DMR-1121288]..