The Application of Mass Spectrometry Techniques for the Benefit of Tungsten Impurity Transport Research and Nuclear Fusion

Several barriers prevent the capability of on the grid nuclear fusion power plants. With the research presented here, these issues are confronted and the work makes progress towards addressing known gaps in the fusion community’s understanding of material and impurity migration in fusion devices. Recent successes that were achieved during the DIII-D metal rings campaign of the summer in 2016 must continue to develop in preparation for testing on additional plasma devices. During this campaign, impurities generated from the metal tiles of DIII-D were collected on graphite collector probes. These were then studied with several techniques, and it has been shown that traditional analytical techniques such as Rutherford backscattering and inductively coupled plasma mass spectrometry (ICP-MS) are able to determine the presence and isotopic ratios of heavy metals. Adding to these tools, an in depth study of laser ablation mass spectrometry (LAMS) is necessary. Methods have been developed so that they may be used in direct solid sample analysis of graphite collector probes using LAMS. With these procedures in place, a comparative study has be completed between the LAMS system and traditional aqueous intake ICP-MS. With these results in hand, empirical evidence may be used to benchmark computational techniques for interpretive modeling of impurity transport in fusion devices like the DIVIMP-OEDGE-WallDYN code.