Fuel recycling and impurity characteristics in long-pulse H-mode plasmas with full metal and dynamically coated walls on EAST

Wang, Z.; Sun, Z.; Wu, K.; Huang, Y.; Xu, W.; Guan, Y. H.; Huang, M.; Zhang, H. M.; Yang, J. J.; Duan, Y. M.; Zhang, L.; Yu, Y. W.; Gong, X. Z.; Zuo, G. Z.; Hu, J. S.

doi:10.1088/1741-4326/adfd71

Title: Fuel recycling and impurity characteristics in long-pulse H-mode plasmas with full metal and dynamically coated walls on EAST

Journal Article · Thu Aug 28 00:00:00 UTC 2025 · Nuclear Fusion

DOI: https://doi.org/10.1088/1741-4326/adfd71 · OSTI ID:2588130

^[1];

^[2]; Wu, K. ^[3];

^[3];

^[4]; Guan, Y. H. ^[1]; Huang, M. ^[3]; Zhang, H. M. ^[3]; Yang, J. J. ^[1]; Duan, Y. M. ^[3]; Zhang, L. ^[3];

^[3]; Gong, X. Z. ^[3];

^[3]; Hu, J. S. ^[3]

Chinese Academy of Sciences, Hefei (China); University of Science and Technology of China, Hefei (China)
Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
Chinese Academy of Sciences, Hefei (China)
Hefei Comprehensive National Science Center (China)

We report the basic behaviors of fuel recycling and impurity accumulation during >100 s long-pulse H-mode plasma under full metal wall conditions on EAST. Significant fuel recycling and impurity rising, particularly from heavy impurities, have been observed when operating with a bare metal wall or a deteriorate real-time coated wall, which severely limits the duration of H-mode discharges. To address this issue, a novel dynamic wall coating technique combining feedforward and feedback controls has been successfully developed. The feedforward control presets the Li powder injection rate based on prior experimental observations, whereas the feedback control dynamically modulates the Li injection rate in response to real-time Li-II line emission measurements. Using this approach, a 605 s H-mode plasma has been achieved with fuel recycling and impurity level maintained stable. This result extends the previous record of a 403 s long-pulse H-mode plasma Gong et al (2024 Nucl. Fusion 64 112013) by over 200 s. It demonstrates the effectiveness of the dynamic powder injection technique in controlling fuel recycling and impurities accumulation, while prolonging plasma duration. These findings offer valuable insights into potential applications of other low-Z powder, such as boron, in ITER.

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Research Organization:: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)

Sponsoring Organization:: USDOE

Grant/Contract Number:: AC02-09CH11466

OSTI ID:: 2588130

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 10 Vol. 65; ISSN 0029-5515; ISSN 1741-4326

Publisher:: IOP PublishingCopyright Statement

Country of Publication:: United States

Language:: English

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