U.S. Department of EnergyOffice of Scientific and Technical Information
Development and experimental qualification of novel disruption prevention techniques on DIII-D
Abstract
Novel disruption prevention solutions spanning a range of control regimes are being developed and tested on DIII-D to enable ITER success. First, a new real-time control algorithm has been developed and tested for regulating nearness to stability limits and maintaining safety-margins. Its first application has been for reliable prevention of vertical displacement events (VDEs) by adjusting plasma elongation (κ) and the inner-gap between the plasma and inner-wall in response to real- time open-loop VDE growth rate (γ) estimators. VDEs were robustly prevented up to average open-loop growth rates of 800 rad/s with initial tunings, with only applying shape modification when near safety limits. Second, the disruption risk during fast, emergency shutdown after large tearing and locked modes can be significantly improved by transitioning to a limited topology during shutdown. More than 50% of emergency limited shutdowns after locked modes reach a final normalized current I N < 0.3 before terminating, scaling to the 3 MA ITER requirement. This is in contrast to diverted shutdowns, the majority of which disrupt at I N > 0.8. Despite improvements, these results highlight the critical importance of early prevention. Third, a novel emergency shut down method has been developed which excites instabilities to formmore »
- Authors:
-
- OSTI
- Publication Date:
- DOE Contract Number:
- FC02-04ER54698; SC0014264; AC02-09CH11466; AC52-07NA27344
- Research Org.:
- General Atomics, San Diego, CA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Plasma Science and Fusion Center; Princeton Plasma Physics Lab. (PPPL), Princeton, NJ (United States); Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Org.:
- USDOE Office of Science (SC), Fusion Energy Sciences (FES); USDOE National Nuclear Security Administration (NNSA)
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY
- OSTI Identifier:
- 1888174
- DOI:
- https://doi.org/10.7910/DVN/WKUUGH
Citation Formats
Barr, Jayson, Sammuli, Brian, Humphreys, Dave, Olofsson, K. Erik J., Du, Xiaodi, Rea, Cristina, Wehner, Will, Boyer, Mark, Eidietis, Nicholas, Granetz, Robert, Hyatt, A., Liu, Tong, Logan, Nikolas, Munaretto, Stefano, Strait, E., and Wang, Zhirui. Development and experimental qualification of novel disruption prevention techniques on DIII-D. United States: N. p., 2022.
Web. doi:10.7910/DVN/WKUUGH.
Barr, Jayson, Sammuli, Brian, Humphreys, Dave, Olofsson, K. Erik J., Du, Xiaodi, Rea, Cristina, Wehner, Will, Boyer, Mark, Eidietis, Nicholas, Granetz, Robert, Hyatt, A., Liu, Tong, Logan, Nikolas, Munaretto, Stefano, Strait, E., & Wang, Zhirui. Development and experimental qualification of novel disruption prevention techniques on DIII-D. United States. doi:https://doi.org/10.7910/DVN/WKUUGH
Barr, Jayson, Sammuli, Brian, Humphreys, Dave, Olofsson, K. Erik J., Du, Xiaodi, Rea, Cristina, Wehner, Will, Boyer, Mark, Eidietis, Nicholas, Granetz, Robert, Hyatt, A., Liu, Tong, Logan, Nikolas, Munaretto, Stefano, Strait, E., and Wang, Zhirui. 2022.
"Development and experimental qualification of novel disruption prevention techniques on DIII-D". United States. doi:https://doi.org/10.7910/DVN/WKUUGH. https://www.osti.gov/servlets/purl/1888174. Pub date:Thu Jun 09 00:00:00 EDT 2022
@article{osti_1888174,
title = {Development and experimental qualification of novel disruption prevention techniques on DIII-D},
author = {Barr, Jayson and Sammuli, Brian and Humphreys, Dave and Olofsson, K. Erik J. and Du, Xiaodi and Rea, Cristina and Wehner, Will and Boyer, Mark and Eidietis, Nicholas and Granetz, Robert and Hyatt, A. and Liu, Tong and Logan, Nikolas and Munaretto, Stefano and Strait, E. and Wang, Zhirui},
abstractNote = {Novel disruption prevention solutions spanning a range of control regimes are being developed and tested on DIII-D to enable ITER success. First, a new real-time control algorithm has been developed and tested for regulating nearness to stability limits and maintaining safety-margins. Its first application has been for reliable prevention of vertical displacement events (VDEs) by adjusting plasma elongation (κ) and the inner-gap between the plasma and inner-wall in response to real- time open-loop VDE growth rate (γ) estimators. VDEs were robustly prevented up to average open-loop growth rates of 800 rad/s with initial tunings, with only applying shape modification when near safety limits. Second, the disruption risk during fast, emergency shutdown after large tearing and locked modes can be significantly improved by transitioning to a limited topology during shutdown. More than 50% of emergency limited shutdowns after locked modes reach a final normalized current I N < 0.3 before terminating, scaling to the 3 MA ITER requirement. This is in contrast to diverted shutdowns, the majority of which disrupt at I N > 0.8. Despite improvements, these results highlight the critical importance of early prevention. Third, a novel emergency shut down method has been developed which excites instabilities to form a warm, helical core post-thermal quench. The current quench extends to ~100ms and avoids VDEs and runaway electron generation. Novel real-time machine learning disruption prediction has been integrated with the DIII-D proximity controller, and a real- time compatible multi-mode MHD spectroscopy technique has been developed. Results presented here were enabled by a focused effort, the Disruption Free Protocol, in DIII-D’s 2019-20 campaign to complement disruption prevention experiments with a large piggy-back program. In addition to testing novel techniques, it is estimated to have helped avoid 32 potential disruptions in piggyback operations with rapid, early shutdowns after large rotating n=1 or locked modes.},
doi = {10.7910/DVN/WKUUGH},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Jun 09 00:00:00 EDT 2022},
month = {Thu Jun 09 00:00:00 EDT 2022}
}