Radiation asymmetries during disruptions on DIII-D caused by massive gas injectiona)
Abstract
One of the major challenges that the ITER tokamak will have to face during its operations are disruptions. During the last few years, it has been proven that the global consequences of a disruption can be mitigated by the injection of large quantities of impurities. But one aspect that has been difficult to study was the possibility of local effects inside the torus during such injection that could damage a portion of the device despite the global heat losses and generated currents remaining below design parameter. 3D MHD simulations show that there is a potential for large toroidal asymmetries of the radiated power during impurity injection due to the interaction between the particle injection plume and a large n=1 mode. Another aspect of 3D effects is the potential occurrence of Vertical Displacement Events (VDE), which could induce large poloidal heat load asymmetries. This potential deleterious effect of 3D phenomena has been studied on the DIII-D tokamak thanks to the implementation of a multi-location massive gas injection (MGI) system as well as new diagnostic capabilities. This study showed the existence of a correlation between the location of the n=1 mode and the local heat load on the plasma facing components butmore »
- Authors:
-
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- Univ. of California San Diego, San Diego, CA (United States)
- General Atomics, San Diego, CA (United States)
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Publication Date:
- Research Org.:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); General Atomics, San Diego, CA (United States)
- Sponsoring Org.:
- USDOE National Nuclear Security Administration (NNSA); USDOE Office of Nuclear Energy (NE)
- OSTI Identifier:
- 1542704
- Alternate Identifier(s):
- OSTI ID: 1223598; OSTI ID: 1345230
- Report Number(s):
- LLNL-JRNL-752015
Journal ID: ISSN 1070-664X; PHPAEN; 895371
- Grant/Contract Number:
- AC52-07NA27344; AC05-00OR22725; FC02-04ER54698; FG02-07ER54917
- Resource Type:
- Journal Article: Accepted Manuscript
- Journal Name:
- Physics of Plasmas
- Additional Journal Information:
- Journal Volume: 21; Journal Issue: 10; Journal ID: ISSN 1070-664X
- Publisher:
- American Institute of Physics (AIP)
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS
Citation Formats
Commaux, N., Baylor, L. R., Jernigan, T. C., Hollmann, E. M., Humphreys, D. A., Wesley, J. C., Izzo, V. A., Eidietis, N. W., Lasnier, C. J., Moyer, R. A., Parks, P. B., Foust, C. R., Combs, S., and Meitner, S. J. Radiation asymmetries during disruptions on DIII-D caused by massive gas injectiona). United States: N. p., 2014.
Web. doi:10.1063/1.4896721.
Commaux, N., Baylor, L. R., Jernigan, T. C., Hollmann, E. M., Humphreys, D. A., Wesley, J. C., Izzo, V. A., Eidietis, N. W., Lasnier, C. J., Moyer, R. A., Parks, P. B., Foust, C. R., Combs, S., & Meitner, S. J. Radiation asymmetries during disruptions on DIII-D caused by massive gas injectiona). United States. https://doi.org/10.1063/1.4896721
Commaux, N., Baylor, L. R., Jernigan, T. C., Hollmann, E. M., Humphreys, D. A., Wesley, J. C., Izzo, V. A., Eidietis, N. W., Lasnier, C. J., Moyer, R. A., Parks, P. B., Foust, C. R., Combs, S., and Meitner, S. J. 2014.
"Radiation asymmetries during disruptions on DIII-D caused by massive gas injectiona)". United States. https://doi.org/10.1063/1.4896721. https://www.osti.gov/servlets/purl/1542704.
@article{osti_1542704,
title = {Radiation asymmetries during disruptions on DIII-D caused by massive gas injectiona)},
author = {Commaux, N. and Baylor, L. R. and Jernigan, T. C. and Hollmann, E. M. and Humphreys, D. A. and Wesley, J. C. and Izzo, V. A. and Eidietis, N. W. and Lasnier, C. J. and Moyer, R. A. and Parks, P. B. and Foust, C. R. and Combs, S. and Meitner, S. J.},
abstractNote = {One of the major challenges that the ITER tokamak will have to face during its operations are disruptions. During the last few years, it has been proven that the global consequences of a disruption can be mitigated by the injection of large quantities of impurities. But one aspect that has been difficult to study was the possibility of local effects inside the torus during such injection that could damage a portion of the device despite the global heat losses and generated currents remaining below design parameter. 3D MHD simulations show that there is a potential for large toroidal asymmetries of the radiated power during impurity injection due to the interaction between the particle injection plume and a large n=1 mode. Another aspect of 3D effects is the potential occurrence of Vertical Displacement Events (VDE), which could induce large poloidal heat load asymmetries. This potential deleterious effect of 3D phenomena has been studied on the DIII-D tokamak thanks to the implementation of a multi-location massive gas injection (MGI) system as well as new diagnostic capabilities. This study showed the existence of a correlation between the location of the n=1 mode and the local heat load on the plasma facing components but shows also that this effect is much smaller than anticipated (peaking factor of ~1.1 vs 3-4 according to the simulations). There seems to be no observable heat load on the first wall of DIII-D at the location of the impurity injection port as well as no significant radiation asymmetries whether one or 2 valves are fired. This study enabled the first attempt of mitigation of a VDE using impurity injection at different poloidal locations. The results showed a more favorable heat deposition when the VDE is mitigated early (right at the onset) by impurity injection. As a result, no significant improvement of the heat load mitigation efficiency has been observed for late particle injection whether the injection is done “in the way” of the VDE (upward VDE mitigated by injection from the upper part of the vessel vs the lower part) or not.},
doi = {10.1063/1.4896721},
url = {https://www.osti.gov/biblio/1542704},
journal = {Physics of Plasmas},
issn = {1070-664X},
number = 10,
volume = 21,
place = {United States},
year = {Fri Oct 17 00:00:00 EDT 2014},
month = {Fri Oct 17 00:00:00 EDT 2014}
}
Web of Science
Figures / Tables:
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Works referencing / citing this record:
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