Speaker
Dr
Stefan Gerhardt
(Princeton Plasma Physics Laboratory)
Description
The NSTX-U device began operation in 2016, producing 10 weeks of commissioning and scientific operations. However, a number of technical issues, including the failure of a key diverter coil, resulted in the suspension of operations. A comprehensive extent of condition review was initiated at the request of the Department of Energy; this paper will summarize the result of that process, focusing on the design and implementation improvements that are in progress in order to resume operation and increase reliability. Many elements of the physics design have been revisited as part of the Recovery, although most key NSTX-U mission goals remain. New requirements for the divetor heat fluxes have been defined, based on recent SOL heat flux width models. New halo currents loads have been determined based on combining data from NSTX, NSTX-U, MAST, and conventional aspect ratio devices. New error field analysis has been conducted, with the goal of optimizing both the global MHD stability and minimizing PFC heat flux asymmetries for scenarios with large poloidal flux expansion. New divertor coil current requirements have been defined, based on the tolerable heat fluxes and current drive for the various potential equilibria. Numerous design improvements are being included as part of the Recovery effort, with a primary goal of supporting flexible operations at BT=1 T, IP=2 MA, Pinj=10 MW, and tpulse=5 seconds. New designs of graphite plasma facing components utilize castellations to reduce the mechanical stresses, allowing tiles to reach surface temperature limits, ~1600 degC, driven by sublimation. Improved divertor coil designs simplify fabrication and facilitate turn-to-turn testing. Modifications to the NSTX-U vacuum chamber will eliminate one the ceramic insulators necessary for coaxial helicity injection (CHI), increasing system reliability at the expense of the CHI research capability. The physics and engineering R&D activities that support Recovery will be summarized, along with highlights of the new design. This work was supported by U.S. DOE Contract D-AC02-09CH11466 and DE-AC05-00OR22725
| Country or International Organization | United States of America |
|---|---|
| Paper Number | FIP/P3-63 |
Primary author
Dr
Stefan Gerhardt
(Princeton Plasma Physics Laboratory)
Co-authors
Mr
Alan Basile
(Princeton Plasma Physics Laboratory)
Mr
Andrei Khodak
(Princeton Plasma Physics Laboratory)
Mr
Andy Gao
(Princeton Plasma Physics Laboratory)
Mrs
Ankita Jariwala
(Princeton Plasma Physics Laboratory)
Mr
Arthur Brooks
(Princeton Plasma Physics Laboratory)
Mr
Atiba Brereton
(Princeton Plasma Physics Laboratory)
Dr
Brent Stratton
(Princeton Plasma Physics Laboratory)
Mr
Brian Linn
(Princeton Plasma Physics Laboratory)
Mrs
Carmella Ciummo
(Princeton Plasma Physics Laboratory)
Mr
Charles Neumeyer
(Princeton Plasma Physics Laboratory)
Mr
Christopher Freeman
(Princeton Plasma Physics Laboratory)
Mr
Dang Cai
(Princeton Plasma Physics Laboratory)
Mr
Doug Downing
(Princeton Plasma Physics Laboratory)
Mr
Doug Loesser
(Princeton Plasma Physics Laboratory)
Dr
Feng Cai
(Princeton Plasma Physics Laboratory)
Dr
Frank Hoffmann
(Princeton Plasma Physics Laboratory)
Mr
Frank Jones
(Princeton Plasma Physics Laboratory)
Mr
Gregory Tchilinguirian
(Princeton Plasma Physics Laboratory)
Mrs
Gretchen Zimmer
(Princeton Plasma Physics Laboratory)
Mrs
Han Zhang
(Princeton Plasma Physics Laboratory)
Mr
Hans Schneider
(Princeton Plasma Physics Laboratory)
Mr
Irving Zatz
(Princeton Plasma Physics Laboratory)
Mrs
Jessica Guttenfelder
(Princeton Plasma Physics Laboratory)
Mr
John Dellas
(Princeton Plasma Physics Laboratory)
Mr
Jonathan Klabacha
(Princeton Plasma Physics Laboratory)
Dr
Jonathan Menard
(Princeton Plasma Physics Laboratory)
Dr
Jong-Kyu Park
(Princeton Plasma Physics Laboratory)
Mr
Joseph Petrella
(Princeton Plasma Physics Laboratory)
Mr
Keith Erickson
(Princeton Plasma Physics Laboratory)
Mr
Lawrence Dudek
(Princeton Plasma Physics Laboratory)
Mr
Manish Kumar
(Princeton Plasma Physics Laboratory)
Mr
Mark Cropper
(Princeton Plasma Physics Laboratory)
Mr
Mark Sibilia
(Princeton Plasma Physics Laboratory)
Mr
Mark Smith
(Princeton Plasma Physics Laboratory)
Dr
Matthew Reinke
(ORNL)
Mr
Michael D'Agostino
(Princeton Plasma Physics Laboratory)
Dr
Michael Jaworski
(Princeton Plasma Physics Laboratory)
Mr
Michael Kalish
(Princeton Plasma Physics Laboratory)
Mr
Michael Mardenfeld
(Princeton Plasma Physics Laboratory)
Mr
Michael Viola
(Princeton Plasma Physics Laboratory)
Mr
Mounir Awad
(Princeton Plasma Physics Laboratory)
Mr
Nathanial Dean
(Princeton Plasma Physics Laboratory)
Nathaniel Ferraro
(Princeton Plasma Physics Laboratory)
Mr
Nevell Greenough
(Princeton Plasma Physics Laboratory)
Mr
Neway Atnafu
(Princeton Plasma Physics Laboratory)
Mrs
Nicole Allen
(Princeton Plasma Physics Laboratory)
Mr
Peter Titus
(Princeton Plasma Physics Laboratory)
Mr
Richard Burke
(Princeton Plasma Physics Laboratory)
Mr
Robert Ellis
(Princeton Plasma Physics Laboratory)
Mr
Russell Feder
(Princeton Plasma Physics Laboratory)
Mr
Steven Raftopoulos
(Princeton Plasma Physics Laboratory)
Mr
Tim Stevenson
(Princeton Plasma Physics Laboratory)
Dr
Travis Gray
(Oak Ridge National Laboratory)
Dr
Weiguo Que
(Princeton Plasma Physics Laboratory)
Mrs
Wenping Wang
(Princeton Plasma Physics Laboratory)
Mr
William Blanchard
(Princeton Plasma Physics Laboratory)
Mr
Yuhu Zhai
(Princeton Plasma Physics Laboratory)
