Supported by NSTX PFC Upgrade Plans College W&M R. Kaita for the NSTX Team Colorado Sch Mines Culham Sci Ctr Columbia U U St. Andrews CompX Princeton Plasma Physics Laboratory York U General Atomics Chubu U INEL Fukui U Plasma Facing Components Meeting Johns Hopkins U Hiroshima U LANL Hyogo U LLNL UCLA Kyoto U Lodestar Kyushu U MIT August 6, 2010 Kyushu Tokai U Nova Photonics NIFS New York U Old Dominion U Niigata U ORNL U Tokyo PPPL JAEA PSI Hebrew U Princeton U Ioffe Inst Purdue U RRC Kurchatov Inst SNL TRINITI Think Tank, Inc. KBSI UC Davis KAIST UC Irvine POSTECH UCLA ASIPP UCSD ENEA, Frascati U Colorado CEA, Cadarache U Illinois IPP, Jülich U Maryland IPP, Garching U Rochester ASCR, Czech Rep U Washington U Quebec U Wisconsin
Outline • General comments on Liquid Lithium Divertor (LLD) technical performance • Effects of high power density on LLD • Test facilities at PPPL • Design of improved lithium loading for LLD • Inner divertor upgrade with molybdenum tiles - 2 -
NSTX operation with Liquid Lithium Divertor demonstrates basic soundness of design* Side view of LLD and divertor tiles Pivoting corner supports • No excessive heating or deleterious introduction of impurities from LLD during high-power NSTX plasma operations > Validates design with thin, molybdenum-sprayed stainless steel liner on copper backing • No unanticipated LLD displacement due to thermal effects, eddy currents, or other potential sources of mechanical stress > Edge mounting scheme functioning as designed *See paper SP3C-32 by R. Ellis et al. in 36 th International Conference on Plasma Science and 23 rd Symposium on Fusion Engineering R. Ellis - 3 -
Discoloration only observation on LLD after high power neutral beam injection plasmas Location of Limits of LLD outer strike point “Diagnostic” tile • No apparent damage to LLD or “diagnostic” tiles separating LLD quadrants observed with up to 4 MW of neutral beam injection F. Scotti - 4 -
Results consistent with offline studies of thermal response of LLD sample • Test chamber on diagnostic neutral beamline – MSE-LIF neutral beam heat flux ~ 10 MW/m 2 comparable to NSTX divertor – Thermocouples and IR camera measure surface and bulk - 5 - temperatures
Offline facilities also available with lithium evaporation capability for NSTX PFC testing • C128 chamber (pictured) has heated proto-LLD sample for Camera View controlled testing – LITER 1C for deposition RGA – differentially pumped RGA LLD sample arm LITER port QDM – camera for surface Glow feedthru reflectivity measurements – QDM for LITER deposition and plate evaporation – various species glows possible (characterized by Langmuir probe) Gas inlet – Lithium Conductivity Diagnostic for surface quality and thickness measurements (possible installation in NSTX PMI probe) - 6 -
More efficient LLD loading planned with liquid lithium fill system • Proposed concept adopts LITER Liquid Lithium Fill system (LIFTER) technology being used to refill LITERS • Concept • 1 station per plate (one per 90°) • 3 components per fill station: 1. External LIFTER-like unit 2. Vertical pipe from port to toroidal distribution pipe near outer wall 3. Moly or ATJ clad 316-SS pipe (spoke) from distribution pipe to plate 2 3 2 1 J. Timberlake - 7 -
Concept for molybdenum plasma-facing surface for NSTX inboard divertor under analysis Horizontal Inboard Divertor Vertical Inboard LLD-1 Divertor H. Kugel Tee-Bar, screw & Belleville washer - 8 -
NSTX Team Contributors and Acknowledgements* H. Kugel 1), T. Abrams 1), M. G. Bell 1), R. Bell 1), R. Ellis 1), S. Gerhardt 1), T. Gray 2), M. Jaworski 1), J. Kallman 1), A. L. Roquemore 1), H. Schneider 1), F. Scotti 1), C. H. Skinner 1), V. Soukhanovskii 3), V. Surla 4), and J. Timberlake 1) 1) Princeton Plasma Physics Laboratory, Princeton, NJ 2) Oak Ridge National Laboratory, Oak Ridge, TN 3) Lawrence Livermore National Laboratory, Livermore, CA 4) University of Illinois at Urbana-Champaign, Champaign, IL *Work supported in part by US DOE Contracts DE-AC02-09CH11466, DE-AC04-94AL85000, DE-AC52-07NA27344, and DE-AC05-00OR22725 - 9 -
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