NSTX Team Meeting

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NSTX Team Meeting
Columbia U Comp-X GA INEL JHU LANL LLNL Lodestar M
IT Nova Photonics NYU ORNL PPPL PSI SNL UC
Davis UC Irvine UCLA UCSD U Maryland U New
Mexico U Wash U Wisc UKAEA Fusion Hiroshima
U HIST Kyushu Tokai U Niigata U Tsukuba U U
Tokyo Ioffe Inst TRINITI KBSI KAIST ENEA Frascati
March 13, 2003
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Meeting Agenda

• Updates C. Neumeyer - design effort, A. Von
  Halle - outage activities and plan, M. Bell -
  Research Op.
• OFES Visit on March 14, 2003. (Presentations by
  M. Williams, R. Hawryluk for J. Schmidt, M. Ono)
• FWP Meeting on March 18 - 19, 2003
  (Presentations by M. Peng and M. Ono)

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While the TF fault was an unfortunate event, we
were fortunate in many ways.

• The damage was limited to the inner TF joint
  area. No other significant collateral damages.
  (OH, PFs, CHI, diagnostics, vacuum system, etc.)
• In fact, the high vacuum remained intact. TF
  bundle was lifted out of the machine without
  breaking vacuum.
• The undisturbed vacuum condition enabled the
  important post operation diagnostic calibrations
• TVTS, CHERS, Edge rotation spectroscopy
  (completed)
• Pressure gauge, gas injection system (completed)
• FIR camera (the high temperature bakeout needed
  for the calibration to be performed next week)

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Lesson learned and moving on

• A joint design weakness was uncovered by this
  incident and through detailed analyses.
• Improved joint with sufficient margin being
  designed. Significant longer term benefit
• - Improve operational reliability
• - Achieve routine operations up to full
  parameters
• - Reduce future maintenance and repair liability
• The TF bundle replacement can be funded within
  the present operating budget and the
  manufacturing is relatively quick once the joint
  design is approved.

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Cash Generated From Not Running

• Saving not including the base staff salary
• Reduced Energy Budget 236 k
• LN2 SF6 Savings 44 k
• Reduction in overtime 52 k
• __________________________________________________
  ______________________
• Total Cash Available 332 k

The NSTX engineering and technical staff will
be working on the TF bundle, post operational,
and FY 03 outage related activities. Some
targeted areas of collaborations being discussed
(e.g. high power radio frequency engineering)
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New TF Bundle Preliminary Fabrication Cost

• New TF Bundle will have improved cooling water
  and joint design
• Procurements (MS) 132 k
• Bundle manufacturing shop labor 100 k
• Joint Improvement items 120 k of bolts,
  flags, etc.
• __________________________________________________
  ______________________
• Total 350k

The estimated cost for MS, shops, improvements,
etc. is 350 k which roughly balances the
cash generated from not running.
We can build the TF bundle within this years
budget.
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NSTX Schedule
Original Plan
FY 03
FY 04
21 Run Weeks
Outage
12 Run Weeks
Outage
Revised Plan
FY 03
FY 04
21 Run Weeks
Outage
Outage
4 Run Weeks
Shake down
TF Bundle Fab
The outage is accelerated by three months. TF
bundle related activities will receive highest
priority. New plan allows FY 04 extended outage.
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FY 03 Run Yielded Important Results
Confirmed the improved HHFW antenna power
performance from 3.5 MW in FY 02 to 5 MW in FY 03
HHFW antenna. Confirmed the improved
resistance to arc on the new CHI absorber. The
new 51 channel CHERS system successfully
commissioned. The edge poloidal and toroidal
spectroscopy successfully commissioned. The
real-time plasma control with the real time EFIT
code implemented. Reduced locked-modes and
toroidal beta higher by 15 - reduced error
field? 1 MA high beta poloidal discharge with
low loop voltage ( 0.2 V) obtained. Lower
Single Null discharges reached ?N 7 and ?P
2.5 during the current ramp down, with the plasma
going slightly diamagnetic. Tested gas
injectors at different poloidal locations showing
easier H-mode access for the inboard (high field
side mid-plane and shoulder) gas injectors.
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Researchers are productively engaged as well
Perform post operation diagnostic calibrations,
data analyses, and write papers!
Present results at meetings (ITPA, APS, TTF -
April, RF Conference- May, EPS - July,
International ST workshop - Sept, and others)
Prepare for the 5 Year Facility Review planned in
June. Support in the outage activities in
preparation for the FY 04 run. Pursue mutually
beneficial collaboration opportunities using NSTX
strength - DIII-D (RWM, Fast Ion MHD,
Confinement, Pedestal Physics) - C-Mod (X-ray
spectroscopy, Edge Turbulences,
Micro-instability, RF Operations, MSE) - MAST
(EBW, Boundary Physics, Confinement Scaling) -
Support ITER costing
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The TF Fault Was a Problem We Can Learn From and
Fix
Fortunately, the damage was limited to the
lower TF joint area. Detailed analyses
revealed weakness in the original joint design
and an improved robust design is being developed.
The cost of TF bundle fabrication can be
funded from the cash saved from the electricity,
other consumables, and overtime from the
operations. This incident will improve our
understanding of the TF joint technology and help
improve facility reliability and availability for
years to come. We are enhancing the
inter-facility collaborations (DIII-D, C-Mod,
MAST). NSTX team is focused on completing the
remaining FY 03 tasks and prepare for the FY 04
operations with the newly improved TF bundle to
support an exciting research plan.
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Supplemental VG
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TF Background
NSTX first plasma achieved in Feb. 1999.
Dec. 15, 2000, water leak was found on the TF
bundle. Leaks fixed by epoxy except TF 6A.
Leaks are traced to original manufacturing
problem.
2001 Operations conducted with TF 6A
uncooled. 2001 Procured copper bars for a new
TF.
2002 Flourinert cooling system implemented.
July 2002, 6 kG operations conducted for 2
weeks. Summer of 2002, TF joints were
examined. Lower joints were quite loose and were
reworked. All joints were brought to
specification. Jan. 8, the NSTX plasma
operations started. TF limited to 4.5 kG.
Feb. 3-7, 2003, the upper joints re-torqued to
specification. Feb. 14, the TF fault occurred
with the lower joint 8A failing. The lower
joints were scheduled to be re-torqued during
Feb. 24 - 28. Feb. 24, the TF bundle was
removed without breaking high vacuum.
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Original TF Bundle Fabrication Cost

• Old TF bundle costed about 344 k to fabricate
  in FY 97-98
• Copper ( 22 k)
• Machining ( 203 k)
• Insulation/material ( 12 k)
• Bundle manufacturing ( 107k)
• The copper of the old TF bundle is kept as the
  future spare. (3 conductors damaged out of 36
  total)