NSTX Overview

							                    Supported by


                                       Columbia U
                                           Comp-X
                                                 GA
                                               INEL
                                                JHU
                                              LANL
                                              LLNL

NSTX Team Meeting                        Lodestar

                                   Nova Photonics
                                                 MIT

                                                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
   March 13, 2003                  Kyushu Tokai U
                                         Niigata U
                                        Tsukuba U
                                           U Tokyo
                                          Ioffe Inst
                                            TRINITI
                                              KBSI
                                             KAIST
                                    ENEA Frascati
                 Meeting Agenda

o Updates: C. Neumeyer - design effort, A. Von Halle -
outage activities and plan, M. Bell - Research Op.

o OFES Visit on March 14, 2003. (Presentations by M.
Williams, R. Hawryluk for J. Schmidt, M. Ono)

o FWP Meeting on March 18 - 19, 2003 (Presentations
by M. Peng and M. Ono)
While the TF fault was an unfortunate event,
     we were fortunate in many ways.

o The damage was limited to the inner TF joint area. No
other significant collateral damages. (OH, PFs, CHI,
diagnostics, vacuum system, etc.)

o In fact, the high vacuum remained intact. TF bundle
was lifted out of the machine without breaking vacuum.

o 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)
Lesson learned and moving on
o A joint design weakness was uncovered by this
incident and through detailed analyses.
o 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

o The TF bundle replacement can be funded
within the present operating budget and the
manufacturing is relatively quick once the joint
design is approved.
           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)
  New TF Bundle Preliminary Fabrication Cost

• New TF Bundle will have improved cooling water and joint
design:
   - Procurements (M&S)                     $ 132 k
   - Bundle manufacturing shop labor $ 100 k
   - Joint Improvement items                ~ $ 120 k of bolts, flags, etc.
   ________________________________________________________________________

       Total                                ~ $ 350k

 The estimated cost for M&S, shops, improvements, etc. is
 ~ $ 350 k which roughly balances the cash generated from
 not running.

We can build the TF bundle within this year’s budget.
                      NSTX Schedule
Original Plan
                FY 03                              FY 04
              12 Run Weeks        Outage        21 Run Weeks     Outage



Revised Plan
                 FY 03                             FY 04
                         Outage            21 Run Weeks        Outage
4 Run Weeks

                    TF Bundle Fab    Shake
                                     down
   • The outage is accelerated by three months.
   • TF bundle related activities will receive highest priority.
   • New plan allows FY 04 extended outage.
      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.
   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
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.
Supplemental VG
                        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.
       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)