From: Lawrence E. Dudek
Sent: Thursday, March 25, 2010 1:30 PM
To: NSTX Center Stack Upgrade Team
Subject: NSTX CSU Project Meeting Notes from 3/24/10
Notes from 3/24 Meeting:

Exisiting condition of PF5 supports and OTF/VV Leg Clearance [Mangra (see VGs) ]
Danny presented some data on the PF 5 supports which shows that the existing shape and alignment forces are relatively smaller than expected.  It's possible the coils have relaxed with time.  Have the coils changed shape in the vertical direction due to the field forces?  (L. Dudek to ask Raftopoulos to arrange for a measurement.) Menard indicated that the alignment in the translation from the center of the machine is most critical measurement (vs the shape).  

Photos of the OTF legs to VV Support Legs were shown with the installed rubber bumpers.  A similar arrangement will be used for the upgrade.

Project Plan [Strykowsky (see VGs)]
Presented the latest scenarios being shown to DOE including the high and low cost ranges.

Dynamic Analysis  [Titus (see VGs)]
Presented analysis showing the TF outer leg modes and frequencies, PF4&5 modes and frequencies.  The DLF for the PF 4 & 5 coils is 1.  Analysis of the latest version of the centerstack to pedestal support was also shown.  The new design used a cylindrical shell instead of four legs in the earlier design.  The analysis indicated an improvement in the stress levels, but the analysis needs some further refinement.  

TF Bundle stresses at Torque Spline [Ali(see VGs)]
Ali presented the latest analysis showing the stresses in the TF bundle caused by the torque from the splined connection to the lid.  Stresses in the insulation were high in some localized regions which is similar to what has been seen in other devices with similar construction (CMOD).

Analysis on the TF Outer Leg [Zhang(see VGs)]
The latest analysis of the OTF legs with a compliant link for OOP forces indicates the stresses in epoxy are around 20MPa which is slightly above the criteria limit of 16MPa.  Further refinement of the model to more accurately reflect the actual design should reduce the stresses.


Viewgraphs will be posted by B. Simmons at:

http://nstx-upgrade.pppl.gov/Project_Meetings/CenterStackUpgrade/index_Meetings.htm

Outstanding Action Items (last update 3/24/2010)
Action: Structural design criteria has a table with likelihood of failures that is in the NSTX (orig.) GRD.  Structural design criteria needs work to be released such as references 
STATUS: Draft back with Irv Zatz and P. Titus for revision. (Status 3/17)

Action: The idea of a Design Load Requirements (Criteria) Document is a good one. Action: Mark Smith to pull this together for the Structures– Need this BEFORE the PDR

Action:  We have a set of Calculations signed off, but not all were checked for the CDR.  These calcs need to be updated and checked (by PDR?). ACTION: Titus

Action: Neumeyer to comment on VDE plasma disruption used to analyze the stresses in the PP brackets and fasteners.  Is it a realistic scenario disruption?  STATUS: 3/17-Poloidal straps were removed from model, stresses still high need to fine tune input fields to determine if the stresses are realistic.

________________

Larry