NSTX Supported by NSTX Centerstack Upgrade Project Meeting P. Titus March Insulation Short Beam Tests – Failure Modes Ripple Loads on PF PF4/5 Existing Support Analysis

Top flag Von Mises Top flag hoop stress 315 MPa (45.7 ksi) 257 MPa (37.3 ksi) 73.7 MPa (10.7 ksi) Han Zhang Current Diffusion/Thermal/Stress Model We Expect De-Lamination

Figure 33 - Bonded tape delaminated from copper turn Figure 34 - Sleeve of bonded glass fiber tape where copper turn slid out TFTR D&D PROJECT FINAL EXAMINATION AND TESTING OF THE TFTR TF-COILS December 18, 2002 Irving J. Zatz

Broke at only 100 lbs Broke at Kapton Bonds Withstood 21kV after air gap tracking fixed.

U.S. ITER Large-Scale Compression-Fatigue Tests of CS Coil Insulation 27 June 2008

Stresses Due to OH2 Reverse Current Fault, Alcator C-Mod Belleville Preload is Applied as Nodal Forces on the Top of the model Analysis Predicted De-Bonding but Not Failure Inspection Showed Crazing Here No Operational Problems have been Experienced

Conclusion: Some De-Lamination is Expected Parting Planes must be predictable and not Cause Tearing of Fiberglass Insulator OH Kapton Interleaved Insulation Will Part Reliably – Like Old ITER Design Recent Measured Results for the CTD 425 System Show Preferential Failures at Copper Bond Surface, But Sufficient Shear Strength to Support TF Torsional Loads

With Plasma No Plasma Without Existing Support Strut

With Existing Support Strut 180 Mpa or 26ksi is Marginal for Static Weld Allowable Present 96 Scenarios produce ~22 ksi (next Slide) Won’t Pass Fatigue.

Results from Influence Coefficient Multiplication for Sx in RSYS 5 (cylindrical). With No Column This Stress Can be Considered from PF5 Loads Only +13kA/- 24 kA Scenario from Latest ( as of March 2011) Design Point Spreadsheet

Present Column Doesn’t Do Much and Doesn’t Compare Well with the Added 3.5 inch Column Could we Replace it?

TF Ripple Loads – Figure Created by Subtracting the PF+TF Load File from the PF Only File, Then Plotting Only PF Loads

TF Ripple Loads on PF 4 and 5 Upper Plotted with TF leg Segments to Show Torque Loading Near the TF Legs TF Ripple Loads on PF Coils are Included in Willard’s, Han’s, Andrei’s and Titus’ Loads – But not Influence Coefficient Calculations.