1. FDR - NCSX Central Solenoid Support Structure Fred Dahlgren Joe Rushinski 6 Sept 2006

2. FDR - Central Solenoid Support Structure - 9/6/06 Charge: Does the coil structure provide adequate support for the PF1a coils with sufficient margins of safety? Have the interfaces with other sub-systems been defined and are they compatible? Are the drawings and supporting documents complete and ready for sign-off? Has the analysis been documented and checked? Are the cost, procurement and assembly schedule consistent with the program schedule and budget?

3. Design Description: The structure consists of solution annealed 304L stainless weldments fabricated mainly from 1/4”, 3/8”, 1/2” and 3/4” thick plate (µ < 1.02). The individual structural segments are 120 degrees with G-11CR insulating plates, bushings, and washers between the adjacent segments. A mid-plane sub-assembly will space the top & bottom PF1A coils (re- claimed from NSTX), at ± 40 cm from the mid-plane. The top and bottom sub-assemblies will have six 3/4” tie rods with nuts and belleville washers and will provide a 12,000 lb. axial pre-load clamping force on the two PF1A coils. The bellevilles’ will accommodate up to 0.015” of differential thermal contraction/expansion (~ 0.007” amount required). Twelve radial support arms (6-top & 6-bottom) will attach the solenoid structure to the main coil structure. All bolting materials (nuts, bolts, washers, etc.) will be 316 stainless. FDR - Central Solenoid Support Structure - 9/6/06

4. PF1a Coil Modification: Water fittings & tubes must be re-worked & re- insulated Coil Description: 48 turn double layer spiral wound, 0.787” square CDA107 drawn Cu conductor with 0.354 dia. coolant hole. Insulation: 0.026” thk. CTD112P w/0.0065” Kapton-1/2-lapped (0.052” turn to turn) & 0.054” thk. ground wrap. Coil Dimensions: 12.8” I.D. 16.26” O.D. 21.08” axial length 48 turns Cu area: 0.52 sq.in. Hole dia.: 0.354” Leads: 12.6” & 16.9” Fabr. Details see: NSTX-SPEC-13-041

5. FDR - Central Solenoid Support Structure - 9/6/06 PF1a Coil/Structure Assembly - Pre-assembled

6. FDR - Central Solenoid Support Structure - 9/6/06 111.5”

7. FDR - Central Solenoid Support Structure - 9/6/06 Assembly will have ~55” clearance for lift

8. Materials: 304L solution annealed plates ER316LN weld filler 316L nuts, bolts, washers, & rods G10/11CR insulating plates @ 120 deg. G10/11CR washers & bushings Copper tubing Brass Swagelok (B-600 series) tube fittings Interfaces: Cryogen cooling lines connect to top & bottom LN2 feed/return lines. Pressure & flow requirements defined, connecting lines (with insulating breaks) to cryogen supply & return plenums are needed. Four thermocouples are required to monitor coil inlet/outlet. Bus pads at the top & bottom locations are defined. Bus connection to power supply are needed. Bus interface defined, scenario A.1.3.4 defines the current & voltage requirements. Top & bottom mounting pads bolt to same threaded holes to be used for permanent solenoid supports. Loading @ support interface defined.

9. FDR - Central Solenoid Support Structure - 9/6/06 * * From Allegheny Ludlum Technical Data Blue Sheet

10. 2/3rd Yield allowable @80K = 46.6ksi 304L Properties* * From Allegheny Ludlum Technical Data Blue Sheet

11. FDR - Central Solenoid Support Structure - 9/6/06 Cooling analysis: Cooling Analysis Shows < 1 deg.K rise per pulse & no ratcheting Plot of the PF1a exit temperature vs. time DP = 10 psi Qdot = 1.14 GPM AMPS = 19.3 kA ESW = 0.16 sec. Rep.Rate = 900 sec. 0.787 Ø 0.354

12. FDR - Central Solenoid Support Structure - 9/6/06 FEA Model of PF1A & Supporting Structure: A 1/6th-Upper half Nastran linear FEA model was used. PF1A coil modeled as discrete turns with insulating layers (CHEXA & CPENTA). Structural components modeled with plate elements (CQUAD4 & CTRIA3). Tie rods modeled with solid elements (CHEXA & CPENTA). Bolts modeled with CBAR elements attaching plates & adjacent weldments. EM loads on PF1A determined from dforce7b (Biot-Savart - U.C. code). Symmetry boundary conditions were applied (toroidal, vertical and rotational). Coil top & bottom surfaces not permitted to slide radially (rel. to supports). Model Summary: Number of GRID Points = 21979 Number of CBAR Element= 57 Number of CHEXA Elements= 13232 Number of CPENTA Elements= 1696 Number of CQUAD4 Elements = 2287 Number of CTRIA3 Elements= 170 Loading Conditions considered: Gravity, EM, Thermal, Seismic

13. FDR - Central Solenoid Support Structure - 9/6/06 3/4” Tie Rod / belleville washer, and bolted connection modeled

14. FDR - Central Solenoid Support Structure - 9/6/06 PF1A Coil Model: CPENTA & CHEXA isotropic Cu & Epoxy Glass

15. FDR - Central Solenoid Support Structure - 9/6/06 Loads considered: Gravity Loads with 1g & 2g vertical downward, B.C.: Symmetry & fixed at the upper bracket bolts (attached to the inner segmented ring castings which are assumed rigid). Horizontal seismic loading using static 0.15g acceleration per the NCSX/IBC2000 criteria (h~15ft, Fp=0.108 x 1.369 = 0.147 ~ 0.15g). B.C.: Symmetry & fixed @ upper bracket bolts. Thermally induced stress from cool down and temperature differentials using mean CTEs from R.T. to 77 o K. B.C.: Symmetry & fixed @ upper bracket bolts. (CTE-Cu from NIST data, CTE-304L from ITER data) Electro-magnetic loading for coil day-1 scenario A.1.3.2: I pf1a = 19,299 A & 23,500 A (simulates M.C. loading) I pf4 = 3,141 A I pf6 = 241 A I pl = -26,068 A & 0.0 A(I pl = 0.0 was highest loading) B.C.: Symmetry & fixed @ upper bracket bolts.

16. Vertical Displacements for a 1-g gravity: Max = 0.0025” FDR - Central Solenoid Support Structure - 9/6/06

17. Peak Tresca stress - 1-g loading: 3.44 ksi @ mtg. bolt holes Peak Tresca Stress: 3.44ksi

18. FDR - Central Solenoid Support Structure - 9/6/06 Vertical Displacements for (fault) 2g loading condition: -.005” max.

19. FDR - Central Solenoid Support Structure - 9/6/06 Tresca Z2 stress for a 2g loading condition (ie. if bottom supports loose or removed) Max Stress: 7ksi @ the mounting bolt holes

20. Lateral 0.15g seismic displ. 0.002” at the middle of the tierod Peak Tresca stress 2 ksi @ the bolt hole Seismic (static) load 0.15g horizontal acceleration with top mtg. bracket fixed Peak Tresca Stress 2.0ksi FDR - Central Solenoid Support Structure - 9/6/06

21. Thermal Loading: Coil @ 80K & Structure @ R.T.(extreme case) Max Vertical displacement: -0.085” @ the top of the coil

22. FDR - Central Solenoid Support Structure - 9/6/06 Need to avoid extreme thermal differentials during cooldown Peak Tresca Stress 78.6 ksi >> yield stress & allowable

23. FDR - Central Solenoid Support Structure - 9/6/06 A more realistic thermal loading assumes a temperature difference of 30 K and yields a relative vertical displacement of -0.012”. The differential rod & bellville to top plate shows about 0.005” - just over 50% of it’s linear range. ∂y ~0.005” ∂y (tot.): -0.0115”

24. FDR - Central Solenoid Support Structure - 9/6/06 Peak Tresca stress for a 30 K temperature differential: 15.6 ksi Peak Tresca: 15.6 ksi

25. FDR - Central Solenoid Support Structure - 9/6/06 Tresca Peak Stress is 4.6 ksi in coil insulation for 30 o K temperature differential

26. Baseline EM Loads assumed the 0.5T 1st Plasma Scenario Coil EM Loading No Plasma: Fr = 4,369 lbs/in [5,660 lbs/in * ] Fz = -3,722 lbs (total) [-6,355 lbs * ] DFORCE7b result: Hoop Stress(avg.)=1.27ksi [1.84ksi * ] Net Stress = 1.54ksi With I pl = -26,068 amps Fr = 4,318 lbs/in Fz = -3,647 lbs (total) DFORCE7b result: Hoop Stress (avg.)=1.25ksi Net Stress = 1.53ksi *For I pf1a = 23,500 Amps FDR - Central Solenoid Support Structure - 9/6/06

27. EM Loading was calculated as J x B body forces at each coil turn. Genforce subroutine added to DFORCE7b to generate Nastran Force input. Equivalent discrete forces for the worst cases were applied at each of 6 interior element grid points. Centroidal currents (@ each turn) were assumed. The loading from the M.C. field was simulated by running a 23.5 kA PF1a current case, which duplicates the peak vertical loading from the M.C. radial fields.

28. FDR - Central Solenoid Support Structure - 9/6/06 Typical EM grid point load resultants @ 6 interior points in conductor

29. FDR - Central Solenoid Support Structure - 9/6/06 Coil Displacements (SRSS) From 19.3kA EM Loads - No Axial Pre-load No Plasma -Maximum displacement was 0.0005” at the coil mid-plane Peak Displ. 0.0005”

30. FDR - Central Solenoid Support Structure - 9/6/06 Peak Tresca stress in the coil from 19.3kA EM loading only: 1.83 ksi Peak Tresca: 1.83ksi

31. Peak Tresca Stress in supports 19.3kA EM + Thermal (cool-down): 14.0 ksi (with CONROD elements at bolt hole perimeter) FDR - Central Solenoid Support Structure - 9/6/06

32. Peak Tresca Stress in supports 19.3kA EM + Thermal (cool-down): 2.51 ksi (with MPCs replacing CONROD elements at bolt hole perimeter)

33. FDR - Central Solenoid Support Structure - 9/6/06 Peak Tresca Stress in Coil for 23.5 kA EM-only loading, 2.78 ksi (Loading includes the effects of the M.C. peak fields) Peak Tresca Stress in Cu 2.78 ksi

34. FDR - Central Solenoid Support Structure - 9/6/06 Peak Tresca Stress in Support for 23.5 kA EM loading, 3.68 ksi

35. FDR - Central Solenoid Support Structure - 9/6/06 Peak Tresca Stress in coil insul. for 23.5 kA EM-Cold loading, 3.17 ksi, 2.9 ksi in Cu Peak Tresca Stress: 3.17 ksi Peak Cu Tresca Stress: ~2.9 ksi

36. FDR - Central Solenoid Support Structure - 9/6/06 Displacements for combined gravity, thermal, EM loading Peak Displ. 0.167” (SRSS)

37. FDR - Central Solenoid Support Structure - 9/6/06 Tresca stress in coil from combined gravity, thermal, and EM loading Peak Tresca Stress = 3.16 ksi - insulation Average coil Tresca stress ~2-3ksi

38. FDR - Central Solenoid Support Structure - 9/6/06 Peak Tresca Stress 2.68 ksi Peak Stress in supports from combined gravity, thermal, and EM load

39. *Allowable 304L @ 80 o K = 46.6 ksi (321 MPa) (2/3 rd yield criteria) Allowable CDA107(10%CW) Cu @ 80 o K = 16 ksi (110.6 MPa) (2/3 rd yield criteria) ** Allowable CTD112P-w/Kapton @ 80 o K = 8.86 ksi (61.3 Mpa 2/3 rd ultimate criteria) -per ITER test data § Actual margins on max shear are double these values (C 2 = 0.6, S c = 0.0 - Eqn. From NCSX design criteria, 5.6 ksi no compr.) **Sy = 124 - 0.241xT +14.1xCW - 0.166xCW 2 = 230.5MPa, 2 x sigma = 64 MPa, 230 - 64 = 166, 2/3 x 166 = 110.6 MPa (16 ksi) (From NIST Monograph 177 -Simon, Drexler, Reed) FDR - Central Solenoid Support Structure - 9/6/06 Load caseMax. Displ. (inch -SRSS) Suppt. Coil Max Tresca Stress -ksi Suppt. Coil Location Suppt. Coil Margin on Allowable* Suppt. Coil Gravity-1g Seismic 0.0025 v 0.002 h < 0.0002 h 3.44 negl. 2.0 negl. mtg.brkt __ Rods __ 13.5 __ 23.3 __ Thermal (∂30 o K) 0.0112 0.00515.6 3.3 Cu 4.6 (ins.) @bolts corners3.0 4.84 1.9/1.2 § EM (23.5kA) 0.0005 0.00053.68 1.83@bolts mid-coil12.6 12.3/8.7 EM + 1g + cooldown 0.167 0.0695 (SRSS) 2.68 2.9-Cu 3.16-ins. @bolts mid-coil outer c. 17.4 5.5 2.8 Stress Analysis Summary

40. Coil Testing Requirements: Electrical After re-configuring and re-insulation of coolant tubes, coils will require a hi-pot to ground at 2 kV (2 x V op. +1000) and a megger at room temperature and 80 deg.K. Insulating breaks between field periods will be meggered @ 2kV Mechanical During cool-down for 80 deg.K electrical test, a flow measurement for a delta-P of 10psi will be required. Thermocouples on inlet and outlet tubes will be needed to provide a record of T vs. time for the cool-down. FDR - Central Solenoid Support Structure - 9/6/06

41. Cost & schedule: Build in-house preliminary est: ~75k$ Will issue an RFQ for 304L & 316L by late Sept.’06 Anticipate a 4-6mo. Delivery A 316L material may delay things a month or two and may cost 30% more.

42. FDR - Central Solenoid Support Structure - 9/6/06 Conclusions: Charge: Does the coil structure provide adequate support for the PF1a coils with sufficient margins of safety? A: Stress margins on allowables for both coil and support exceed project & code requirements. Have the interfaces with other sub-systems been defined and are they compatible? A: Interfaces to machine structure, cryo-system, and electrical power defined & compatible. Are the drawings and supporting documents complete and ready for sign-off? A: Drawings & BOM are complete and ready for checking/sign-off. Has the analysis been documented and checked? A: The stress & thermal analysis have been documented & are being checked. Are the cost, procurement and assembly schedule consistent with the program schedule and budget? A: Cost & schedule are consistent with project schedule and, pending responses from RFQ, should fall within the current project budget.

43. FDR - Central Solenoid Support Structure - 9/6/06 per A.Brooks 9/1/06

44. FDR - Central Solenoid Support Structure - 9/6/06

45. Fatigue analysis: 304L Peak Tresca Stress: 15.6 ksi (EM + 1g + 30 o K delta) Operating stress below the  /2 @ 130,000 cycles The 2/20 project criteria for fatigue is satisfied although the anticipated usage of the PF1a coils and supports is significantly less than the 130,000 cycles. 20x life 15

46. Shear Strength CTD112P (w/Kapton) 13.3 ksi @77 deg.K FDR - Central Solenoid Support Structure - 9/6/06

47. ITER shear-compression tests Max Shear: 6.78 ksi for 15 degree angle(12ksi compr.) @ 77 deg. K FDR - Central Solenoid Support Structure - 9/6/06 6.7 ksi 40 MPa, 5.8 ksi-static & fatigue

48. FDR - Central Solenoid Support Structure - 9/6/06 Inner radial stop will maintain central alignment of PF1a coils