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

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?

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

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 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 ” O.D ” axial length 48 turns Cu area: 0.52 sq.in. Hole dia.: 0.354” Leads: 12.6” & 16.9” Fabr. Details see: NSTX-SPEC

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

FDR - Central Solenoid Support Structure - 9/6/ ”

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

Materials: 304L solution annealed plates ER316LN weld filler 316L nuts, bolts, washers, & rods G10/11CR insulating 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 defines the current & voltage requirements. Top & bottom mounting pads bolt to same threaded holes to be used for permanent solenoid supports. support interface defined.

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

2/3rd Yield = 46.6ksi 304L Properties* * From Allegheny Ludlum Technical Data Blue Sheet

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 Ø 0.354

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 = Number of CBAR Element= 57 Number of CHEXA Elements= Number of CPENTA Elements= 1696 Number of CQUAD4 Elements = 2287 Number of CTRIA3 Elements= 170 Loading Conditions considered: Gravity, EM, Thermal, Seismic

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

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

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 = ~ 0.15g). B.C.: Symmetry & 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 & 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 & upper bracket bolts.

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

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

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

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: the mounting bolt holes

Lateral 0.15g seismic displ ” at the middle of the tierod Peak Tresca stress 2 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

Thermal Loading: 80K & R.T.(extreme case) Max Vertical displacement: the top of the coil

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

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 ”. The differential rod & bellville to top plate shows about 0.005” - just over 50% of it’s linear range. ∂y ~0.005” ∂y (tot.): ”

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

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

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

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.

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

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 ” at the coil mid-plane Peak Displ ”

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

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

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

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

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

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

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

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

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

*Allowable 80 o K = 46.6 ksi (321 MPa) (2/3 rd yield criteria) Allowable CDA107(10%CW) 80 o K = 16 ksi (110.6 MPa) (2/3 rd yield criteria) ** Allowable 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 = Eqn. From NCSX design criteria, 5.6 ksi no compr.) **Sy = xT +14.1xCW xCW 2 = 230.5MPa, 2 x sigma = 64 MPa, = 166, 2/3 x 166 = 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 v h < h 3.44 negl. 2.0 negl. mtg.brkt __ Rods __ 13.5 __ 23.3 __ Thermal (∂30 o K) Cu 4.6 corners /1.2 § EM (23.5kA) mid-coil /8.7 EM + 1g + cooldown (SRSS) Cu mid-coil outer c Stress Analysis Summary

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 ) and a megger at room temperature and 80 deg.K. Insulating breaks between field periods will be 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

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.

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.

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

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

Fatigue analysis: 304L Peak Tresca Stress: 15.6 ksi (EM + 1g + 30 o K delta) Operating stress below the  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

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

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

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