FDR - NCSX Central Solenoid Support Structure Fred Dahlgren Joe Rushinski 6 Sept 2006
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Transcript of FDR - NCSX Central Solenoid Support Structure Fred Dahlgren Joe Rushinski 6 Sept 2006
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
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 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
FDR - Central Solenoid Support Structure - 9/6/06
PF1a Coil/Structure Assembly - Pre-assembled
FDR - Central Solenoid Support Structure - 9/6/06
111.5”
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 plates @ 120 deg.
G10/11CR washers & bushings
Copper tubing
Brass Swagelok (B-600 series) tube fittingsInterfaces:
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.
FDR - Central Solenoid Support Structure - 9/6/06
*
* From Allegheny Ludlum Technical Data Blue Sheet
2/3rd Yield allowable @80K = 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.
0.787
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 = 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
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 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 oK. 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: Ipf1a = 19,299 A & 23,500 A (simulates M.C. loading)Ipf4 = 3,141 AIpf6 = 241 AIpl = -26,068 A & 0.0 A(Ipl = 0.0 was highest loading)
B.C.: Symmetry & fixed @ upper bracket bolts.
Vertical Displacements for a 1-g gravity: Max = 0.0025”
FDR - Central Solenoid Support Structure - 9/6/06
FDR - Central Solenoid Support Structure - 9/6/06
Peak Tresca stress - 1-g loading: 3.44 ksi @ 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: 7ksi @ the mounting bolt holes
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
FDR - Central Solenoid Support Structure - 9/6/06
Thermal Loading: Coil @ 80K & Structure @ R.T.(extreme case)
Max Vertical displacement: -0.085” @ 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 -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”
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 oK 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 Ipl = -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 Ipf1a = 23,500 Amps
FDR - Central Solenoid Support Structure - 9/6/06
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 resultants @ 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 0.0005” at the coil mid-plane
Peak Displ. 0.0005”
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
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
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Displacements for combined gravity, thermal, EM loading
Peak Displ. 0.167” (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 304L @ 80 oK = 46.6 ksi (321 MPa) (2/3rd yield criteria)
Allowable CDA107(10%CW) Cu @ 80 oK = 16 ksi (110.6 MPa) (2/3rd yield criteria) **
Allowable CTD112P-w/Kapton @ 80 oK = 8.86 ksi (61.3 Mpa 2/3rd ultimate criteria) -per ITER test data
§ Actual margins on max shear are double these values
(C2 = 0.6, Sc= 0.0 - Eqn. From NCSX design criteria, 5.6 ksi no compr.)
**Sy = 124 - 0.241xT +14.1xCW - 0.166xCW2 = 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 case Max. 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 0.0025 v
0.002 h < 0.0002 h
3.44 negl.
2.0 negl.
mtg.brkt __
Rods __
13.5 __
23.3 __
Thermal (∂30 oK)
0.0112 0.005 15.6 3.3 Cu
4.6 (ins.)
@bolts corners 3.0 4.84
1.9/1.2§
EM (23.5kA) 0.0005 0.0005 3.68 1.83 @bolts mid-coil 12.6 12.3/8.7
EM + 1g
+ cooldown
0.167 0.0695
(SRSS) (SRSS)
2.68 2.9-Cu
3.16-ins.
@bolts mid-coil
outer c.
17.4 5.5
2.8
Stress Analysis Summary
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are needed to see this picture.
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 Vop. +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
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
PF1a Radial Running Load
855000
860000
865000
870000
875000
880000
885000
890000
895000
900000
905000
0 60 120 180 240 300 360
Angle, deg
Running Load, N/m
PF1a OnlyPF1a + PF4&6
PF1a,4,6 & Mod
per A.Brooks 9/1/06
PF1a Vertical Running Load
-30000
-25000
-20000
-15000
-10000
-5000
0
0 60 120 180 240 300 360
Angle, deg
Running Load, N/m
PF1a OnlyPF1a + PF4&6
PF1a,4,6 & Mod
per A.Brooks 9/1/06
FDR - Central Solenoid Support Structure - 9/6/06
FDR - Central Solenoid Support Structure - 9/6/06
Fatigue analysis:
304L Peak Tresca Stress: 15.6 ksi (EM + 1g + 30 oK delta)
Operating stress belowthe /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
Shear Strength CTD112P (w/Kapton) 13.3 ksi @77 deg.K
FDR - Central Solenoid Support Structure - 9/6/06
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
FDR - Central Solenoid Support Structure - 9/6/06
Inner radial stop will maintain central alignment of PF1a coils