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Vertical Stability Coil Structural Analyses. P. Titus, July 27 2010. Criteria for IV Coils Will be Appendix D of the In-Vessel Component Criteria. Copper:. This will be Fatigue Driven. Primary Loads are Supported by the Case, Thermal Stresses are Self Relieving - PowerPoint PPT Presentation
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In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 1
Vertical Stability Coil Vertical Stability Coil Structural AnalysesStructural Analyses
P. Titus, July 27 2010
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 2
2
Material Sm 1.5Sm
316 LN SST 183Mpa (26.6 ksi) 275Mpa
(40ksi)
316 LN SST
weld
160MPa(23.2ksi) 241MPa(35ksi)
Criteria for IV Coils Will be Appendix D of the In-Vessel Component Criteria
Copper:
Stainless Steel:
This will be Fatigue Driven. Primary Loads are Supported by the Case, Thermal Stresses are Self RelievingFailure is Leak Due to Crack Propagation
Also Fatigue Driven, but Must Support Primary Loads
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 3
3
(257.2-212)* 5/9=25.1 deg C
Joule Heating Loads(M. Mardenfeld Early Results)
Latest results are the same or less than 25deg C except the double turn failure results.
Charlie’s Design Point is now 20 deg
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 4
Structural Model FeaturesStructural Model Features
4
Model is a 10 degree cyclic symmetry model
Coils are supported every 5 degrees with ClampsTemperatures modeling the Joule heat and nuclear heat Based on Nuclear Heat from Russ Feder
Radial forces are computed from SQRT(1.2) MN/40 degree sector.
Vertical forces are computed from SQRT(1.2) MN/40 degree sector
Radial and Vertical Forces are applied concurrently
Sliding gap-friction is modeled between Spine, Sheath, MgO and conductor.
A Retainer Clamp is Used Rather than Weld or Braze.
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 5
55
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009
The 2D model is swept through 10 degrees. Then regions between clamps and bolts are deleted to form the model.
Present Design IterationMesh Generation
“Feet” Modeling Welds and Vessel Connection
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 6
6
VS StructuralModel
Gap Elements between all MgO conductor Components
SST “Spine”
Displacement Constraints Model Cyclic Symmetry
Gap Elements at Clamps
In-Vessel Coil System Pre-Preliminary Design Review – 26-27 July 2010 7
Temperature from Joule Heat/Water Cooling input as a Boundary Condition
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 8
8
Nuclear Heat taken from Russ Feder’s CalculationTemperatures are calculated from a Steady State Heat Conduction Analysis
In-Vessel Coil System Pre-Preliminary Design Review – 26-27 July 2010 9
Modeling Nuclear Heat
In-Vessel Coil System Pre-Preliminary Design Review – 26-27 July 2010 10
Electromagnetic Loads
VSFORCE= 1.1526e6**.5Some Analyses Still Use the Previous 2 MN in Each Direction
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 11
Disruption Inductively Driven Electromagnetic Disruption Inductively Driven Electromagnetic LoadsLoads
11
Around the upper VS ELM the vessel current density is 10 amps per mm^2 with the case
If the current density is the same in the case as in the vessel, The case currents are as high as 10*20231=202kA
Currents are comparable to Nominal 240kA currents – Thus forces are.
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 12
12
/solubfe,all,temp,1,380 !100Cesel,real,11,14 $nelembfe,all,temp,1,400 ! Conductors 20C hotterNall $eallSolve $save/title, Disruption + Normal Operating Loads 2e6/40degesel,mat,1 $nelemf,all,fz,vsforce/4/46656 ! there are 29160 nodes in the conductors and 2e6 is for 40 degreesf,all,fx,-vsforce/4/46656Nall $eallSolve $save/title, Disruption + Normal Operating Loads +Nuclearldread,temp,last,,,,therm,rthNall $eallSolve $save/title, Lorentz+Shared Ves Disrup Current + Normal Operating Loads 2*2e6/40degesel,mat,2 $nelemf,all,fz,2*vsforce/4/52486f,all,fx,-2*vsforce/4/52586Nall $eallSolve $saveFini $/exit
1.2e6 N per 40 degree sector Vector Sum of Radial and Vertical Directions are used
An additional 1.2e6 N Vector Sum of Radial and Vertical Directions are applied on the case to simulate loads from shared vessel currents
LDREAD Temps from Nuclear Radiation Thermal Analysis
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 13
M25 Bolts – Bolt Preload + Joule Heat Load Step
~100 MPa Bolt Preload
~400 MPa Preload Eliminated Clamp Lift-Off
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 14
CDR Model Response, No Shared Vessel CurrentsCDR Model Response, No Shared Vessel Currents
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 15
CDR Model Response, With Shared Vessel CurrentsCDR Model Response, With Shared Vessel Currents
In-Vessel Coil System Pre-Preliminary Design Review – 26-27 July 2010 16
PDR Model Response, With Shared Vessel CurrentsPDR Model Response, With Shared Vessel CurrentsLower Bolt Preload is RequiredLower Bolt Preload is Required
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 17
With the Full Current Inventory (1.2MN/40deg) in With the Full Current Inventory (1.2MN/40deg) in Conductors and Spine, Stresses in the Spine are Conductors and Spine, Stresses in the Spine are
AcceptableAcceptable
Material Sm 1.5Sm
316 LN SST 183Mpa (26.6 ksi) 275Mpa
(40ksi)
316 LN SST
weld
160MPa(23.2ksi) 241MPa(35ksi)
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 18
Conductor StressesConductor Stresses-Will be qualified by fatigue analysis-Will be qualified by fatigue analysis
Conductor Stress With Joule Heat
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 19
Conductor StressesConductor Stresses-Will be qualified by fatigue analysis-Will be qualified by fatigue analysis
These Results are for the CDR 2MN Loading in Each Direction
Conductor Stress With Joule Heat and Normal Operating Lorentz Loads
Tensile Stresses are Low
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 20
Weld Stresses at the Clamp BodyWeld Stresses at the Clamp BodyCDR Design at 2MN – Design Similar to PDR CDR Design at 2MN – Design Similar to PDR
DesignDesignThe peak weld stress of ~70 MPa tension is modest. It will provide some headroom for fatigue evaluations.
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 21
Weld Stresses Weld Stresses CDR Design at 2MN – Design Similar to PDR CDR Design at 2MN – Design Similar to PDR
Loads Per 10 Degree Model Section, Summed Over All All WeldsLOAD STEP= 4 SUBSTEP= 1 TIME= 4.0000 LOAD CASE= 0 THE FOLLOWING X,Y,Z SOLUTIONS ARE IN THE GLOBAL COORDINATE SYSTEM FX FY FZ
Radial Vertical ToroidalTOTAL VALUES 0.93804E+06 -0.10195E+07 12.464
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 22
Peak Clamp to Vessel Weld Peak Clamp to Vessel Weld Stress CDR Design at 2MN – Stress CDR Design at 2MN –
Design Similar to PDR Design Similar to PDR
Material Sm 1.5Sm
316 LN SST
183Mpa (26.6 ksi)
275Mpa
(40ksi)
316 LN SST
weld
160MPa(23.2ksi)
241MPa(35ksi)
Peak Weld Stress Meets “Average” Static Stress Criteria
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 23
Mounting Mounting Bolt StressBolt Stress
With With Adequate Adequate
Preload (400 Preload (400 MPa), The MPa), The
Bolt Bolt Alternating Alternating Stress is Stress is
Low. Low.
In-Vessel Coil System Pre-Preliminary Design Review – 26-27 July 2010 24
Joggle ModelJoggle Model
In-Vessel Coil System Pre-Preliminary Design Review – 26-27 July 2010 25
Only Copper is Modeled
Only Toroidal Field is Applied
Fixity is assumed where the conductor enters the splines
Turns need to be shortened to Reduce the length that crosses the toroidal field
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 26
VS Fault Conditions (OneD Analysis)Only Radiative Cooling, 20 Minute Cooldown Between Pulses
Tube Surface Temp Radiating to 373K, Tube emissivity =.3, Vessel emissivity =.8, Nuclear Heat = 1.4MW/m^3, Tube Thickness = 1.9mm
500 sec
1000 sec
1500 sec
650 K
875K
1050K
Stresses Due to These TBD
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 27
27
Conclusions
The VS coil conceptual design is In a comfortable design space to finish preliminary and go forward final design
Conductor thermal stresses are low because of the axisymmetry of the winding (no corner bends as in the ELM). Lead break-outs will have to preserve this feature
Case stresses are high under the clamp details but with some slight modifications, these will meet static and fatigue allowables.
Bolt stresses during the disruption are within the allowables of high strength bolts. Preloading the bolts eliminates the alternating component.
Assuming shared vessel currents during the disruption, may be overly conservative. Should current density be halved?
Does Proximity to the ELM Coils Still Make the Clamp Bolting Challenging – Investigate Common ELM/VS Clamps?
VS Issues and Resolution PlanIssue Resolution Pre/Post
October
PDR Interpretation of Loading (1.2MN Vector Sum) is Lower than CDR Shared Current Loads Are also lower because they are assumed comparable
Resolve Interpretation of Loads Pre
Conductor thermal stresses are low because of the axisymmetry of the winding (no corner bends as in the ELM). Lead break-outs will have to preserve this feature
Interaction of conductor, MgO and Sheath at Lead Break-outs is very similar to elm coil corners – Will have a common solution/qualification.
Pre
“bump” over the lead break-out and the leads crossing the TF field will need supports at shorter spans
Add brackets as required . Pre
Uncertainty in MgO properties and behavior
Characterization of MgO from testing underway needs to be folded into analysis
Pre?
28
ITER IVC IDR 26-28 July 2010
In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 29
29
Poloidal Force Per 40 degrees sector 2.00E+06 NRadial Force Per 40 degrees sector 2.00E+06 NPoloidal Force Per 10 degrees sector 5.00E+05 NNormal Force Per 10 degrees sector 5.00E+05 NNumBolts per 10 degree Sector 12Conductor Centroid Height From Flange 90 mmCase Base Width 175 mmDiameter of Bolt 25 mmFlng contact to Bolt CL 25 mmFlng Contact to Clamp Edge 47 mm
Clamp Force Due to Normal Load per Bolt 4.17E+04 NClamp Force Due to Poloidal Load per bolt 4.29E+04 NTotal Clamp Force 8.45E+04
Clamp CalculationsPrying Moment 3.97E+06 N-mmBolt Load 180573.6 NBolt area 490.875 mm 2̂Bolt Stress 367.8606 Mpa
Clamp Bolt Stress
Comparable to FEA Results