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

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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

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(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

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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

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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

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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

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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

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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

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/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

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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?

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ITER IVC IDR 26-28 July 2010

In-Vessel Coil System Conceptual Design Review – 29-30 September, 2009 29

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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