AT Pilot Plant EM and Structural Studies
P. Titus
Goals of the PPPL AT Pilot Plant EM and Structural Studies
Basic Sizing and Stress Analysis of the TF Case and Winding Pack Including OOP
Show Non-Constant Tension D is Acceptable – Provides more Effective PF Usage. Reduces Mass of the Machine, Increases Peak Field
Study Inner Leg Winding Pack Cross Sections and Jacket Shapes Rectangular vs. Circular, Radial Plates, Extruded Square Conductor
Study Inner TF Support Concepts Wedged Only Bucked Bucked and Wedged
Heat Balance
Re-Position the Joints to the Bore? – Saves Radial BuildDisruption Simulations of Tom’s in-Vessel Structures
Geometry and Currents 30-degree slice modeled with one TF coil TF current= 10MA per leg PF &OH Currents from TSC code:
AT Pilot Plant TF Structural AnalysisMaxwell /Ansys Analyses by A. Zolfaghari
EM AnalysisB Fields
Body Forces on TF
13.97T
Structural Analysis
Toms AT Structural AnalysisCasing & Inter-coil Structure Stress Winding Pack Stress
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AT pilot plant device core (AT PILOT PLANT DEVICE CORE)
(Tom Browns’s 2012 Vertical/Servicing Access Concept)
Case Bending Stress Resulting from Deviation from Constant Tension D, Allowing PF Coils to be Closer to the Plasma
Model With Symmetry Expansion
Ali’s Model has Heavier Case Structures that Resist Bending
Equivalent Stress with ITER TF Winding Pack Orthotropic Properties
Wedging and Nose Compression Plus Vertical Tension
Max Principal Stress with ITER TF Winding Pack Orthotropic Properties
Mostly Vertical Tension From Vertical Separating Force
Stress withITER TF OrthotropicProperties
ITER grade innerTF casing SS 316primary membrane stress allowable
Equivalent Stress in the Inner TF Leg Nose
Table 2.2.3-1 ITER TF Orthotropic smeared Material Properties of the TF Coil WindingPack Used in 3D Global Non-linear ModelEx 61.7 GPa NUxy 0.237Ey 101. GPa NUyz 0.241Ez 49.4 GPa NUzx 0.161Gxy 27.7 GPa ax (for 293K to 4K) 0.304%Gyz 22.8 GPa ay (for 293K to 4K) 0.299%Gxz 6.68 GPa az (for 293K to 4K) 0.319%1) x = radial direction, y= poloidal (winding) direction , z = toroidal direction2) In the finite element code used Poisson’s ratio may be input in either major (PRxy, PRyz, PRxz) minor (NUxy, NUyz, NUxz) form
Static Membrane Allowable = 2/3*1000MPa = 660 MPaLOW CYCLE OR NO FATIGUE
ITER TF Orthotropic Properties
Bucked (JET, ITER-Rebut), Poloidal Plates
ITER Wedged Only with Radial Plates PPPL AT PILOT Rectangular Bent Tube Conductor
Inner Leg TF Support Structures
Other Possibilites: Bucked and Wedged Square Extruded Conductors
Volumes 1 cm sliceMat 1 Jackets 1.318 e-3 m^3Mat 2 Superconductor 1.442e-3 m^3Mat 5 Insulation 6.259e-4 m^3Mat 10 Case 1.798e-3 m^3Winding Pack 3.386e-3Total 5.183 e-3 m^3
Winding Pack Metal Fraction = 39%
Ansys Analyses by P. Titus
With no Vertical Tension (yet)
Fields2D 11.3T3D 13.89 T
Forces
Tresca – With no Vertical Tension (yet)
Hoop Stress
Add ~390 Mpa Vertical Tension, Total is ~700 MPa
Note that a Big Contribution to the Inner Leg Stress is the Vertical Separating Force, Which is Driven by External Structures and
Where you Put the TF Outer Leg
FIRE Simulation Model
Using the External Structures Limit Analysis to Allow Other than Membrane Stress AllowableUse Rings to keep Corner Closed – And“Pinch” Inner Leg and Off Load Vertical Tension
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NSTX Disruption ModelBeginnings of the AT Pilot Plant Disruption Model
Current Densities in the Whole Model NSTX Including the TF
Transient Thermal Analyses of the Tokamak Internal Components
MIT Hot Divertor Collaboration(By H. Zhang, P.Titus)
NSTX Global Heat Balance Calculations(By A. Brooks)
• 16 mm OD Superconducting Cable Modeled as petal and sub-petal with pitches of .45m and .25m
• SC space filled with conductive material (hole not modeled)
• 1mm Braze layer• 1mm SC lacing layer with pitch same as petal
pitch .45m• 6mm Outer Shell• Joint 0.25m long• Unit resistivity (1nOhm-m) used for all
transverse conduction
• Same 16 mm OD Superconducting Cable Modeled as petal and sub-petal with pitches of .45m and .25m
• SC space filled with conductive material (hole not modeled)
• Sole Plate 50mm wide, 30mm thick, .45m long (1 pitch length)
• Cables 31mm center to center• Unit resistivity (1nOhm-m) used for all
transverse conduction
ITER CS Coax Joint Model
ITER CS Twin Box Joint Model
We are Currently Analyzing ITER Joint Concepts for Outside the CS. If the AT has a low enough Bdot in the Bore – The Joints may be able to be located in the Bore. A. Brooks is Qualifying .22T/sec Radial Bdot for ITER
Pilot Plant CS Fields. Peak = 9.7T