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