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 Build Disruption 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 Analysis Maxwell /Ansys Analyses by A. Zolfaghari

EM Analysis B Fields Body Forces on TF 13.97T

Structural Analysis

Toms AT Structural Analysis Casing & Inter-coil Structure Stress Winding Pack Stress

7 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 with ITER TF Orthotropic Properties ITER grade inner TF casing SS 316 primary membrane stress allowable Equivalent Stress in the Inner TF Leg Nose Table ITER TF Orthotropic smeared Material Properties of the TF Coil Winding Pack Used in 3D Global Non-linear Model Ex 61.7 GPa NUxy Ey 101. GPa NUyz Ez 49.4 GPa NUzx Gxy 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 direction 2) 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 MPa LOW CYCLE OR NO FATIGUE ITER TF Orthotropic Properties

Bucked (JET, ITER-Rebut), Poloidal Plates ITER Wedged Only with Radial PlatesPPPL AT PILOT Rectangular Bent Tube Conductor Inner Leg TF Support Structures Other Possibilites: Bucked and Wedged Square Extruded Conductors

Volumes 1 cm slice Mat 1 Jackets e-3 m^3 Mat 2 Superconductor 1.442e-3 m^3 Mat 5 Insulation 6.259e-4 m^3 Mat 10 Case 1.798e-3 m^3 Winding Pack 3.386e-3 Total e-3 m^3 Winding Pack Metal Fraction = 39% Ansys Analyses by P. Titus With no Vertical Tension (yet) Fields 2D 11.3T 3D 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 Allowable Use Rings to keep Corner Closed – And “Pinch” Inner Leg and Off Load Vertical Tension

18 NSTX Disruption Model Beginnings 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