PF Coil 2-6 Supply. Main technical aspects. P. Valente

PF Coil 2-6 Supply Main technical aspects P. Valente PF Coils EI Information Meeting Cadarache, 19 February 2013 This presentation is intended for reference purposes only and is not a legally binding document Contents Introduction (Technical Specification) Slide 2

ITER Machine Introduction Context; PF Coils within ITER machine ITER Poloidal Field Coils Slide 3 ITER PF Magnet System Introduction 6 coils Main Features: ~1 m Circular coils Supported on TF DP 2-in-hand windings RF: PF1 EU: PF2~PF6 Slide 4

PF Coils Parameters Introduction PF2 PF3 PF4 PF5 PF6 Maximum oper. current per turn (ka) 55 55 55 52 48(52) Coil current capacity (MA*turns) 6.32 10.22 9.34 11.28 22.0(23.88) He temperature (K) 4.2 4.2 4.2 4.2 4.2(3.8) Peak magnetic field (T) 4.8 4.8 4.8 5.7 6.4(6.8) Maximum operating terminal voltage (including 10.5 10.5 10.5 10.5 11 fast discharge, kv) Turn-to-turn (radial) maximum operating voltage 0.88 0.66 0.66 0.66 0.61 (kv) Terminal voltage (kv) 23.2 23.2 23.2 23.2 18.9 in faulted operation Test DC Voltage (kv) Ground to Terminal 24.2 24.2 24.2 24.2 23 Slide 5 Weight of PF coils Introduction (Unit : ton) PF coil NbTi Strand Conductor Winding Pack Clamps + protection cover + spacers Total PF2 19 110 122 82 204 PF3 45 257 283 101 385 PF4 41 234 258 92 350 PF5 44 211 231 110 342 PF6 61 242 262 134 396 32% Contribution of main components per coil, averaged 6% 62% Conductor 32% 62% Insulation and resin 6% Clamps + protection cover + spacers Slide 6

ITER PF Magnet System Scope Project Scope Supply of the Poloidal Field Coils (PF2-PF6 Coils) of the ITER magnet system To make a cold test at 77 K on all the coils ITER Supply (free issue mat.) Conductors Clamps Manufacturing in PF Building in Cadarache France (due to the big size) The project is composed of several primary work packages, each of which is envisaged to be carried-out by parties drawing upon their specialist strengths under one or more contract Auxiliary equipment Slide 7 ITER PF Magnet System Scope Coil Manufacture at ITER site in Cadarache, France PF Coil Building, completed April 2012 Slide 8

Main Concept Operating field at PF coils is relatively low, i.e. with respect to TF (<7T) -> NbTi conductor was chosen 2-in-hand: PF coils are wound as two overlapping pancakes forming together one double pancake He inlets are at inner turns of each DP Double pancakes are arranged with accessible joints on outside and preinstalled jumper cables Large forces -> Robust structural components: Stainless Steel Jackets are used for the superconductor, designed to operate at high operating fields and for a large number of cycles (60,000) -> Large steel fabrication (welding, forging, etc.) with tight tolerances Slide 9 Double Pancake Cooling Scheme o o o 2-in-hand for all PF coil He inlet in the vertical joggle and inner radius He outlet in the joint area. It is in the middle of each conductor length, sharing equally the helium path. Slide 10

let and outlet To bus bar Terminal DP1 Joint inlet DP2 To DP3 Cooling pipe inlets and outlets must contain an electrical insulating break ITER free items (epoxy or ceramic-based) capable of supporting the ground potential of the coil To be welded to the supply pipes Slide 11 Double Pancake Parameters Total conductor length, incl. joints and terminals (m) Conductor unit length supplied (m) Number of unit lenght Number of Turns Nr Nz, Total PF2 6009 517 12 ( 2 x 6) 115.2 PF3 14067 894 16 (2 x 8) 185.9 PF4 12835 817 16 (2 x 8) 169.9 PF5 11487 737 16 (2 x 8) 216.8 PF6 12670 718 18 (2 x 9) 459.4 Slide 12

Terminal Connection Thermal contraction (when coil cool down to 4K) and EM forces are acting on the terminals The terminal box is designed to carry and transfer the load to the winding pack and it also needs to be electrically isolated Heavy components, some with tight tolerances The terminal box consists of spacer, can, central plate, central isolation plate and clamp for He pipe and twin box joint. Slide 13 Coil Jumpers If fault appears during the operation due to: Electrical short between the two conductors Helium leak through Jacket or joint Box the faulted DP joints (on the coil outer radius) to be disconnected the jumpers cables to be brought and connected to the remaining good DPs. The joint insulation and helium pipes to be Rebuilt/checked All the activity needed in case a fault are out of the scope of the project. Slide 14

Clamp & Protection cover Coil clamps, ~1 m wide (~ 4.8 T for PF5), are equally spaced around the winding pack. Only their assemblies are in the scope of the project (they will be provided by China Domestic agency) The winding body with ground insulation, high potential cooling pipes from all joints and terminations of the coil are covered by a grounded protection cover (included in the scope) The protection covers consists of section of rectangular box of 304L steel, which surrounds the four sides of the coils between the PF clamp supports. Protection cover support clamps Slide 15 Auxiliary equipment Several types of auxiliary equipment will be provided by ITER Organization and so only their assembly is in the scope of the project: Insulation breaks Protection resistors for voltage taps Low voltage cable connectors Temperature sensors Pressure sensors Slide 16