An Overview of the EAST Project

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EAST
ASIPP
An Overview of the EAST Project
Songtao Wu and the EAST Team Institute of Plasma
Physics, Chinese Academy of Sciences, P.O. Box
1126, Hefei, Anhui, 230031, P.R. China 1.
Introduction 2. Tokamak Machine and Key
Technologies 3. Results of the First
Commissioning 4. Future Plan 5. Summary

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1. Introduction

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The EAST National Project of China The
Experimental Advanced Superconducting Tokamak
(EAST) project was approved in 1998 by the China
government and began construction in 2000.

• The Scientific and Engineering Missions of
  the EAST Project are
• to study physical issues of the advanced
  steady-state operation modes
• to establish technology basis of full
  superconducting tokamaks for future reactors

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cryogenic and refrigerator system
Power supply system
Vacuum pumping and gas puffing system
Diagnostic system
Superconducting Tokamak Machine
The main construction tasks of the project
Experimental Hall
Test Facility System
Control and data processing system
Non-inductive current drive and heating system
Water cooling system

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Main Parameters of the EAST Nominal Upgrade B
o 3.5 T 4.0 T IP 1 MA 1.5 MA Ro 1.7
m 1.7 m a 0.4 m 0.4 m R/a 4.25 4.25 Kx
1.2-1.5 1.5-2 dx 0.2-0.3 0.3-0.5 Heating
and Driving ICRH 3 MW 6 MW LHCD 3.5 MW 8
MW ECRH 0.5 MW 1.5 MW NBI 8 MW Pulse
length 1000 s Configuration Double-null
divertor Single-null divertor

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The EAST machine assembly has been pre-completed
in Jan. 2006. The first engineering commissioning
began from Feb. 7, 2006 and finished on Mar. 17.

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• On Mar. 4 all superconducting coils were cooled
  down to lower than 4.5K.

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• Total 260 shots have been energized. The longest
  TF current duration was 5000 s and the highest TF
  current was 8200A.

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ICRH LHCD system
CICC large scale magnet
Control data acquisition system
Most of key technologies are developed in ASIPP
Vacuum pumping system
SC magnet test facility
210MW Power supply system
2kW/4.5K Cryogenic refrigerator system

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2. Tokamak Machine and Key Technologies

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Main Components of the EAST Machine

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Cryostat
Thermal Shield
Central Solenoid
PF Coils
Vacuum Vessel
TF Coils
EAST Device Height10 m Diameter8 m Weight414
ton
Supports of TFPF
Main Support

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3 Tangential Ports
8 Standard Ports
Final VVTS Section Assembly
5 Big Ports
Final TF Assembly
Top View and Ports Arrangement of EAST

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PF System
PF Parameters Coil No. 14 Iop 14.5 kA Bmax 4.5
T dB/dt lt 7 T/s Top lt4.2K Cond. CICC Material Nb
Ti
PF9
PF11
PF7
PF13
PF5
PF3
PF1
R1.94, a0.44, kx1.76, dx0.56
R1.94, a0.46, kx1.69, dlx0.54

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TF System
Manifold Interface
TF Parameters Coil No. 16 Bmax 5.85 T
(6.72T) Iop 14.3 kA (16kA) Estored 298 MJ
(390MJ) Top lt4.2K (3.8K) Cond. CICC Material NbTi
Shearing Pins and Bolts
TF Wedges
The maximum central force is 1293 ton
The maximum out-plane torque is 332 Tonm
The maximum tress on TF is 340 MPa

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16 completely welded sections of double-shell
structure
Vacuum Vessel
Vacuum Vessel Parameters Weight
43 ton IV-Surface( with ports) 162
m2 IV-Volume(without ports) 40 m3 Port
No. 48 Material 316L Toroidal
Resistance 85.4 µ?
48 ports for pumping, heating driving and
diagnostics
The maximum tress on VV is 170 MPa

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ASIPP
Cryostat Vessel
Cryostat Vessel Parameters Inner Diameter
7322 mm Outer Diameter 7372 mm Height 7545
mm Port No. 72 Material 304L
The maximum stress with 1.5atm pressure inside CV
is 27MPa
The maximum tress on CV is 144 MPa

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In-vessel Components
Divertor
Supports
Feed back control coil
Passive stabilizer
Cryopump
Cooling bake circuit

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Superconducting Technology Development Main
Parameters of SC Strands Strand Diameter
0.85 mm Critical Current 500 A (at 4.5
K, 5 T) 426 A
(at 4.5 K, 5.8 T) Number of Filament
8910 Filament Diameter 6 µm Twist Pitch
10 mm CuSC 1.381 RRR
gt 70

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Short Samples Parameters

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B5.8 T dm/dt2.8 g/s
Ic are 10-12 lower than strand data. The
degradation could be due to the filaments broken
in the strand.
Lower Tcs than calculations could be caused by
high inter-strands transverse resistance and
stainless steel wrapping on the sub-cable.
Time constant are much lower than expected.
Wrapping function at high frequency was confirmed
by lower losses.

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The main parameters of the EAST CICC
TF CS/Divertor Big PF
Rated peak field 5.8 T 4.5 T 2 T
Rated operation current (Iop) 14.3 kA 14.5 kA 14.5 kA
Rated operation temperature 4.2 K 4.2 K 4.2 K
Cable configuration (2SC2Cu)?3?4?51CCC (2SC2Cu)?3?4?51CCC (1SC2Cu)?3?4?51CCC
Conductor dimension 20.4? 20.4 mm2 20.3? 20.3 mm2 18.5? 18.5 mm2
Conduit thickness 1.5 mm 1.5 mm 1.5 mm
Number of SC strand 120 120 60
Number of Cu strand 12021 12021 12021
Diameter of SC strands 0.850.87 mm 0.850.87 mm 0.850.87 mm
Diameter of copper strands 0.98 mm 0.98 mm 0.98/0.87 mm
RRR of Cu strands gt 100 gt 100 gt 100
Coating materials Pb-30Sn-2Sb Nickel Pb-30Sn-2Sb
Solder thickness on strands 2-3 ?m 2 ?m 3 ?m
Cu fraction (fcu) 0.54 0.54 0.44
Helium fraction (fhe) 0.34 0.35 0.359
Iop/ Ic 0.28 0.224 0.31
Temperature margin (Tcs-Top) 1.88 K 2.54 K 2.29 K
Energy margin (?E) 250 mJ/cm3 350 mJ/cm3 400 mJ/cm3

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A 600 m CICC jacketing line was set up in ASIPP
and more than 34 km CICC have been produced.
Conduit Cleaning
Conduit Surface Check
Conduit Welding
Conductor Extruding
Conductor Receiving

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Technologies to fabricate PF and TF coils in
pre-bending and continuous winding way have been
developed.
15 PF coils fabricated

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To test the superconducting performances of coils
before installation, a cryogenic test facility
system set up in ASIPP.
Power Supply 24 kA/0-100V(CW) 100kA/0800V(
5s)
Cryogenic test facility system
Cryostat with CLs Diameter 3.4 m Height
6.7 m Vacuum 1 10-5
? Current leads 2 pairs
20-30 kA
Control and Data Collection System
Refrigerator 500 W/4.5 k

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The tests of the CS prototype coil had shown
pretty good results in 2003.
CS prototype coil inside the cryostat of the test
facility
Current charge/discharge
0.5 kA/s
Iq16.37 kA Top6.79K Bmax3.6T
1kA/s
Quench current test Extrapolated Iq 54kA (3.8K,
4.5T)
AC losses test

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ASIPP
After TF prototype coil test, sixteen TF magnets
have been tested successfully and shown similar
performances
One TF coil inside the cryostat of the test
facility
Quench current test Extrapolated Iq 58kA (3.8K,
6.72T)
1 TF
6 TF
5 TF
4 TF
3 TF
2 TF
12 TF
13 TF
14 TF
15 TF
16 TF
8 TF
9 TF
10 TF
7 TF
11 TF

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ASIPP
The central solenoid (CS) assembly, which is
consisted of six coils, has been tested before
installation.
CS in the assembly
CS installation for test

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ASIPP
HTc Current Leads

• To reduce the cryogenic consuming, EAST uses 5
  pairs HTc current leads at the first operation
  stage.
• 13 pairs of HTc current leads have been tested
  with LN and at the same operation condition from
  15kA to 20kA.

Coolant inlet/outlet

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Installation of the HTc Current Leads
LN2 vessel
HTc modules
Insulation breaks
CICC joint terminals

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• Cryogenic and Refrigerator System
• The SC magnet system has a cold mass of 200 tons
  at 3.8-4.5K and 20 tons at 80K.
• For normal operation the machine heat load
  estimated is about 890W/4K and 17kW/80K.
• One pair of 14kA conventional current leads for
  the TF coils and 6 pairs of 15kA leads for the PF
  coils require 7.5g/s cooling flow.
• An oil ring pump has been employed to reduce the
  helium suction pressure to 0.37 bars at the
  volumetric flow rate of 3100 Nm3/h for ensuring
  1050 W/3.5 K refrigeration ability.

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ASIPP
Schematic Flow of Helium Refrigerator 1050W/3.5K
200W/4.5K 13 g/s LHe (1325)kW/80K

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• Power Supply System
• The power supply system consists of
• Power supplies for Toroidal Field (TFPS),
  Poloidal Field (PFPS), Fast Plasma Position
  Control (FPPS), Auxiliary Heating and Current
  Drive (AH/CDPS)
• A new 110kV overhead line and a 110kV/83MVA
  substation was set up at ASIPP.

110kV/83MVA Power Substation

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36 group 15 kA AC-DC convertors total nominal
power 210 MVA
The Power Distribution System
Dump resistance and explosive breakers

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• The LHCD System Consists of
• 20 klystron amplifiers with CW output power of 2
  MW in total at a frequency of 2.45 GHz.
• 1.5 MW/2.45 GHz, instead of 2 klystron amplifiers
  with 1.5 MW output power and 1000s pulse length
  at a frequency of 3.7 GHz.
• Antennas consisting of 4 32 sub-wave guides.
• A 4 MW/4.6 GHz system is planed to be set up in
  the future.
• The ICRF System is Composed by
• Two subsystems, each one has 1.5 MW output power
  and the frequency range is from 30MHz to 110MHz.

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ASIPP

• Control System
• The EAST control system features PC (personal
  computer) constructed Distributed Control System
  (DCS), including plasma control system (PCS), and
  other sub-systems.
• The EAST PCS is based on and developed from
  DIII-D PCS and strongly supported by DIII-D PCS
  team.
• Aimed at Real-time Shaped Plasma Control
  (RT-EFIT).

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ASIPP
DIII-D/EAST PCS is Flexible, Scalable Multi-cpu
Control System Supporting Arbitrarily Complex
Algorithms
DIIID/EAST plasma control system hardware
structure

• Commercial Off-The-Shelf components

DIIID/EAST Tokamak
IDL-based GUI
Linux-based OS and C-code allows complex
algorithms, rapid modification and development
32 96 channel PCI format 250 kHz D-TACQ
digitizers
Intel VME cpu/digital and analog output converters
2.4 GB/sec Myrinet network
Multiple CPUs run in parallel 10 ?s -10 ms cycle
times
PCS real-time Network Gatewaycomputer and user
interface host
Remotely located real-time computers
3.1 GHz Real-time Intel computer array

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ASIPP

• Diagnostics
• Limited diagnostics are employed, such as plasma
  current, position and shape, electron density and
  temperature, radiation power, impurity content,
  MHD and fluctuation, edge plasma, divertor and
  plasma facing components.
• Only magnetic measurements, part of laser
  interferometers, plasma image and RGA will be
  newly built, while others will be modified from
  the HT-7 diagnostics equipment.

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ASIPP
The assembly procedure of the EAST machine
consists of three main sub-procedures
The second procedure
The bases assembly procedure
The tori of VV, vacuum vessel TS and TF assembly
procedure
The peripheral assembly procedure

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ASIPP

• The bases assembly procedure
• The three tori assembly procedure
• The peripheral parts assembly procedure

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View Inside the vacuum vessel of the EAST

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3. Results of the First Commissioning

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ASIPP

• The main purposes of the first commissioning
• Validation of correctness, reliability and
  security of the tokamak machine integrated with
  sub-systems, such as the cryogenic and
  refrigerator system, vacuum pumping system, the
  power supply system, feeders with current leads
  and superconducting bus-lines, etc.
• Debugging and adjusting of the quench detection
  system, the interlock and safety system, the
  machine diagnostic system, PCS checking of the
  insulation, the magnetic field shapes and
  distribution, mass flow, pressure drop, CICC
  joint resistance, displacement of the magnet
  during cooling down and charging.
• Providing necessary experiment data and suggested
  operation modes for the future operation.

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• Important achievements
• The cryogenic ability of the system is above the
  design value and reached to 2.4kW/4.5K.
• Four sets of PF power supply system and the TF
  power supply system energized different coils
  successfully.
• The pumping system successfully operated through
  whole commissioning experiments.
• The superconducting magnet system worked very
  well.
• Quench detection and magnetic diagnostics were
  tested successfully.
• Eight pairs of copper current leads and four HTc
  current leads worked properly.
• Most of total eighty-seven CICC joint resistances
  are less than 10 n?. But few of them are more
  than 15 n? and but still acceptable.

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ASIPP

• Problems we suffered
• Shafts of four turbines of the cryogenic system
  got stuck several times. Finally, one of them
  totally damaged.
• After pumping and cooling down, the insulation
  resistance of the magnet system dropped down to
  less than 0.5M? (2.75kV) from 2G? (5.7kV) before
  the cryostat vessel was covered, which was caused
  by the dirtying surface on the current leads,
  quench detecting wire and its sockets.
• One minor leakage was found during cooling down
  in the outer thermal shield system.

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4. Future Plan

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Three phases of operation

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CICC Technology
SC magnets Technology
Insulation Technology
Machining
ITER related technologies developed in ASIPP
Power Supply System Technology
SC magnet test
Cryogenic Technology
Plasma Facing Components
HTc Current Leads
PCS

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ASIPP
EAST vs. ITER

• ITER
• Experimental reactor
• R6.2 m, a2 m
• Pulse length 400 s
• Single null plasma
• Superconducting magnets, steady-state heating and
  diagnostics, remote control, shield and six
  tritium blankets

• EAST
• Experimental device
• R1.9 m, a 0.5 m
• Pulse length 1000 s CW
• Single/Double null plasma
• Superconducting magnets, steady-state heating and
  diagnostics, one or two tritium blankets
• Experimental benchmark for ITER

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ASIPP
5. Summary

• All the main technologies mentioned above have
  been developed very well in ASIPP in the past
  five years.
• The successful EAST first engineering
  commissioning gives the EAST team strong
  confidence that the EAST will be successfully
  constructed.
• Now all the ports and main in-vessel components
  have been installed, except for the graphite
  armors.
• The first physical experiment is going on right
  now. But the turbine problem happened again.
• EAST system will provide fusion community a very
  good international research facility for steady
  state divertor plasma research.

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ASIPP
Thanks for your attention!

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