Post on 24-Mar-2020
THE PRESENT STATUS ANDPROGRESS OF EAST(HT-7U)
TOKAMAKEAST(HT-7U) Team Presented by Weng Peide
Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei, Anhui, 230031, P.R. China
October 2003
ASIPP
Mission of the EASTThe main mission of the project is to develop anadvanced full superconducting tokamak and explore thescience and technological bases for fusion reactor.
• Demonstrate of steady-state operation with highplasma performance.
• Investigate of advanced tokamak physics anddemonstration of stationary H-mode operation bystrong shaping, current profile control and auxiliary heating.
• Investigate of particle and heat fluxes handling on atime scale much longer than the wall equilibration time.
ASIPP
ASIPP
Major Radius Ro 1.75 m
Minor Radius a 0.4 m
Toroidal Field Bo 3.5 T
Plasma Current IP 1 MAElongation Kx 1.6 - 2
Triangularity d x 0.4-0.8Pulse length 1000 sHeating and Driving:( first phase)
ICRF 3 MW CW
LHCD 3.5 MW CW
ECRH 0.5 MW
Configuration:Single null divertorDouble-null divertorPump limiter
Conductor design and R&D Conductor development• NbTi cable in conduit conductor• Lowest cost: using existing strands• Using segregated copper to increase copper ratio (as
stabilizer)• Different surface coating to control AC losses• Lower operating temperature to increase margin
Several versions of the conductor have been developedand tested in ASIPP, ISSSP Kurchatov and Sultanfacility at CRPP.
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Sub-cable test at ASIPP
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CICC for EAST TF & PF magnets
Large proportion of segregatedcooper in conductor (68%)Different surface coating forTF and PF respectively
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Short Sample test
Four 15 kA TFand PF short sampleconductors with differentcoating on the strands andSS foil wrapping on thethird sub-cable have beenmade in ASIPP and testedin SULTAN facility atCRPP.The Ic, Tcs, AC lossesand stability againstmagnet field disturbanceof the samples have beenmeasured and compared
Results of AC loses measurement
Transient stability against Magnet field disturbance
0 2 4 6
0
2
4
6
8
10
12
14 PF3 PF3 PF2 PF2 TF TF PF1 PF1
f, HZ
ac lo
sses
, mJ/
cc
0.25 0.30 0.35 0.40 0.45 0.50 0.55 0.60 0.65 0.70
0
50
100
150
200
250
T*T/
s
Iop/Ic
TF 5.8T T=4.6K PF1 4.5T T=5.8K PF2 4.5T T=4.6K PF3 4.5T T=4.6K
5.0 5.2 5.4 5.6 5.8 6.0 6.2 6.4 6.6 6.8 7.0 7.2 7.4 7.6 7.80
5
10
15
20
25
30
35
40
45
50
55
60
65
B=4.5 Tdm/dt=2.8 g/s
TF PF1 PF2 PF3 calculated
Crit
ical
cur
rent
Ic (k
A)
Temperature T (K)
IC measurement
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0-20
0
20
40
60
80
100
120
140
160
TF: 4.5T,14.3kAPF1: 4.0T,14.5kAPF2: 4.5T,14.5kA
TF PF2 PF3
Inte
grat
ion
of (d
B/dt
)*(d
B/dt
)*dt
, T2/
S
Tcs-Top ( K)
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.00.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
PF1&PF2: Void=36.67%PF3: Void=38.44%TF: Void=37.32%
(1/Void)0.72(19.5/(4*MF/(Visc*U))0.843+0.0265)*MF2*L/(2Dh*Dens*AHe2)
4 bar, 4 K Helium
PF2#PF1# TF
PF3#
∆P (1
00m
) [
bar ]
Mass flow [ g/s ]
Pressure VS mass flow rate
Test results• The Critical currents of the four conductors are lower than
the strand data 10-12% and the current sharing temperaturesof PF1 and TF are lower than the calculated value 0.2 K.
• The AC losses of four conductors are much lower thanexpected and have a non-linear behavior. The inclusion ofsegregated pure copper strands in the conductor will decreasethe coupling loss and consequently increase the transverseresistance greatly.
• The solder coating results lower inter-strand resistance canensure adequate current sharing, however, it bring highcoupling loss too, we will use it for TF magnet.
• The Nickel coating has relative higher inter-strand resistanceand can reduce the coupling loss effectively shows hightransient stability against magnet field disturbance, we chooseit for CS magnet.
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TF & PF conductor parameters ASIPP
CICC jacketing line
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PF coil
PF coil
PF coil
CS coil
TF coil supportsTF coil
EAST magnets
TF Magnet Design• The TF Magnet System consists of a toroidal
array of 16 D shape coils, each coil is composedof two packs of winding which to be wounduninterruptedly.
• NbTi Cable in Conduit Conductor withsegregated copper is chosen for TF magnet.
• The inner leg of TF coil cases is designed to bewedge-shaped to form a vault withstanding themagnetic centripetal forces.
• Vacuum pressure impregnation will be adoptedto enhance the insulation and integrity aftersetting coil into case.
ASIPP
TF ParametersMaximal field at coil 5.8TTotal turns 16 × 130Coil size (D Shape) 3.52 × 2.51 mWinding type 6 pancakesConductor size 20.4 ×20.4 mmLength of each coil 2 × 593.5 mLength of cooling channel 201 mOperating current 14.3 kAOperating temperature 3.8 KTotal storage energy 298.5 MJ
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Stress analysis of TF magnet
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PF Magnet design
• The PF magnet system consists of three pair ofCentral Solenoid coils and four pair of Poloidalcoils. They are placed symmetrically about thedevice horizontal mid-plane.
• The flux swing of the PF magnet will be 10 VSand it could induce 1 MA plasma current andsustain it up to 10 seconds without auxiliarycurrent drive.
• NbTi Cable in Conduit Conductor withsegregated copper is chosen for PF magnet.
ASIPP
18.6×18.620.8×20.8Conductor mm
PF13-14PF 11-12PF 9-10PF 7- 8PF1- 6
10Total flux swing VS
3.8Operating temperature K
6.8 /0.7dB/dt max T/s
14.5I max kA
1.54.3B max T
326020444140Turn
179221289103476Height mm
64685779188918891085Inner diameter mm
66506054267024011418Out diameter mm
PF Parameters ASIPP
I (kA)
t (s)
Current of PF coils
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Ip
TF coil case machining
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TF prototype coil winding
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PF coil winding
Vacuum pressure impregnation
equipment (VPI)for TF and PF coils
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TF coil after VPI
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Superconducting magnet test facility
Diameter available 3.1 m
Height available 4.7 m
Vacuum 1 × 10-5 τ
Maximal current 30 kA
Refrigerator 500W/4.5 k
The prototype of CS coil,two TF magnet and PFmodel coil have beentested in the facility
ASIPP
CS model coil test
PF model coil test
0 100 200 300 400 5000
2
4
6
8
10
12
14
climb rate 300kA/sdrop rate 300kA/s
I
Cur
rent
(KA)
time(S)
0
5
10
15
20
25
30
35
40
mag
netic
fiel
d(kG
)
B1
CS prototype coil in the test facility
ASIPP
2003-05-08 2003-05-09 2003-05-11 2003-05-13
0
50
100
150
200
250
300
Tin Tout
tem
pera
ture
of S
C co
il(K)
date
CS Coil cooling down
CS prototype coil test Simulate Plasma initiation
• excite the coil with the rate of 1 kA/s up to 15.2 kAand keep the flat top for 20 seconds.
• discharge the coil with dump rate –20 kA/s for 160ms up to 12kA, discharge the current from 12 kAto 10.6 kA with dump rate –10 kA/s for 140ms,from 10.6 kA to 6.6 kA with dump rate -5 kA/s for0.8 seconds, and -1.5 kA/s to 0.after that ramp the current from 0 to –13.2 kAwith the ramp rate -1.5 kA/s, keep the flat top for10 seconds and dump the current up to 0 with rateof 3KA/s again.
-10 0 10 20 30 40 50 60 70 80
-15000
-10000
-5000
0
5000
10000
15000
20000
ramp rate 3kA/s
ramp rate 1.5kA/s
drop rate 5 kA/s,0.8S
drop rate 1.5 kA/s
drop rate 10 kA/s,0.14S
drop rate 20 kA/s, 0.16 S(4.4T/s,0.16 S,0.7 T)
ramp rate 1kA/s(0.22T/s)
I=13.2 kA
I=15.2 kA(B=3.34 T)
Cur
rent
(A)
Time (S)
Current dm/dt 2.2g/s per channelTin=4.7K
Coil discharge simulate plasma initiation
14:15:3614:15:4414:15:5214:16:0014:16:0814:16:1614:16:2414:16:3214:16:40
-15000
-10000
-5000
0
5000
10000
15000
20000
T4
T3
T2b
T5
T2b: inlet temperatureT3, T4, T5: outlet temperature
tem
pera
ture
(K)
currentcu
rren
t(A)
Time
0 10 20 30 40 50 60 70
4.5
4.6
4.7
4.8
4.9
5.0
5.1
5.2
5.3
5.4
5.5
5.6
5.7
Time (S)
Outlet temperature rise due to coil fast discharge∆T max <0.5 K
CS prototype coil testAC losses test and Iq test
• Rise the current to 7.5 kA (∆B=1.65 T) withramp rate 5kA/S dB/dt=1.1 T/S) and drop thecurrent with same rate to 0.3 kA repeat 13times, measure the temperature rise . The outlettemperature T3,T4 and T5 increased 0.52-0.56K.
• Rise the current to 14kA with 1kA/s up and risethe current with 0.5kA/s continuously, the coilquenched when the current reach 16.37 kA.
15:58:24 15:58:36 15:58:48 15:59:00 15:59:12 15:59:24 15:59:36 15:59:48-1000
0
1000
2000
3000
4000
5000
6000
7000
8000
currentCu
rren
t(A)
0 10 20 30 40 50 60 70 80 90 100
5.0
5.5
6.0
6.5
7.0
7.5
8.0
8.5
9.0
9.5
10.0
dI/dt=5 kA/sdB/dt(max)=1.1 T/sdelta T (max)=1.6T
T3
T4
T5
T2b
T2b: Inlet temperatureT3, T4, T5: outlet temperature
tem
pera
ture
(K)
AC losses test
10:3610:40
10:4410:48
10:5210:56
11:0011:04
11:0811:12
11:1611:20
11:2411:28
11:3211:36
11:4011:44
11:4811:52
11:5612:00
-2000
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
T3T4T5
T2b
Tem
pera
ture
(K)
currentC
urre
nt(A
)
Time
0 10 20 30 40 50 60 70 80
4
6
8
10
12
14
16
18
20
22
24
Quench current test
Iq=16.37 kATop=6.79KBmax=3.6T
1kA/s
0.5 kA/s
Measured Iq =16.37kA (at 6.79K,3.6T)Extrapolated Iq= 53.9kA (3.8 K,4.5T)accordingto above results
TF coil test
Two TF coils (after VPI) have been tested• The coil and coil case was cooled dawn successfully
thermal-hydraulic behavior of the TF coil wastested
• Resistance of in coil joints and coil terminal jointswas measured
• Coil exiting at operation relevant condition(B×I)was carried out.
• Coil quench current was measured.
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ASIPP
TF prototype coil in test facility
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TF prototype coil cool down
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TF coil exciting
17.62kA Bmax4T T2c=6.55K
I=15kA at Tout=7.12K
Iq=15.6kA B=3.9T T=6.9K
Extrapolated Iq from the test results =55-65kA at Bmax=5.8T,T=3.8K
Vacuum Vessel & in vessel components
• Full welded double wall structure.• Sixteen horizontal ports and thirty two vertical ports for
Diagnostic, auxiliary heating and current drive• Divertor and limit armed by graphite and CFC tiles• Passive stabilizers and fast feed back control coils.• The vessel and first wall can be back up to 200 o C and
350 o C respectively.• Active cooling for first wall components and vessel wall.• Flexible gravity supports are adopted to compensate
thermal expansion.
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Vacuum Vessel
In vessel components
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Prototype of Vacuum Vessel Sector manufacture
Stress measurement ofVacuum Vessel portsand support
Vacuum Vessel port Bellows
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1/16 prototype vacuumvessel
Accuracy inspection of 1/16 prototype VV on A NC milling machine
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CryostatCryostat consists of upperhead, middle cylindricalsection and flat bottom sectionThe main functions of thecryostat is to provide thevacuum insulationenvironment for the operationof the superconducting coils,all of magnets, vacuum vesseland thermal shield aresupported on the flat bottomsection. Except 48 penetrationsfor the vacuum vessel portsextention, there are 19penetrations on the cryostatfor cryo-feeder line, access tothe cryostat interior for repairor inspection.
ASIPP
VV and CS Thermal shield The thermal shields comprisethe vacuum vessel thermalshield which interposesbetween the VV and the magnetstructures , the cryostat thermalshield which surround the wallsof the cryostat and thetransition thermal shields thatenclose the port connectingducts . The main function ofthermal shield is to reduce thethermal radiation from vacuumvessel and cryostat to themagnets. All of thermal shield issandwich structure using two of3 mm thick steel panels on bothside and reinforced by 19×19square cooling pipe in between.The thermal shield will be cooled by60 K Helium.
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Thermal Shield fabrication
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1/8 of bottom Cryostatthermal shield
1/16 of prototype VVthermal shield
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Installation of device support structure
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Bottom cryostat installed on the support
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Pre-assembling
Cryogenic Systems
• The cooled mass is around 165 tons at 3.8-4.5K and 20 tonsat 80K. The heat load estimated is about 890W/4K +7.5g/sand 30kW/80K for normal operation.
• 110g/s-3.8K supercritical Helium flow for the PF coils cooling,260g/s-3.8K supercritical Helium flow will be used for TFwindings and coil cases cooling. 110g/s-60K Helium flow willbe used for thermal shield.
• The cryogenic system consists of 2kW/4.4K+11kW/80Krefrigerator, 260g/s-4bar He pump, 1000L-3.8K sub-coolerand 10000L-4.5K liquid He tank, gas storage system andcompressor station.
ASIPP
CASIPP HT-7U
LN2
O RP
C1 C2
T1
T2
T3
4 . 4K
T4
Cu
rr
en
tleads
3.5 K
Thermal shield
19.5 bar
N2
He
300.0 K293.0 K 293.0 K
45.9 K
34.4 K
20.6 K
7 bar
0.37 bar
1 2 . 4K8.7 K
1.04 bar
6.4 K
T1
T2
T3
4.4 K3.5 K
148.5 g/s
210 g/s48.24 g/s57.4 g/s
1050 W
100 g/s
110 g/s
13 g/s0.47 bar
5 . 5 4K
4.5 bar
200 W Entropy
Temperature
Refrigeration cycleflow sheet of the refrigerator
3.5 K
CASIPP HT-7U
16 TF coils& 1st part ofTF cases
2nd part ofTF cases &structure
CS coils &PF7~8 &PF 13~14
PF9~10 &PF 11~12
4.5 K
SHe pump
Cooling of magnets
From J-T valve To oil ring pump
cool
dow
n
cool
dow
n
P=4.5 bar
cool
dow
n
Compressor station &Helium gas storage system
ASIPP
Power Supply System•Thyristor converter has been designed for AC/DC conversion in TF Power supply and PF Power supply•Multi-stage forced commutation techniques and thyristor DC circuit switches are applied in PFPS to reduce the peakpower.• Thyristor and explosive actuated DC circuit breakers have been developed for quench protection.• High frequency H-bridge inverter for FPPF is undertaken.•The TF power supply and first set of PF power supply has been fabricated and tested. It is used for the coil test successfully.
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First set of test PF power supply system
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One set of PF power supply of HT-7U is used for coil test
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The converter output current:test result: 15kA,cross zero
smoothly
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The operation of switchnetwork unit
test result: current 15kA, voltage
2.4kV, switch times 3ms;
83 MW transformer substation for HT-7U
ASIPP
ICRF & LHCD SystemThe LHCD System• 2.45 GHz existing system, which is used for HT-7
tokamak now, consists of 20 klystron amplifiers with CWoutput power of 2 MW in total.
• 3.7 GHz system consists of 2 klystron amplifiers with 1.5MW output power and 1000s pulse length.
The ICRF System Two subsystems, each one has 1.5 MW output power and
the frequency range is from 30MHz to 110MHz. The first1.5MW RF generator has been prepared and in benchtest now.
ASIPP
1.5MW/30-110MHz RF generator
1MW 2.45GH LHCD launcher
2MW LHCD power supply
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Summary• The engineering design and entire preconcerted
R&D program has been carried out. • Cryostat, 1/16 of prototype of Vacuum Vessel and
Thermal Shield are fabricated and delivered toASIPP already. All of components will becomplated in the beginning of next year.
• The prototype CS coil and TF coil has been testedThe results shows that all of the magnets can bemeet the design requirement. The SC Magnetfabrication is going on smoothly.
• It is hopeful to finish machine assembly in 2005.
ASIPP