HT-7U CASIPP 1 The Engineering Design of the Poloidal Field System of HT-7U Tokamak PF Group of...

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The Engineering Design of the Poloidal Field System of HT-7U Tokamak

PF Group of HT-7U TeamChinese Academy of Sciences, Institute of

Plasma Physics (CASIPP)

P.O.Box 1126, Hefei, Anhui 230031 P.R.C.

HT-7UHT-7U

Wu Weiyue, Li Baozeng, Cao Yunluo

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1. Main parameters of HT-7U

2. PF coils position & size

3. Conductor design

4. Winding & insulation

5. Analysis on strength of the magnets & structure

6. Fabrication & testing

7. Outlook for the near future

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1. Main Parameters of HT-7UMajor Radius, Ro 1.79 ~ 1.96 m

Minor Radius, a 0.4 ~ 0.55 m

Plasma Current, IP 1 MA

Elongation, Kx 1.6 ~ 2

Triangularity, x 0.6

Toroidal Field, Bt 3.5 T

Plasma Duration ~ 1000 s

Configuration:Pump limiterDouble nullSingle null

Heating and Driving:LHCD 3.5 MWICRH 3~3.5 MWECRH 0.5 MW

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7095mm

3430mm

7600mm

2500mm

H13300mm

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PF1

PF3

PF5

PF7PF9

PF11

PF13

550711

501487

11991339

28903019 3235

3324

1710

1809

2 08 5

1 48 8

1 70 3 9 9

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4 54

8 20

1 01

Plasma

952

126

126

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2. PF Coils Position and Size

Center of the device

Equator plane

All PF coils are placed symmetrically about the equator plane

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6.65m

6.47m

PF Magnets System of HT-7U

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Parameters of PF coils No. R(cm) Z(cm) Nr Nz Bw(cm) Bh(cm)

1 56.404 4.1085 7 20 2.154 2.213

2 56.404 54.3725 7 20 2.154 2.213

3 56.404 104.6365 7 20 2.154 2.213

4 96.447 172.05 11 4 2.154 2.213

5 96.447 181.921 17 12 2.154 2.213

6 289.623 149.92 6 10 1.974 2.034

7 324.019 83.3 4 8 1.974 2.034

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3. Conductor for PF coils NbTi strands(UNK) with segregated copper is chosen for all PF coils

The configuration of the PF CICC Ⅰ(for PF1-5)

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The configuration of the PF CICC Ⅱ (for PF6-7)

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PF1-PF4 PF5-PF6Strands conf. (2SC+2Cu)34(5+1) (1SC+2Cu)34(5+1)

No. of Sc strand 120 60

No. of Cu strand 141(Φ0.98) 120(Φ0.98)+21(Φ0.87)

Surface Coating with Ni 2m Pb-Sn-Sb3m

Peak field 4.5T >2.5T

CICC size 20.4mm×20.4mm 18.6mm×18.6mm

Conduit material 316LN 316LN

Conduit thickness 1.5mm 1.5mm

Current (Io) 14.5kA 14.5kA

f(Io/Ic) 0.224 0.31

Temperature Margin(ΔTs) 2.24K 1.99K

Stable margin(ΔE) 350mJ/cm3 400mJ/cm3

Parameters about PF CICC

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4. Winding and insulation

Turns insulation 2 layers kapton 0.06mm, fiberglass 0.44mm;

Pancake insulation 0.84mm fiberglass carpet;

Ground insulation 5mm fiberglass wrapping;

Vacuum pressure impregnates with epoxy resin

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PF coil’s winding structure

Turns 140 (1 CICC)

Inner Radius 55cm

Outer Radius 71cm

Height 46cm

CICC Length 565m (no joint)

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7 20=140 turns

2 current terminates

4 cooling tubes

Cooling channel L is 130m (28 turns)

View of one piece central solenoid coil

0.45m

0.16m

1.1m

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6 coils through bolts preloading;

Height is 4 m;

Total is 6140=840 turns

4m

5. Analysis on magnets strength and structure

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Helium tubes

Current terminates

Top view of central solenoid

1.87m

Helium tubes in a different angle with the current terminates about 45 degree;

6 coils are set in different angle each other also, according to the terminates and helium tubes.

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I (KA)

t (s)

PF coils current waveforms for the basic scenariosPlasma current

Ip ignition

OH discharge

OH charge end

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Moment

Moment

Moment

Fr

Fz

Fr

Fz

Fr

Fz

Electromagnetic Force on solenoid are different on each coil and in each moment.

Analysis on the structure for the preloading force and Electromagnetic Force on support parts of the assembly solenoid.

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6.1mm & 279 MPa

0.3mm & 16 MPa

47.5 MPa

The results show the design on strength is suitable and safety enough.

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CSMC after winding

CSMC with supports

A central solenoid model coil (CSMC) had been fabricated in 2000 & tested in 2001.

6. Fabrication and testing for PF system

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Parameters of CSMC Inductance 15.4mh

Cooling channel 365m

Ioperating 14.5/18KA

Peak field 5T

Stored energy 1.62/2.5MJ

Parameters of solenoid

Turns 914=126

Inner radius 37.6cm

Outer radius 57.3cm

Height 28.6cm

CICC length 368m

Inductance 26mh

Cooling channel 130m

Ioperating 14.5KA

Peak field 4.5T

Stored energy 2.74MJ

Turns 720=140

Inner radius 55cm

Outer radius 71cm

Height 46cm

CICC length 565m

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CSMC set in testing facility in 2001

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Test Facility Parameters

Din 3.1 m

Hin 4.7 m

Vacuum1×10-5

torr

Current leads2 pairs

Imax. 30 kA

Refr.

500W/4.5k

Topr. 4.5/3.8K

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4 days cooling down for CSMC in 1st testing

Part view next

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Resistance disappeared in 2 days from 6.5m

Part view next

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Resistance from 1m to 80 in half hour

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13 KA in CSMC when 1st testing in 2001

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CSMC just VPI last month in CASIPP

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A 600m CICC jacketing line has been set up in CASIPP

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Several types CICC have been fabricatedMore than 8 types CICC with different configuration have been designed and made during past three years.

2 types CICC was made in China(including cabling)

6 types CICC cabling in VNIIKP(Russia) and jacketing in CASIPP

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Two pieces 600m CICC has been fabricated in CASIPP this year

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7. Outlook for PF system

• The final design of the PF system will be finished this year.

• One section of central solenoid coils will be fabricated and tested in the end of this year.

• All the components(coils, structure and connecting parts) of PF system will be fabricated completely in next year. The assembly central solenoid will be testing with the structure and preloading.

• The assembly of HT-7U device is planed to start in next year.

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HT-7U device will be build in Institute of Plasma Physics, Chinese Academy of Sciences(CASIPP)

Sciences Island

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Diameter ф0.87mm

Critical current (Ic) 500A(4.5K,5T)

426A(4.5K,5.8T)

Number of SC filaments 8910

Diameter of SC filament 6μm

twist 10mm

Ratio of s. cu 1.38:1

Parameters of NbTi Strands (UNK)

•Polyamide+Vacuum Pressure Impregnates

•No strands splice

•No lubricant

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• Change the insulation bmp with Zhu Ning new-drawing.