Chang Ho CHOI

9, Apr. 2009

Chang Ho CHOI

9, Apr. 2009

KSTAR Commissioning

To test the components and systems after their constru ction.

To demonstrate that they are in accordance with the design objective and meet the performance criteria.

To identify any defect preventing the device operati on and plasma experiments.

• Vacuum commissioning• Controlled cool-down • SC magnet commissioning • 1st plasma generation

Major Procedure of Commissioning

Objectives

KSTAR commissioning

• Vacuum pumping system operation• VV baking operation• Discharge cleaning• Gas fuelling system operation

• Vacuum pumping system operation• VV baking operation• Discharge cleaning• Gas fuelling system operation

• Base pressure of VV

• Target : 5 x 10 -7 mbar, achieved < 3 x 10 -8 mbar

• Base pressure of cryostat at room temperature

• Target : 1 x 10 -4 mbar, achieved < 1 x 10 -5 mbar

• VV baking : 100 0C

• DC glow discharge cleaning(H2, He)

• Fueling system operation & testing

Major Operation

Operation Results

Vacuum commissioning

• Gas : He• No. of Electrodes : 1• RF Power : 200 W• DC Bias Voltage : 400 V• DC Current : 4 A• Operation Pressure : 6.0 ×××× 10-3 mbar

Vacuum Vessel Pumping (‘08. 03)

Cryostat Pumping (‘08. 03)

• Operation & control of the helium refrigeration system & helium distribution system (9 kW @ 4.5 K).

• Controlled cool-down of cold systems: SC magnet, structures, busline, thermal shields, current leads.

• Superconducting phase transition

• Operation & control of the helium refrigeration system & helium distribution system (9 kW @ 4.5 K).

• Controlled cool-down of cold systems: SC magnet, structures, busline, thermal shields, current leads.

• Superconducting phase transition

Major Operation

Control & Monitoring

• Hydraulic parameters • Temperature, pressure & flow distribution

• Mechanical monitoring• Stress & displacement

• Superconductor monitoring• Coil resistance & SC phase transition

• Safety• Vacuum & helium pressure monitoring

Cool-down

ComponentsImpurity Requirements

(ppm)N2 H2O Total

TF Coil 2.0 2.4 4.4 < 10

TF,PF Bus-Line 3.9 2.2 6.1 < 10

PF Coil 7.1 0.8 7.9 < 10

Thermal shield 2.6 3.0 5.6 < 10

TF Structure 1.7 2.6 4.3 < 10

7

Cleaning

Cleaning• Pumping & filling : < -65• Flushing : < 10 ppm

HDS

Cryostat

TF lead box

PF lead box

He

H2O

PF coil helium flushing Cryostat RGA (No helium leak)

Flushing Pressure : 8 bar

Cool down (2008. 4. 28)

RT (2008. 4. 3)

Temperature Monitoring

KSTAR successfully cooled-down to 4.5K (’08.4.26)

During cool-down, the temperature distribution was controlled within 50 K.

Tem

pera

ture

(K)

Time (MM-DD-YY)

50 K

Controlled cool-down ( T < 50K)

PF coil structure

4.5K SHe circulation : TF Coil

Temperature vs Mass flowT

empe

ratu

re(K

) / m

ass

flow

rat

e(g/

s)

Time (MM-DD-YY)

Temperature TF coil 300 g/s @ 4.5 K, 6.5 bar

PF coil310 g/s @ 4.5K, 6.7 bar

Thermal shield 190 g/s, @43 K, 15.8 bar

SHe circulator : 600 g/s

circulator “ON”

Mass flowrate

TF coil volume : 1,300 liter, mass flow : 9,000 l iter/hrPF6 coil volume : 540 liter, mass flow : 1,200 liter/hr

TF(16 coils, Nb 3Sn) SC transition

Rcoil (300K) : 957 mΩRcoil (18K) : 4.4 mΩRRR ~ 217

PF1U&L(Nb 3Sn) coil SC transition

PF7 U&L(NbTi) coil SC transition

-50

-40

-30

-20

-10

0

10

20

-1,000 0 1,000

Bu

s LI

ne

Vo

lta

ge

(μ

V)

Transport Current (A)

Joint Resistance

Voltage drops were measured at each bus line, which consists of several numbers (3~6) of electrical joints

Joint resistances were estimated by linear fitting to the measured V-I curves. All of the KSTAR lap joint resistances satisfied th e design value of 2 n Ω

KSTARBus Line

Number ofLap Joints

Total R[nΩΩΩΩ]

Average(nΩΩΩΩ / Joint)

Range(nΩΩΩΩ / Joint)

TF 8 12 1.5 1.2 ~ 2.0

PF1 11 5.5 0.5 0.5 ~ 0.7

PF2 11 10 0.9 0.7 ~ 1.1

PF3 20 18 0.9 0.8 ~ 1.1

PF4 20 18 0.9 0.7 ~1.1

PF5 20 24 1.2 1.0 ~ 1.5

PF6 22 6.6 0.3 0.3 ~ 0.4

PF7 12 6.6 0.3 0.2 ~ 0.3

Example : PF4 bus lines’ V-I Curve

Strain & displacementdesign value : < 500 µε (<100 MPa)measured value : max. 350 µε (70 MPa)

Str

ain

Time (MM-DD-YY)

design value : 8.10 mm @ 293Kmeasured value : 8.59 mm @ 310K

Dis

plac

emen

t (m

m)

Time (MM-DD-YY)

PF coil structure

Gravity support

Cryostat vacuum pressure

Electric power : 3.6 MW

Helium : LHe 14000 liter

Thermal loads : idle mode

Cooling power

Components Cooling power (@4.5K) Design Power (@4.5K)

TF, PF. SC-bus 1.4 kW 1.4 kW

TF, PF circulator 1.8 kW 1.8 kW

Thermal shield 1.3 kW 1.5 kW

Current lead 0.5 kW (5.1 g/s) 1.0 kW (10.3 g/s)

Total 5.0 kW 5.7 kW

Cold box cooling power : 9 kW @4.5K

• Superconducting joint resistance measurement• Insulation test at cryogenic temperature • Magnet power supply control• TF coil charge & discharge : up to 15 kA (B0 = 1.5 T, Bm = 3.1 T)• PF coil charge & blip operation

• Superconducting joint resistance measurement• Insulation test at cryogenic temperature • Magnet power supply control• TF coil charge & discharge : up to 15 kA (B0 = 1.5 T, Bm = 3.1 T)• PF coil charge & blip operation

Major Operation

Control & Monitoring

• Coil current & voltage• Field on SC magnet, in vacuum vessel• Coil performance under the dc & pulse field variati on• Interlock & safe discharge (quench discharge)

SC Magnet Commissioning

TF Insulation test

• DC 3 kV, less than 20 uA (Resistance : > 150 MΩ )

PF Insulation test

• Max. 6 kV, less than 3 uA (Resistance : > 2000 MΩ )

Magnet Pre-test (5.2 ~ 5.4)

TF Low Current Test (‘08.5.7)

TF Low Current Test (’08.5.8)

TF Structure Temperature•5kA FD : ~ 1 K Up

TF Coil Temperature • 5kA FD : ~ 0.1 K Up

TF Structure Strain• 5 kA FD : ~ 4.5 u ε

TF Low Current Test (‘08.5.8)

5,000 A

10,000 A

15,000 A

1.0 T

2.0 T

TF Coil Current (A)

TF Field (T)

TFPS Voltage (V)

TF Coil Temperature (K)

15 kA 10 min

Slow Discharge

2.76 Tat coil

-36.4 VSlow Discharge

4.75 K4.72 K

Current : 15 kA, 10 min Voltage : 8 V (Ramp-up) & -36 V (slow discharge) Field : 2.7794 T (coil) & 1.457 (Vacuum vessel) Temperature : 4.72 ~ 4.75 K (TF coil outlet)

TF 15 kA Charging (‘08.5.10)

TF Coil Current (A)

TF Coil Temperature (K)

TFPS Voltage (V)

TF Field (T)

4.7 K

2.78 T (coil)

1.46 T (VV)

TF Steady State Operation (‘08.5.12)

TF Coil Current : 15 kA

Plasma Operation (‘08.6.)

Plasma Performances PF coil and Plasma currents

First Plasma