Korea Superconducting Tokamak Advanced Research Sample image2 Sample image3 Installation of 84-GHz, 500-kW KSTAR ECH system 정진현, 박승일, 조무현, 남궁원포항공과대학교 배영순, 한원순, 안상진국가핵융합연구소 2007 년도한국물리학회추계학술논문발표회 October 19, 2007 제주국제컨벤션센터, 제주시 2007 2nd Korea-Japan workshop on heating technology of Fusion plasmas, August 16-17,Hotel Ramada, Jeju, Korea 1/ 16
Timing and Triggering GPS Triggers for charging & switching (from KSTAR Central Control System) Triggers for charging & switching (from KSTAR Central Control System) PF coil current T HVON (-10 s) +24 kv -56 kv Trg. 1 Trg. 2 HV ON T ECH (-150 ms) APS 80 kv CPS ECH Pulse ON 0 ECH RF Pulse HV OFF (Auto. Off By Local driver) Plasma current T HVOFF (+10 s) Body charging voltage time Cathode charging voltage time PXI Ethernet PLC Optical HV cable Send Voltage & Pulse length Value Trg. 1 Trg. 2 A P S C P S Timing board (EPICS server) HV On/ Off E/O Gate driver SW On Optical time delay by local server (PLC) CPS & APS HV charging time = 2 ~ 3 s Pulse rise time = 10 microseconds 2007 KSTAR Conference, August 24-25, 레이크힐스호텔, 속리산 2/20
Layout of ECH Systems 63.5-mm circular corrugated waveguide Power Supply 3. ECH Launcher -84 GHz, 500 kw, 2 s - Front-steering launcher with two mirrors 2. ECH Transmission Line System - 31.75-mm circular corrugated waveguide (total length: ~ 40 m) - Diamond window - DC break - Bellows -RF gatevalve - W/G switch - Dummy load - Miterbends (regular, power monitoring, arc detector, polarizer) Control system 1. ECH Power System -84 GHz, 500 kw Gyrotron -1.5 MW Power Supply system -Control System 3/20
Ion pump Collector (GND) Body (+24 kv) Cathode (-56 kv) 84-GHz, 500-kW Gyrotron Ion pump Diamond window 80 inches (~ 2 meters) Specifications of Gyrotron (CPI VGB8084) Frequency: 84 GHz with 0.1 GHz bandwidth Power: 500 kw with duration of 2 sec pulse Gun Type: Diode-gun with cathode of 40.6 mmradius Cavity mode: TE 15,4,1 (31-kG focusing field) α = 1.4 (80 kv and 25 A) Collector Potential Depression Cathode-Collector Voltage: -56 kv Cathode-Body Voltage: -80 kv Beam Current: 25 A Heater voltage: 28 V, Heater current: 6 A Efficiency: 41 % RF output mode: TEM 00 Gaussian mode with linear polarization Diamond window: edge-cooled single-disk with 2.0- inch (50.8 mm) aperture and 0.059-inch (1.5 mm) thickness 4/20
Initial Short Pulse Test (20 microseconds) Collector Beam voltage (80 kv) Ch3: I BODY Power monitoring Miter Bend Reverse (80 db) Body Beam current (23 A) 500 kw 84 GHz RF Forward (80 db) Cathode Body current Level Set Attenuator Horn antenna WR10 waveguide RF detector RF power: ~ 500 kw Ch2: I BEAM Detector Ch4: V RF Ch1: V BEAM 5/20
Initial Short Pulse Test (20 microseconds) IR image measured at the end of output arm of the power monitor miter bend Ellipsoidal focusing mirror IR camera Focused beam before the input of 31.75-mm ID corrugated waveguide Beam radius is 16 % of waveguide diameter (w o < 0.322D) Normalized intensity 1.0 0.8 0.6 0.4 0.2 0.0-8 -6-4 -2 0 2 4 6 8 Measured data Gaussian fit of data Position (cm) 1/e 2 radius w 0 = 1.35 cm At the end of output arm of the power monitor miter bend 6/20
Frequency Measurement WR-10 Waveguide Harmonic mixer Spectrum analyzer Sapphire window for RF sampling attenuator L-Box 3dB Magic Tee Frequency meter WR-10 W/G Oscilloscope Harmonic mixer Spectrum analyzer Frequency meter (W-band) 7/20
Installation of ECH T/L system - ECH room - H G Opening hole W17-2 F A A B C D E F G H 84 GHz gyrotron L-box Power monitoring M/B Waveguide switch 1 st Al tank load Polarizer M/B Polarizer M/B Waveguide switch C D B 8/20 8/25
Opening hole W17-1 Installation of ECH T/L system - Tokamak room - K N-m port K L M N O P Q R S T U Arc detector M/B Power monitoring M/B Pumpout tee Waveguide switch Waveguide dummy load 2 nd Al tank load Diamond window Pumpout tee RF gate valve Bellows DC break V 84 GHz ECH launcher N Q R S T U V L O M P 9/20 9/25
Vacuum pressure [torr] 10 4 10 3 10 2 10 1 10 0 10-1 10-2 10-3 10-4 10-5 10-6 10-7 ECH launcher 0 24 48 72 96 DC break Schematic of ECH T/L Vacuum System Bellows Time [hour] RF gate valve Pumpout tee #1 L-box #2 1st dummy load #3 W/G middle #4 Pumpout tee 1 #5 2nd dummy load #6 Pumpout tee 2 (KSTAR) #6 KSTAR vacuum Operation pressure Diamond window #5 2 nd Al tank load Vacuum gate valve Waveguide dummy load Waveguide switch #3 ECH vacuum Pumpout tee Vacuum gate valve TMP #2 ECH room Vacuum gate valve Arc detector Miter bend #4 #2 Tokamak room 1 st Al tank load Polarizer Miter bend Waveguide switch #2 #3 Power monitoring Miter bend Dry pump Power monitoring Miter bend Polarizer Miter bend Waveguide end Regular Miter bend with vacuum port Waveguide switch #1 84 GHz, 500 kw Gyrotron #1 TMP #1 L-box Vacuum gate valve corrugated waveguide 31.75 mm (I.D.) Dry pump 10/20 10/25
Measurement of Transmission Efficiency I. Measurement of transition loss II. Measurement of transmission line loss Spectrum Analyzer 84 GHz, 50 mw Gunn Oscillator KSTAR ECH Transmission line system 31.75 mm Corrugated W/G W-band Harmonic mixer & Crystal detector WR10-31.75 mm Transition WR10-31.75 mm Transition Direct Reading Attenuator Transmission line components waveguide ohmic miter bend Ohmic loss by E-plane phased correct mode conversion loss [db] 0.04764 db/km 0.0005665 0.0452719 loss [%] Qty. 1.103 % / km 0.03 0.013 1.048 7 7 loss [%] 0.033 0.091 7.335 mode conversion loss waveguide switch pumpout tee (gap = 10 mm) RF gate valve (gap = 1 mm) DC breaks (gap = 4 mm) total power loss (without mode conversion loss) Measurement of ECH T/L Transmission efficiency diameter change axial offset Tilts 0.0000043 0.0000003 0.0003500 0.000099 0.000006 0.130 % / 2mrad 0.200 0.100 0.100 0.008 0 0 30 2 2 1 1 0.000 0.000 3.900 0.400 0.200 0.100 0.008 12.07 87.00 11/20
Direction Poloidal Φ From vertical Installation of ECH Launcher Direction Toroidal θ From launcher to tokamak Upper limit -55 deg. CCW limit -38 deg. Lower limit -90 deg. CW limit 38 deg. Accuracy of ± 1 deg. at a rate of 10 deg./s g θ X Y Φ z Z N-m port Microwave 47 mm 154.7 mm 1068.4 mm Pivot point (279, -252.2, -2800) Installation for ECH launcher 12/20
Inverter (800 Hz) Schematic of 84 GHz Gyrotron Power Supply 0.2 H 20 Ω 20 Ω IGBT SW floating i C Arc fault (> 30 A) 500 mh/25 A 5 kω/200w 100 kv ISO TR Heater Power Supply 28 V, 6 A 1.5 kv/40 kv Inverter (800 Hz) 5 μf 1.5 kv/40 kv Inverter (800 Hz) 1.5 kv/40 kv Inv. Crowbar Switch 100 kv ISO TR Body current Metering shunt (100 Ohm) Acceleration Power Supply IGBT SW 3.8 MΩ Modulation Switch 30 kv Clamp MOV 90 kv K B C Clamp Diode 40 kv PIV RF beam collector current metering shunt (0.2 Ohm) VCB 1.5 kv 1200 A FAST INTERLOCK MATRIX PLC 3φ 1.1 kv 13/20
Test of 84 GHz Gyrotron Power Supply Power Supply 60 kv, 25 A, 2 s HVS Tank Gyrotron APS Tank Filter Deck Heater ISO TR APS Rectifier Tank VCB Inverter 14/20
Local I&C Configuration KSTAR Control EPICS server (PCI-6220) RS422 Local HMI TOP6 P L C - Op. mode selection & - Parameter selection. (voltages, pulse width, modulation parameters) - HV ON, RF ON RS232-optic HV ON/OFF state value, Pulse width value, Op. mode state value, HV ON KSTAR triggers SW KSTAR EMG STOP Local triggers Matrix board: IGBT gate drive & Fast Fast interlock board LOCAL Oscilloscope & DAQ System Run waveforms Ethernet Hardwire Slow interlock & System ready & KSTAR interlock (I/O) Optic-RS232 H P S System ready & fault check, Send voltage values C P S A P S Optic Optic Fast fault processor (FFP) NI PXI (SCXI-1303) HV ON/OFF GATE DRIVING Fast interlock signals (T o, LHe level, T sheid, etc) 15/20
Local Control System PXI & PLC controller Fast fault signal processor HMI PXI Fast Fault Processor PLC Matrix Board Vac. pump controller Cooling water flow & temp transmitters Instrument controllers (vac. guages, ion pump, collector coil, polarizer MB 16/20
Test Waveforms for Gyrotron Power Supply - I Ch4: (CPS current) RG58 Ch1 : V CPS CPS HVS APS Body current Metering shunt (100 Ω) HV floating Ch2 : V BODY HVS Dummy resistor 2.44 kω Ch3: Collector current metering shunt (0.2 Ω) Pulse length: 2 sec Ch1: CPS voltage (20 kv/div) Ch2: Body voltage (20 kv/div) Ch3: CPS current (25 A/div) Ch4: CPS current (25 A/div) Math (CPS-Body = APS voltage): 50 kv/div Parameters of CPS (test with dummy resistor) Output Rise-time of output volt. Fall-time of current Value -80 kv, 25 A, 2sec. Remarks -60 kv, 25 A with CPD Achieved within 15 us Achieved within 25 us 17/20
Crowbar System IGNITRON Δt = 8 usec V CAPACITOR Crowbar ON Fast interlock (Signal from arc detector) Ch1:V CAPACITOR Parameters of IGNITRON IGNITOR Ratings Length of firing pulse Peak anode voltage Anode current Fault energy to Gyrotron Specification 1500 (min.) ~ 3000 V (max.) 100 (min.) ~ 250 A (max.) 10 usec 50,000 V 25,000 A < 6 Joule Remarks NATIONAL ELECTRONICS NL-37248 series connection with 2 set Achieved within 2.5 Joule 18/20
Current Status of 84 GHz Gyrotron System -The 84 GHz Gyrotron system is moved at CPI for repair the vacuum leak - As the failure analysis, vacuum leak occurs in braze joint of collector interior Collector interior with blue tape next to leak site in braze joint Installation of the VGB-8084 Gyrotron into the vacuum bell of the bakeout station to remove water from tube cooling circuits. 19/20
Summary The KSTAR ECH system is installed and the short pulse test of Gyrotron is carried out using the 20 usec PFN (Pulse Forming Network) modulator system. The overall test of 1.5 MVA (60 kv, 25 A) power supply system using dummy resistors has been carried out to confirm the reliability and the protection of the gyrotron. With dummy resistors, the CPS (Collector Power Supply) is operated at 60 kv, 25A, and 2 s, and the APS (Accelerating Power Supply) provides a stable acceleration voltage of 80 kv with respect to the cathode. It is confirmed that the fast interlock unit turns off the high-voltage switch and turns on the crowbar switch within 10 us under any fault condition. The 84 GHz Gyrotron occurs vacuum leak and it is under repair. About six month later, operation will be start again. 20/20