1 Institute of Applied Physics RAS, Nizhny Novgorod, Russia ......2 GYCOM Ltd, Nizhny Novgorod,...

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23rd IAEA Fusion Energy Conference. Daejeon, Republic of Korea, 11-16 October 2010

Development in Russia of Megawatt Power Gyrotrons for Fusion

A.G.Litvak1, G.G.Denisov1, V.E.Myasnikov2, E.M.Tai2, E.A.Azizov3, V.I.Ilin3

1 Institute of Applied Physics RAS, Nizhny Novgorod, Russia2 GYCOM Ltd, Nizhny Novgorod, Russia

3 Tokamak Physics Institute of RRC “Kurchatov Institute”, Moscow, Russia

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OutlineFTP/1-2Ra:� ITER gyrotron parameters and design�Test facilities� Long-pulse test of Russian 170 GHz/1MW gyrotrons� Development of 1.5 MW gyrotron. Design and short-pulse test� Multi-frequency gyrotrons� Summary/Russia

- ITR/2-5Rc G. Gantenbain (Europe)- ITR/2-5Rb K.Sakamoto (Japan)

� Summary

Development in Russia of Megawatt Power Gyrotrons for Fusion

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Parameter Specified AttainedFrequency 170 ± 0.5 GHz 169.9 GHzRF output power ≥ 1 MW 1.2 MW (0.1s)Output radiation Gaussian mode Gaussian mode

Efficiency (with depressed collector) ≥ 50% ~53%

Pulse duration 400/1000 500s (1MW)800s (0.8MW)

Beam voltage < 90 kV 72 kVDepression voltage < 35 kV 30 kVBeam current < 50 A 45 ARun mode (duty factor, modulation requirements, etc.) under discussionReliability (lost pulses, cycling and environment control) under discussionEndurance (run time, warranty life time, storage time) Not specified

Russian ITER Gyrotron parameters

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ITER Gyrotron Design

• Depressed-collector with longitudinal beam sweeping • Output windows:

- 88(106)-mm CVD diamond main window- 123-mm BN ceramics relief window

• Built-in quasi-optical converter with adjustable last mirror• DC break insulator with forced air cooling (V-9) and

liquid cooling (V-10)• Cavity designed for TE25.10.1 operation mode • Diode type electron gun designed for current up to 50A• All inner surfaces are fabricated from copper and have

adequate water cooling for CW operation• Magnet bore diameter - 160 mm• Several modifications of the ITER gyrotron were

fabricated and tested

V-9 V-10

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New evacuated HE11 transmission line with terminal load

New Water-Cooled Load

(2006)(2006)(2006)(2006)

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Gyrotrons on the test site in Kurchatov Institute

Gyrotron V-9GYCOM LHe cryomagnetAir cooling of DC insulator

Gyrotron V-10CRYOMAGNETICS LHe –free cryomagnet

Liquid cooling of DC insulatorWindow1.48 mm 1.85mm

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V-9 Ceramic temperature (heating up and cooling down)

0

20

40

60

80

100

120

140

160

180

200

0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500

Time, [s].

Temp

eratur

e, [C

].

600 kW_air blowing600 kW_air convection

Overheating and breakdown(at max temperature~200°C)of DC insulator with air cooling

Evident need for switching To liquid cooling system

V-9 => V-10

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Output power & efficiency vs beam current at Ub= 73kV (44+29)

200

300

400

500

600

700

800

900

1000

1100

1200

20 25 30 35 40 45 50 55

Beam current, А

Рgss

.b,kW

25

26

27

28

29

30

31

32

33

34

35

Effic

iency

, %

Output power & efficiency vs recuperation voltage at Ub=73kV and 71kV / Ib=45A

700

750

800

850

900

950

1000

1050

1100

1150

1200

24 29

Urec, kVР g

ss.b,

kW40

45

50

55

60

65

Total

Efici

ency

, %

Рgss.b, 73 kV Рgss.b, 71 kVEff, 73 kV Eff, 71 kV

Modified gyrotron V-10. 0.1 s-pulse test: Output power & efficiency vs. beam current and retarding voltage

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V-10: Monitored traces (0.8MW / 800sec)

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Power components Value, kW/% Pin/(%Pg) Method of measurement

Total power input 1890/100 oscilloscopeTotal generated power 1090/57.7 /(100) Σ

Output power at MOU outlet(load+preload+HE11 line)

970(920+20+30)/51.3 (89) calorimetry & estimation

CVD diamond window dissipation 1.3/0.1 calorimetryCavity+mirrors+launcher dissipation 46/4.2 calorimetryTotal stray radiation 73/6.7 Σ

Absorbed in the MOU 32/2.9 calorimetryAbsorbed in the relief load + BN window 37/3.4 calorimetryRadiated through DC break+insulator 4/0.4 calorimetry

Collector power dissipation 800/42.3 calorimetry

V-10: Power balance

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Beam voltagekV

Beam currentA

RetardingvoltagekV

Output power*kW

Total efficiency(CPD)%

Attained pulse length / limitation

sec

71.5 27 30.5 600 ~54 800/Set

72 35 30.5 800 ~55 800/Set

72 45 30 1000 ~53 570/Conditioning

V-10: Summary of current experimental results

* paraxial part of output radiation

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Tasks for 2010

• Demonstrate 1 MW/1000 sec operation• Study power modulation• Reliability tests

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1.5-2 MW Gyrotron PrototypeDESING PARAMETERS

Parameter ValueFrequency 170 GHzNominal RF Power 1.5-2.0 MWRF Output Efficiency 50 %Accelerating Voltage 90-100 kVDepressed Collector Voltage 35-40 kVBeam Current 50 - 60 ACavity type CylindricalCavity magnetic field ≈ 7 TPulse duration 1000 sDepressed Collector Yes, single stageWindow Diamond (CVD)Output radiation TEM 00 Gaussian

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1.5-2 MW / 100 µs and 100-ms gyrotron prototypes

Collector

BN Window

Collector Depression Ceramic

Diode Electron Gun

Collector Coils

TE28.12Cavity

7T-Cryomagnet 160 mm-bore

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100-µs/5-10Hz gyrotron prototype. Test results.

OLD & NEW QO CONV.

η

P

10 20 30 40 50 60Beam Current Ib (A)

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0Efficiency η

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

2.2

Outpu

t Pow

er P

(MW)

TE28.12Up 170GHzU0=100kV R0=8.300mm NEWU0= 95kV R0=8.300mm NEWU0=100kV R0=8.127mm (Old)U0= 95kV R0=8.127mm (Old)

1.5 MW CW compatible

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100-ms gyrotron prototypeTest results 100µs/5-10Hz –– RF OUTPUT BEAM PARAMETERS

Thermo-images on the paper at different cross section (5mm/div)

L=0mm L=300mm

TE28.12UP 100kV/50A Diffraction lossesL=0mm P=1522 кВт (100%)L=300mm - 1.4% (98.6%)L=600mm - 1.7% (98.3%)

L=600mm L=1000mm

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� Tests of the ITER gyrotrons continue after debugging of the test facility in Kurchatov Institute (evacuated transmission line and modified power supply)

� New ITER gyrotron (V-10) with upgraded body insulation, liquid cooling system for DC-break ceramic, improved design of relief window is under tests now. Max total efficiency near 55% at 1MW level was attained. Maximal pulse duration of 800s at 0.8 MW power was limited at that time by the test stand. At 1MW power level the gyrotron V-10 up to now reached pulse duration of 570 s.

� Advanced short-pulse (100 ms) gyrotron model operating with TE28.12 mode demonstrated a robust operation at relatively high electron energies (up to 100 keV) necessary to achieve 1.5-2 MW power

Summary / Russia

Summary until 2009

• Maximum Efficiency=60 % (0.6MW,CW mode)

170GHzGyrotron

• Repetitive operation : 0.8MW/600s (every 30min)

• ITER basic requirement (1MW/800s)

• Output Energy>250GJ

Repetitive Operation 800kW/600s/every 30min/8 days

High Reliability was demonstrated.

Photo interlock

Vbody

Vanode

Ibeam

RF

1ms 60s

5 kHz power modulation (anode modulation)

ITER target5kHz/50s(0.5MW-1MW) mod.Attained5kHz/60sFull ~1.1MW mod.

Vcathode

60s

Dual Frequency Gyrotron (170GHz/137GHz)Short pulse (<1ms), without CPD

170GHz(TE31,11)

136.8GHz(TE25,9)

P>1MW at Ic=45A

Preliminary

Vbeam=70kVBc & Vak optimized

Output Beam coupleswith transmission lineusing same mirrors.

Dual Frequency Gyrotron

Mode contentHE11 95.0 %LP02 0.4 %LP11

odd 0.8 %LP11

even 0.8 %Mode contentHE11 91.1 %LP02 1.1 %LP11

odd 3.5 %LP11

even 0.2 %

Long range TL

Polarizer Miter bend

Miter bendW/GSwitch

Gyrotron Beam profileat TL input

Beam profileat TL output

Long TL dummy load

High Power Transmission Experiment

High Efficiency high power transmission was proved onITER-relevant transmission line

KIT – University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association

Institute for Pulsed Power and Microwave Technology

www.kit.edu

2.2 MW Operation of the European Coaxial-Cavity Pre-Prototype Gyrotron for ITER

AcknowledgmentThis work was supported by Fusion for Energy under the grant contract No. F4E-2008-GRT-08(PMS-H.CD)-01 and within the European Gyrotron Consortium (EGYC). The views and opinions expressed herein reflect only the author’s views. Fusion for Energy is not liable for any use that may be made of the information contained therein.The authors are grateful to Dr. T. Shimozuma from the National Institute for Fusion Science (NIFS), Toki, Japan, for the supply of the silicon-nitride-Brewster-window.

G. Gantenbein1, T. Rzesnicki1, B. Piosczyk1, S. Kern1, S. Illy1, J. Jin1, A. Samartsev1, A. Schlaich1,2 and M. Thumm1,2

Karlsruhe Institute of Technology (KIT), Association EURATOM-KIT, 1 Institute for Pulsed Power and Microwave Technology (IHM), 2 Institute of High Frequency Techniques and Electronics (IHE), Kaiserstrasse 12, 76131 Karlsruhe, Germany, e-mail: [email protected]



depressedcollector

output window

RF outputsystem

launcher

cavity

electron gun

sc-magnet

RF-beam

Introduction •Development of European 2 MW, 170 GHz, CW gyrotron• Design based on pre-prototype gyrotron operated at KIT (~ms)• Coaxial cavity gyrotron (high-order volume modes with reduced mode competition and voltage depression)

Operating cavity mode TE34,19Frequency 170 GHzRF output power 2 MWBeam current 75 AAccelerating voltage 90 kVVelocity ratio ~ 1.3Cavity magnetic field 6.87 TEfficiency with SDC > 50 %



Recent Modifications of the Gyroton Set-up

• Additional NC coil to operate at the nominal field: 6.87 T (adaption of the electron gun’s anode)• Installation of new beam tunnel to suppress parasitic oscillations• New q.o. output coupler installed: launcher optimized with a novel optimization method



Operation with Modified Beam Tunnel and Nominal Magnetic Field

• Up to 2.2 MW at Uc= 93 kV and Ib= 80 A• Good agreement with numerical simulation (multi-mode self consistent code)• Operation of the gyrotron with significantly improved stability and purity• No spurious parasitic oscillations excited outside the gyrotron cavity• Stray radiation, Ohmic losses and absorption in the RF output window: 10 % • Total measured stray radiation losses: ~7 %



Design of the Launcher• Novel optimisation method based on quasi-optical propagation theory of modes inside oversized waveguides• New code employs the solution of the scalar diffraction integral equation and performs a numerical optimization of the launcher surface >> complicated surface contour • Conversion efficiency to Gaussian beam: ~96 %• Microwave stray radiation losses inside gyrotron ~2 %• Conversion performance of the new q.o. RF system high for several high order modes 130 -210 GHz if caustic radius similar to TE34,19 mode (92 - 96 %)

Calculated microwave beam propagation in the improved RF output system



Verification of the RF Output System• Low power cold-test measurements with TE34,19 mode at 170.325 GHz• Very good agreement observed: ~96 % conversion efficiency confirmed by Gaussian mode content analysis of the measured patterns• Final validation of the performance of the q.o. RF output system: intensity profile of gyrotron RF beam • Phase reconstruction of “hot” RF beam at window : ~96 % Gaussian mode content

Calculation (top) and low power measurement (bottom) of the RF beam profile at a distance of 500 mm from the gyrotron window.

Calculation (left) and high power measurement (right) of the TE34,19 beam profile

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SUMMARYLast years - great progress in ITER gyrotron development:� 1 MW very long pulses

Japan – 1MW/800 sec; 0.8 MW/3600 sec Russia – 1MW/570 sec; 0.8 MW/800 sec

� Very high efficiency 53-55% at 1 MW power� Reliability tests� Possibility of fast power modulation� Successful tests of high-power models (EU, Ja, Rus)

e.g. Europe – 2.2 MW (5 ms)+ Dual and multi-frequency gyrotrons in development

- 3 tubes 0.9 MW/140/105 GHz/sec gyrotrons delivered to ASDEX-Upgrade (Rus)- 170/137 GHz gyrotron tested in relatively short pulse (Japan)- development of multi-frequency gyrotrons in progress

1 Institute of Applied Physics RAS, Nizhny Novgorod, Russia ......2 GYCOM Ltd, Nizhny Novgorod,...

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Transcript of 1 Institute of Applied Physics RAS, Nizhny Novgorod, Russia ......2 GYCOM Ltd, Nizhny Novgorod,...