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5. SUMMARY OF AVAILABLE EQUIPMENTS

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  • 5. Summary of Available Equipments

5-2. Nuclear Fusion Dynamics

(1) QUEST   (2) Research Facilities for Nuclear Materials
(3) Research Facilities for Plasma facing Materials for Fusion Reactor
(4) Plasma Assembly for Nonlinear Turbulence Analysis (PANTA)

( 1 ) QUEST

Contact : Hiroshi Idei

Higher beta operation than conventional tokamak can be realized by spherical tokamak. The QUEST research project is planned to pioneer new long-pulse-operation regime and establish its academic base. We aspire for leading research to development of advanced nuclear fusion reactors. Long-pulse-operation of tokamak is an essential theme not only seeking steady state tokamak reactor but also providing new findings for the invention of magnetic fusion reactor. Our group has proposed research topics as follows:

  • To demonstrate and establish new methods to drive plasma current by electromagnetic waves and mode-converted electrostatic waves.
  • To improve diverter concepts and to establish the way of controlling particles and heat loads during long duration operation.
  • To comprehensively establish recycling control based on control of wall temperature, and advanced wall control under high plasma performance.

Our target parameters are;

Phase I :
(quasi-steady state: Ip = 20-30 kA, PRF = 450 kW)
Phase II :
(quasi-steady state: Ip = 100 kA, PRF = 1 MW)
(Pulse: Ip = 300 kA, ne = 4×10-19 [m-3], PRF = 3 MW)
【 The QUEST spherical tokamak 】
Parameters Design >Accomplished
Major radius 0.68 m 0.68 m
Minor radius 0.40 m 0.40 m
Aspect ratio 1.7 1.4
Elongation 1.6 ~ 1.2
Troidal field 0.25 T (at R=0.64 m, steady state)
0.5 T (at R=0.64 m, Pulse)
0.25 T (at R=0.64 m, steady state)
Plasma current 20 kA (Phase I)
100 kA (Phase II)
100 kA (< 2s)
2 kA (long pulse)
Duration time Steady state 6 h (2 kA, PRF = 40 kW)
Vessel size
Hot wall
Diameter d = 2.8 m
Height h = 2.8 m
Hot (100–500 degree Celsius) wall has beenll installed.

QUEST

Current Drive Devices
◆ Klystron
  Specification
Frequency 8.2 GHz
Klystron 1 systems
Output power < 25 kW
Pulse CW

◆ Gyrotron
  Specification
Frequency 28 GHz
Gyrotron 1 systems
Output power < 200 kW
Pulse < 2 s

Measurement
Device Target Information
Flux loop Plasma position control
Vacuum pumping system Pumping of vacuum vessel
Multi-channel visible spectrometer Profile measurement of line emission Spectrometer (Focal distance:1m) Cooled CCD
Visible monochrometer Analyzing ionization, Zeff, impurity in plasma P-250
Microwave interferometer Line-averaged electron density
Movable SOL probe Density and temperature in SOL
Gas injection system Gas puff, Mass flow meter H2, He
Ionization gauge Fast ion-gauge
X-ray pulse height analyzer Tangential Hard X-ray
High speed camera Monitoring Plasma cross-section Photron Nova S6
Thomson scattering system Electron temperature and density YAG, 10 Hz

1) X-ray pulse height analyzer
Specification
Number of channels 4 ch
Number of energy channels 1024 ch
Energy resolution ~ 1.2 keV @122 keV
Sampling time > 1 ms
Energy range 30 ~ 200 keV
2) 4 mm micro-wave interferometer
Specification
Oscillator Frequency multiplier (9.3 -> 75 GHz)
Model AMC-12RHOA
Frequency 75 GHz
RF output 0.2 W
Interferometer type Heterodyne
Detectors Harmonic mixer, IQ detector
3) Visible monochrometer
Specification
Focal distance 250 mm
Aperture F = 4.5
RLD 30 Å/mm
Resolution 0.6 Å (FWHM at 5460.74 Å)
4) Movable Langmuir probe
Specification
Material Tungsten
Melting point 3387 ℃
Electrodes Depending on the probe head
Probe voltage -100 ~ 100 V
Sweep frequency 1 kHz
Number of channels Depending on the probe head
Moving distance 45 cm from the vacuum vessel
5) Plasma spectrometer
Specification
Spectrometer Acton AM-510
Model Czerny-Turner
Focal distance 1 m
Aperture ratio F/8.7
RLD 7.4 Å/mm
Wave length range 1850-8000 Å
Resolution 0.12 Å
Detector ICCD-1024MLD (Pertier Element)
CCS effective area 23.5 mm × 6.7 mm、 900 × 256 pixels
6) Thomson scattering system
Specification
Laser Nd:YAG
Repetition frequency 10 Hz
Number of measurement points Six points. Another 6 points can be measured by changing the position of optical fibers.
Spectroscopic method Polychromators with 6 interference filters

( 2 ) Research Facilities for Nuclear Materials

Contact : Hideo Watanabe

Handling of the neutron irradiated samples in RI controlled area is essential for development of nuclear fusion reactor, and the safety research of the existing nuclear power plants. In the nuclear fusion dynamics section, introduction and maintenance of the experimental devices (in which handling of radioactive materials are possible) are advanced in Maidashi area from the Heisei 25 fiscal year.

Since handling of RI has restriction of a nuclide and quantity, please consult in advance.

1 ) Research Facilities in RI Controlled Area. (Maidashi Campus)
1-1 ) Nano-Cluster Evaluation System (Cs corrected STEM)

The JEM-ARM200F(cold FEG type) in the hot area can be used for neutron irradiated samples. The microscope with a STEM Cs corrector incorporated as standard, and the mechanical and electrical stability enhanced to the utmost limit, achieves the world's highest level STEM-HAADF resolution of 78 pm. And as the Cs-corrected electron probe has an increased current density, which is one order larger than conventional FE TEMs, the elemental analysis at the atomic-level becomes possible, along with an extremely enhanced throughput.

(EELS for PWI studies) Surface analysis using Electron Energy Loss Spectroscopy (EELS) is the one of the advanced technologies for PWI studies. The cold FE gun, which incorporates a new vacuum system, can be put in use immediately after flashing, unlike the previous cold-FE gun. In addition, the optical source is small enough to allow even higher resolution images. The narrow energy spread that is characteristic of the cold FEG enables high energy resolution EELS analysis and also decreases chromatic aberration.

Item Specification
Resolution 0.1 nm (HAADF)
Voltage 80 - 200 kV
Gan Cold FEG type
EDS system 100 mm2 (SDD type)
EELS system EnfiniumSE
1-2 ) Others

For microscopy, twin jet polishing and ion milling apparatus in the lot lab are also available.

2 ) Research Facilities in Chikushi Campus (RI non-controlled Area)
2-1 ) High Energy Ion Generating Apparatus

Tandem type 1MV Accelerator. This apparatus can be used for the non-destructive analyzing experiment, such as Elastic Recoil Detection (ERD), Rutherford Back Scattering (RBS), Channeling, Particle Induced X-ray Emission (PIXE), and for the irradiation experiment to produce damage to the specimen, which greatly contributes to the study of plasma facing materials and structural materials for the fusion reactor.

Item Specification
High voltage Cockcroft-Walton
Available Terminal Voltage 0.1 - 1.0 MV
Maximum Beam Current 4He2+ 0.5 puA (3.0 MeV), 58Ni3+ 2.0 puA (4.0 MeV)
Analysis Function Rutherford Back Scattering (RBS)
Channeling
Elastic Recoil Detection (ERD)
Particle Induced X-ray Emission (PIXE)
Irradiation Capacity High Dose Irradiation by Heavy Ion (~ 100 dpa)
Irradiation Temperature Range RT ~ 800℃
2-2 ) Others

 SEM, Low energy ion irradiation apparatus, Hardness testing machine, TDS, Ion Milling apparatus are also available for the study of fusion reactor materials.

( 3 ) Research Facilities for Plasma Facing Materials for Fusion Reactor

Contact : Kazutoshi Tokunaga

1 ) Electron Beam Thermal Loading Simulator

This simulator can be used to simulated thermal heat load to divertor plate, limiter and first wall to steady state plasma discharge. This is used for investigation of fundamental process of melting, evaporation and thermal degradation and evaluation of high heat flux materials.

◆ Main Capacities
Item Specification
Electron source Pias type
Beam energy 20 keV (max)
Power 3 kW (max)
Beam current 150 mA (max)
Beam diameter 1 ~ 20 mmΦ
Beam duration 0.1 s ~ continuous
Vacuum degree 7 x 10-6 Pa
◆ Equipped devices
Item Specification
Thermoviewer Two dimensional surface temperature measurement, 3000 ℃ (max)
Radiation thermometers Two color type, 450 ℃ ~ 1100 ℃, 1000 ℃ ~ 3100 ℃
Quadrupole mass spectrometer Emitted gases and atom measurement
Ion Gun Hydrogen isotope irradiation, 0.5 keV ~ 5.0 keV
Visible spectorpmeter Emitted atom and ion measurment
2 ) Thermal Desorption Spectroscopy system (TDS)

Thermal Desorption Spectroscopy (TDS) is used to investigate desorption gas from a heated sample using a mass spectrometer. Information about identification of molecules, the amounts of adsorbed molecules and process of desorption on the surface is obtained.

Item Specification
Mass Spectrometer Quadrupole M.S.(SEM : 1 ~ 100 a.m.u.)
Temperature ~ 1400 ℃
Sample size 0 mm x 10 mm x 50 mm (max.)
3 ) Sample Transfer System for Material Experiment (STSME)

This system can be transferred to vacuum wall in the QUEST without breaking the vacuum condition of the plasma chamber. This system is used for investigation of hydrogen absorption, impurity deposition and radiation damage on material surface by plasma exposure.

Item Specification
Vacuum degree 2x10-8 Torr
Prove head size 30 mm x 30 mm x 50 mm
Active cooling > 1.5 kW
Temperature measurement by thermocouple 6 pieces

( 4 ) Plasma Assembly for Nonlinear Turbulence Analysis (PANTA)

Contact : Akihide Fujisawa

The linear magnetized plasma experiment PANTA (Plasma Assembly for Nonlinear Turbulence Analysis) is available for the basic study of plasma turbulence. PANTA creates a linear plasma column with overall length 4 m and radius 6 cm. An advantage is the ultra-multi-channel Langmuir probe system which allows spatiotemporal structure (e.g. the streamer) measurement of plasma turbulence with high spatial and temporal resolutions.

【 PANTA 】
Item Specification
Vacuum Vessel diameter = 0.45 m, overall length = 4 m,
Background pressure ~ 1 x 10-4 Pa
Plasma Production Helicon wave power source (1 - 10 MHz, 10 kW),
Electron cyclotron wave power source (2.45 GHz, 5 kW)
Plasma Parameter Helicon-Ar-plasma : electron temperature ~ 2-4eV
Electron density ~ 0.2 x 1019 m-3, magnetic field < 0.15 T
Diagnostics Manometer, Quadrupole mass spectrometer,
Langmuir probe array
(spatial resolution ~ 4 mm, temporal resolution ~ 1 μsec, Total 192ch available)

 

 

 

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