Transcript Slide 1

Examples of ITER CODAC
requirements for
diagnostics
S. Arshad
Colloquium on ITER-CODAC
Plant Control Design Handbook
and EU Procurement of
Control and Instrumentation for ITER
28 October 2008
Colloquium on ITER-CODAC
28/29 October 2008
1
Hot fusion plasma can be contained in a magnetic
field
Colloquium on ITER-CODAC
28/29 October 2008
2
Containment improves with size – ITER will be much
larger than today’s machines
R a
JET: World’s
largest tokamak
R (m)
6.2
a (m)
2
IP (MA)
16
Bt (T)
5.3
Paux (MW)
40 – 90
Pa (MW)
80+
Q (Pfus/Pin)
10
Prad (MW)
48
tpulse (s)
400+
ITER
New engineering and physics challenges for
measurement and control
Colloquium on ITER-CODAC
28/29 October 2008
3
Wide range of diagnostics needed to diagnose
fusion plasma
Port type
No. used
Equatorial
Upper
Lower
9
12
9
Additionally many
measurements inside
vessel
UPPER PORT 10
• X-Ray Survey
• Imaging VUV Spectroscopy
UPPER PORT 11
• Edge Thomson
EQUATORIAL PORT 11
• X-Ray Crystal Spectroscopy, array
• Divertor VUV Spectroscopy
• X-Ray Survey
• Core VUV Monitor
• Neutral Particle Analyser
• Reflectometry
EQUATORIAL PORT 9
• MSE
• Toroidal Interferometer
/ Polarimeter
• ECE
• Wide Angle TV/IR
DIVERTOR PORT 10
• X-point LIDAR
• Divertor Thomson
Scattering
• H-Alpha Spectroscopy
DIVERTOR PORT 8
• Divertor
Reflectometry
Colloquium on ITER-CODAC
28/29 October 2008
4
The EU will supply a range of diagnostics to ITER
Ports for diagnostics & heating systems
General scheme for processing of diagnostic data
Analog
processing
ADC
Controller
Real-time
processing
Machine
protection &
plasma control
About 40 diagnostic systems installed in ports and
inside / outside the toroidal chamber; 13 to be
supplied by the EU:
•
•
•
•
•
•
•
•
•
•
•
•
•
Off-line
processing
Physics
studies
Processed data from diagnostics (Courtesy of EFDA-JET)
Plasma wall
interaction
Plasma shape &
neutron profile
Temperature &
density profiles
Wide-angle viewing system
Magnetics
Radial neutron camera
Core Thomson scattering
Bolometers
Core charge exchange recombination spectrometer
Hard X-ray monitor
Plasma position reflectometer
Pressure gauges
Thermocouples
LFS collective Thomson scattering
High-resolution neutron spectrometer
Gamma-ray spectrometers
Colloquium on ITER-CODAC
28/29 October 2008
5
The magnetics diagnostic is a large system for
basic plasma control, machine protection and
physics studies
Purpose
Prototype magnetics sensors
Control Protection Physics
• Determine plasma current,
shape and movement
• Measure thermal energy of
plasma
• Detect and quantify plasma
instabilities
• Reconstruct magnetic flux
surfaces (equilibrium)
• Detect and quantify any
current flowing from plasma
into vessel









In-vessel pick-up coil


Ex-vessel pick-up coil
In-vessel pick-up coil
• Diagnostic comprises
pick-up coils, flux loops,
Rogowski coils
• ~1050 sensors inside the
vessel (shown in figure)
• ~600 additional sensors
outside vessel
Hall probe
Copper or Stainless
steel braided sheath
2nd Copper layer
(=8.3 mm,
pitch=1mm)
1st Copper layer
(=5.5 mm,
pitch=1mm)
Polyimide ribbon
Copper Core
Glass fibre filler
Glass fibre filler
Glass fibre filler
External rogowski coil
Colloquium on ITER-CODAC
28/29 October 2008
6
Overview of magnetics signal processing
Event
triggers
dB/dt
Int
B
Off-line
processing
Physics studies
Real-time
processing
Control & protection
ADC
Amp
dB/dt
• Around 1650
sensors in total
• Digital or
analogue
integrators
• Amplifiers
• Slow (4kHz) ADCs
for basic equilibrium
• Fast (1 MHz) ADCs
for instabilities
• Typically with optical
isolation
• Data stored for
specialist off-line
studies
• Real-time signals
distributed to other
plant systems (power
amplifiers for
tokamak magnets,
machine protection
systems)
ALL NUMBERS ARE INDICATIVE
Colloquium on ITER-CODAC
28/29 October 2008
7
Plasma current and shape (1/2)
• Plasma current measured by
integrating magnetic field over
poloidal contour (Ampere’s law)
• Plasma shape characterised by
gap between plasma boundary
(solid red line) and first wall
• Shape controlled by changing
current in tokamak coils
Colloquium on ITER-CODAC
28/29 October 2008
8
Plasma current and shape
Event
triggers
dB/dt
Int
B
Similar arrangement
for 410 in-vessel
Rogowski coils
feeding vessel
current
reconstruction code
Off-line
processing
Physics studies
Real-time
processing
Control & protection
ADC
Amp
dB/dt
• Around 750
• Integrated signals
• Individual signals
sensors (of
typically sampled at
integrated (typical
which 380 intime constant 100ms; 4kHz (20kHz at
vessel)
events)
output +/-5V) and
• Typical raw
•
Typically 16 bit ADC
digitised separately
signal from
with dithering, 25 bits
• Integrated signal in
2
0.05m pick-up
without)
range of 0.06Vs;
coil in +/-60mV
frequency response
range under
~10kHz; drift
normal
<0.35mVs after pulse
operation; +/-5V of 3600s
at disruptions
• Summing integrator
for ‘hardware’
calculation of plasma
current (10kA-15MA
range, 1% accuracy)
• Calibration of signals
• On-line data validation checks and corrective
actions (e.g. voting system with 3 toroidal positions)
• Second plasma current calculation from individual
signals
• Plasma boundary and plasma-wall gaps
determined (1-2cm accuracy) 100k FLOP/cycle
(10ms cycle time  0.01GFLOPS)
• Control signals generated for gap control and
distributed to power amplifiers for tokamak coils
• Data stored for specialist off-line studies including
full equilibrium reconstruction combining data from
other diagnostics (20GB per pulse)
ALL NUMBERS ARE INDICATIVE
Colloquium on ITER-CODAC
28/29 October 2008
9
High frequency instabilities – analysis & control
Event
triggers
dB/dt
Int
B
Off-line
processing
Physics studies
Real-time
processing
Control & protection
ADC
Amp
dB/dt
• Around 270
high frequency
sensors (with
response up to
100kHz)
• High frequency
results in relatively
strong (voltagerange) signals which
can be recorded
directly with low gain
• Frequency response
up to 300kHz
• RMS signals from
summing amplifiers
may for rapid
overview of
instabilities or for
event triggering
• 16 bit resolution likely
to be adequate
• Sampling rates up to
1 MHz
• Event triggering to
manage data
quantities
• Data stored for
specialist off-line
studies; of order 50GB
per pulse
• Real-time signals for
feedback control
(resistive-wall modes)
• Additional, more
specialised, event
triggers
Similar arrangement for
around 380 in-vessel
sensors for plasma
vertical speed control;
10kHz sampling; 30GB
storage; 1GFLOPS
ALL NUMBERS ARE INDICATIVE
Colloquium on ITER-CODAC
28/29 October 2008
10
Overview of requirements for some diagnostics
System
Electronics
ADCs
Magnetics
• 1200 integrators
• 650 amplifiers
• 1600 slow ADC
110GB
channels (20kHz)
• 270 fast ADC
channels (1 MHz)
Bolometry
• 500 lock-in amplifiers
(50kHz)
• 500 ADC
channels
360MB
Charge
Exchange
• Read-out from up to
75 CCD cameras
(100 spectra/sec.
560 pixels each)
• N/A
30GB
• 150 ADC
channels at
20GSa/S; 10-bit
samples
100MB
Core
LIDAR TS
Storage (per pulse)
ALL NUMBERS ARE INDICATIVE
Colloquium on ITER-CODAC
28/29 October 2008
11