F. Durodié18-Jan-2005JET-EP ITER-Like Antenna PB2005/1 JET-EP ITER-like ICRH Antenna - Technical Status Project Board 18 January 2005 11:00- 16:00 JET

F. Durodié 18-Jan-2005JET-EP ITER-Like Antenna PB2005/1

JET-EP ITER-like ICRH Antenna - Technical StatusProject Board 18 January 2005

11:00- 16:00 JET

F. Durodié


Capacitors• Pressure Drop Measurements OK

– Independent of capacitor position

– Measurement 0.25 bar @ 16 l/min slightly below valueassumed for the design of the cooling circuit (0.4bar)


Capacitor (Art. 7 Contract)• Final Capacitor modified from the CfT version

– Changes due to choice of Actuator as well as Assembly issues

– Impact on Art. 7 contract : below CfT capacitor resulting from R&D

Thin the copper “rear part of the capacitor outer envelope” and reinforce with a

stainless steel external cylinder

Torsion lock mechanism for the rotation of the variable electrode to reduce stress

in the internal bellows

Stainless steel corona rings

Re-enforced Ceramic to Cu-sleeves brazes

Interface with inner-VTL : strong but off-axis pivot-points


Final Capacitor• Capacitor Design Evolution – Final Design

– Relatively large impact on contract due to extra SS welding and associated QA.

– Extra testing of bellows lifetime and OFHC Cu properties

New interface with “Pivot-ring”-assembly allowing to rock on axis while strong enough

to take the torque (tight tolerances)

Strengthened Weld between capacitor body and water-chamber

Extra bellows in order to obtain monitored vacuum interspace

(containment tube and mechanical stop (grey) shown for information (not part of delivery))Stainless Steel (blue) Water pipes with

inconel (magenta) ends

Modified water-chamber to allow welding of remaining pipe work during assembly using orbital welding tool

Modified interface


• RF Measurements of the (vacuum) 8x8 Antenna Scattering Matrix [10/06/2005]

– Adaptors (x8) – Final drawings done – Contact rings (x16) – Final drawings done

• Calibration of RF Capacitor Voltage Probes [10/06/2005]

– Adaptor (x1) – Final drawings done – Contact ring (x2) – Final drawings done– Support for inner conductor of adaptor (x1) – Final drawing to be processed– Dummy capacitor (x1) – procurement phase– Supports for dummy capacitor (2x1) – Final drawing to be processed

• High Voltage Test (each RDL powered in turn)– Short circuits (x3) – Final drawings done

TCDI for these three topics will be submitted when all final drawings are ready

• “Loading” the antenna (RF characterization and Matching studies) [24/06/2005]

– Salty water tank (x1) – detailed design in progress– Support structure for water tank (x1) – detailed design in progress

• RF Characterisation of the APTL and simultaneous matching of all RDLs [24/06/2005]

– Low power service stubs (x4): inner and outer conductors, supports, flange– Impedance transition (x4)– T-junction/feeding (x4) Detailed design in progress

• RF Electronics [8 week delivery]

– Tests of 75dB amplifiers ongoing : noisy -> 60dB -> need to operate at 5W (4 x 1W).

Testbed Equipment - status


Miscellaneous Items• VCW

– Test of Brazed Joint successful up to 150%of requested mechanical loads

• Seesaw and Pivot Ring– Comments back from TCD-I– Aim at launching CfT end of January

• Inner VTL– Capacitor Cooling Pipes

• Stress Analysis done by ENEA : No problems apparent• Needs to be transferred to Mecagest after final config control

– Lifting tools : (small) Modifications required

• HPP– Successful casting of straps– Operation to restart 2nd half of February– (report by Rick Goulding)

• Ex-Vessel Support– Testing of Spring Dampers has started– Top Assembly Jack Issue

• Antenna In-vessel Components– Redesigned water chamber and

Strap Cooling Pipe expansion boxes


Actuators – Pressure Vessels• Operating and Failure conditions were agreed with the Operator in order to perform a

3rd party design validation

• Drawings were finalized and Call for Tenders launched for Actuators, Pressure Vessel Parts and Pipe Spools.

– Actuator : minor technical comments returned : drawings are corrected

– Pressure Vessel Parts :• Front and back flanges with pipe penetrations require the use of inclusion tested material• The present design favors extra material and machining above welding the pipes on the front/back flange• It is feared that this may impact substantially on cost and delivery time• Project team are assessing the consequences of welding the pipe penetrations on the flanges• Tender is on hold until welding issues are clear and instruct tenderers accordingly

• The positions sensor is not available as a standard catalogue item from Penny & Giles any longer :

– however all tooling to produce position sensors is still available

– Penny & Giles have agreed to produce a batch of position sensors

• Drawings of Drive-Rods available for review


Assembly

• Detailed preparation of the Assembly is on-going

– ICM : Robert Warren

– On Site Assembly/Welding of the Actuator is a New Requirement since last PB

• Quickest and Closest monitoring of QA aspects -> minimization of impact on cost and time

• Plan is not yet updated ! (8 weeks assumed)

– Welder Qualifications / Training

– PPS’s

– Connection with APTL Piping / Swagelocks

• Final layout + 14° bend : starting this weeks

– Several Jigs need to be designed in support of the Welding activities for Inner-VTL + Actuator Pressure Vessels Assembly

– Planning of Break-in/Function tests for the Actuator are required.


Conclusions• The Design phase for the antenna components is completed and the

components are well into their manufacturing phases

– Exceptions : Actuator related packages, Capacitors, RF Probes, See Saw / Pivot Ring

• Manufacturing phase of various components still return questions from manufactures that need attention form the project team and in some case may require (minor) redesign :

– AIC : Water-chamber, Strap Cooling Pipe expansion boxes

– EXS : Top (Assembly) Jack, Lifting Frame

– VTL : Lifting Tools, Assembly Jigs.

• The follow-up of the procurements as well as the preparation of the Assembly and Testbed phase of the antenna are presently becoming the main focus of the project team

• The full/detailed impact of the Assembly in the planning is still outstanding.


Status Matching and Arc Detection Studies• Simulation of a/the Matching Algorithm is mainly done using a Matlab-

Simulink tool developed by ERM in which the outcome of a more theoretical analysis is tested/tried.

– Matching of 8 independent capacitors of 4 cross-coupled RDLs proved to be a very difficult mathematical problem :

• Complicated topology of “matching” surfaces + the human brain is not well suited to think in an 8-dimensional space [ref Ringberg April 2004, SOFT September 2004].

• Mathematical analysis of single RDL with cross-coupled straps revealed some insight in the “knobs” to be used : matching to a complex impedance at the conjugate-T junction.

• At present the Matching Algorithm is making use of the toroidal symmetry : 4 capacitors of one toroidal half are “slaved” to the 4 capacitors of the other half.

– To be investigated / quantified : symmetry assumptions.

– The antenna impedance matrix is obtained from MWS modelling of the antenna array in front of a “plasma-like” dielectric.

• Up to now only one matrix was used : H-mode and ELMs are simulated by scaling Real and Imaginary parts of the Impedance matrix “appropriately”.

• Outstanding : interpolation from different matrices for different positions of the “plasma-like” dielectric.

– There are many settings possible (phases, Zref, gref) : only a brief exploration is available, no real optimisation was tried yet.


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No feedback during ELMs


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Drift of capacitors during ELMs


Matching Simulations - Overview


Matching Simulations - Overview

• Below 35 MHz matching to a Zref with a small inductive part is not possible due to limitations in the 2nd stage matching (phase-shifter).


Arc Simulation

• Arcs are simulated by putting a small inductance (20 nH) in the circuit at the arc location

• Arc locations shown for RDL P. Similar locations for RDL Q.


Arc Simulation

• Preliminary results !

– Example : TS type of Arc at conj-T on RDL P

– ! Very modest variations of the VSWRs !• The VSWR of the line with the arc is almost not

changed ! (OK ?)

– If confirmed : clever arc detection schemes are required based on

• symmetry• Voltage and phase relationships for normal

conditions• …

• Next meeting foreseen on 27/1 (tbc)


Matching and Arc Simulation Conclusions• “Master-Slave” algorithm seems to work across the frequency band, however

:

– There may be no operation below 35 MHz at an appropriate complex matching impedance

– Non-idealities have not been introduced/quantified yet. It may be possible to split the matching approach in two parts :

• “far away” from the match -> master-slave• “closer” to the match -> 8 independent capacitor control

– The feedback signals were derived from “perfect knowledge” of the RF quantities involved in the circuit analysis

– More realistic impedance variations are still outstanding (MWS Modelling)

• Arc Detection : the analysis tool is just about ready

– Only the “TS-like” arc has been reported so far and the results are not really understood

– If confirmed it is likely that arc detection based on VSWR will not be sufficient

• Much more work and analysis needed– Algorithm : Optimization in the spaces of {Phases, Zref (top, bottom), gref}

– Arcs : Catalog of reference Arcs and arcing conditions (matched, off match, elms …)

– Algorithm (& Arc) : work from real signals including non-idealities



Testbed equipment - status

“Loading the antenna”

Scattering Matrix + Probe

Calibration

High Voltage Test

Matching all RDLs

Conceptual design

Done Done Done Done

Detailed design In progress Done Done In progress

Drawings status Conceptual Final Final Conceptual

Cost estimate (1) 22 kEUR 14 kEUR 4 kEUR 4 kEUR

+ 15 kEUR (2)

Planned delivery date

24/06/2005 10/06/2005 10/06/2005 24/06/2005

(1) Subject to changes after detailed design and special requests (safety, waste,…)Transport not included

(2) If transmission line elements not “on loan”

Documents

F. Durodié18-Jan-2005JET-EP ITER-Like Antenna PB2005/1 JET-EP ITER-like ICRH Antenna - Technical Status Project Board 18 January 2005 11:00- 16:00 JET