Latest Changes at ITER - PowerPoint Presentation

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Latest Changes at ITER - PPT Presentation

ITER Organization J A Snipes ITER New Organization Structure Human Resources As of end September 2011 the IO has a total of 470 staff members with 299 professional and 171 technical support staff members ID: 405867

plasma iter analysis scenarios iter plasma scenarios analysis current stac eccd optimization 2011 scenario itpa control staff icd mid

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Slide1

Latest Changes at ITER

ITER Organization

J A SnipesSlide2

ITER New Organization StructureSlide3

Human Resources

As of end September 2011, the IO has a total of 470 staff members with 299 professional and 171 technical support staff members;

Since January, the IO has posted 35 positions; more than 700 nominated applications have been received and 87 candidates have been interviewed. 23 staff members’ employment contracts started (19 Professional staff, 4 Technical Support staff) while 22 persons left the IO. With the foreseen recruitments and departures, the total staff number will be 473 by the end of 2011.

Professional staff

Support staff

Total

16 420EU179125304IN131629JA28735KO21526RU19322US231134Total299171470

P Staff Distribution by MembersSlide4

STAC discussed cost-saving proposals by

IO: eliminating the 19th TF coil and one CS module, and further reducing the scope of the coil cold test at 80K to the first two coils

STAC

considers

the elimination of the spare TF coil and CS module to be a high risk

STAC still

recommends testing all TF, PF and Correction Coils at 80K and cold testing the CS modules at 4K and full currentSTAC recommends a final analysis by an expert group to settle the issues of conductor qualification, cold tests, and quench protectionSTAC is pleased with the elaboration of ITER operation scenariosMore work is required to analyze the compatibility of ITER core plasma operating modes with divertor requirementsSTAC recommends that the IO examine a range of scenarios for early operationsResults of STAC-10 Meeting (1)Slide5

STAC recommends that a control strategy/methodology, together with diagnostic requirements, be developed to avoid disruptions and accurately predict impending disruptions and to deploy the mitigation sequence

STAC recommends that IO should be a strong advocate for physics R&D and play a more active role in coordinating and prioritizing the R&D opportunities in the fusion community

STAC considers the unexpected recent test failures of the CS and TF coils conductors to constitute a very serious issue, with substantial implications for schedule and

cost

STAC believes that the triangle of scope, schedule, and cost is challenged by recent

developments

Results of

STAC-10 Meeting (2)Slide6

Future Analysis

Scenarios have been established satisfying basic requirements for hybrid and steady-state operation in ITER

These scenarios will be used in future analysis to address:

development of optimized equilibria more appropriate to the hybrid and steady-state scenarios – implications for PF control, MHD stability and

β-limit

studies of scenario evolution under PF feedback control to obtain complete descriptions of the power supply requirements for such scenarios

– analysis of control actions for advanced scenarios

simulation of scenarios in which the H&CD systems and current profile are coupled via feedback control loops to maintain the required form of the current profile MHD stability analysis to constrain both the pedestal parameters and the β values which are incorporated in the scenariosSlide7

Future Analysis

Guidance in future development of advanced scenarios will rely strongly on further experimental R&D – particularly critical in candidate steady-state scenarios:

transport assumptions, including existence of ITB – importance of magnetic shear

rotational shear; likely density profiles

oundary

conditions for transport analysis, ie pedestal parametersMHD stability in pedestal and core – constraints on acceptable current profiles and maximum pedestal parameters; maximum βN without RWM controlfeedback control of current profiles to maintain enhanced confinement and MHD stabilityvalidation of current drive capability of H&CD systemsIn longer term, compatibility with divertor constraints, energetic particle mode stability etc Slide8

STAC-11 report has not yet been finalized so only a general impression can be given at this time with no conclusions

Recent tests of the CS conductor indicate that only 40000 full cycles of the CS may be achievable over the lifetime of the CS but at 70% of full current there is no limitation in the number of

cycles

Impact of reduced

current in the

CS on scenarios is being studied

IO will attempt to qualify a more robust CS conductor in parallel

May lead to a 6 month delay to meet the Project Requirements for the CSSTAC suggested possibility of 30% degraded top and bottom CS modules then sufficient time to improve the central four CS modules so that schedule could be maintainedModeling is required to assess this possibilityReport from STAC-11 Meeting (1)Slide9

DG Motojima proposed

eliminating the CFC divertor and starting with the full W divertor as a cost saving measureWill require at least 1 year to develop a basic design for a W divertor

Proposed modification of inner wall blanket shield modules to improve neutron shielding of TF coils

Some

deferral of heating systems is being considered while ensuring > 60 MW for He

H-mode operation

eferral of up to 80% of the diagnostic back-ends is being considered as a cost saving measure during the construction phaseReport from STAC-11 Meeting (2)Slide10

Proposed Blanket Design to Improve Neutron Shielding of TF Coils

Current

reference

case with

thickened inboard modules

Straighten Inboard Modules (+2.5 kW ± 1 kW)~19.5 kWBM 1 to 5 identical: substantial cost savingDesign and analysisManufacturingTolerable EM loads on BM 1Reduce gaps from 10-14 mmto 8 mm in the inboard(-0.75kW ± 0.25 kW)~18.7 kWIncrease 3 cm inboard Thickness(-4 kW ± 1 kW)~14.7 kW ±2.25 kWHigh EM loads (unacceptable for BM 1)Insufficient shielding12345Minimum acceptable gap for installationThe TF coil limit of 14kW can be increased by making less conservative assumptions in the calculations, by reducing the plasma pulse rate, by increasing the helium flow, and by reducing the cryoplant operating temperature. Slide11

The 15 MA, Q=10 reference plasma scenario has been re-

analyzed to check its potential performance with a central solenoid using the best conductor tested – main elements of the new scenario:

edesigned

plasma magnetization and initiation (see below)

fast (50 s) current ramp-up to 15 MA with heating during the current ramp to reduce l

and save fluxTwo scenarios of plasma initiation were designed with the TRANSMAK code:max(Ics)=37kA, max(Bcs)=12T  D(IM) = 17%max(Ics)=34kA, max(Bcs)=11T  D(IM) = 30%Reduction of the magnetic flux at the CS initial magnetization (IM) relative to the nominal scenario of plasma initiation is respectively:Δ(IM) ≈ -6.6Wb for D(IM) = 17% Δ(IM) ≈ -14.4Wb for D(IM) = 30%New Plasma Scenarios (1/4)Slide12

New Plasma Scenarios (2/4)

Based on extended test results from CSJA2, new plasma scenarios are being investigated.

The most conservative one offers a dramatic reduction in maximum loads, but plasma burn duration is limited to 265 s

Initial Magnetization (IM): 375

/m (70% of 535

/m) for all coilsEnd of Flattop: 375 kN/m (70% of 535 kN/m) for CS1The best leg of CSJA2 may be able to sustain 30,000 plasma pulses of this kind.Slide13

New Plasma Scenarios (3/4)

A plasma burn duration of 300 s can be achieved by relying on a slightly higher Lorentz load at initial magnetization (IM)

IM: 445

/m (83% of 535

/m) for all coils

End of Flattop: 375 kN/m (70% of 535 kN/m) for CS1 The number of plasma pulses of this kind that the best leg of CSJA2 can sustain will have to be investigated.Slide14

New Plasma Scenarios (4/4)

Compared

to the standard scenario where the maximum load is reached twice per pulse, in this new scenario it is only reached once per pulse.

 This should enable a minimum of 20,000 to 40,000 pulses, depending on the extrapolation method (not taking into account that the Lorentz load is only 83% of the one applied during the EM cycling of CSJA2).Slide15

Proposed Revised ITER Schedule

May be revised by STAC, MAC, and ITER Council Slide16

Noise Expected in dZ/dt

Measurements

Knowledge of low frequency plasma noise expected in ITER in

measurements is important for analysis of conductor heating and for design of controllers.According to analysis of JET (19 shots) and ASDEX-U (2 shots) experiments performed by CREATE, there is no dependence of the level of noise on plasma current and vertical instability growth rate. The noise expected in ITER in the frequency range from 0 to 1kHz has uniform spectrum with RMS value 0.20.4m/s in L-mode plasmas and 0.20.6m/s in H-mode plasmas.The scaling for noise used in ITER design needs to be confirmed on more wider experimental basis. Could this issue be studied in a relatively short time scale by members of the IOS group?Slide17

How fast can I

p be ramped up and the plasma become diverted with a high Z divertor? Over what density range? With what Zeff?

Is the

q95 space for early diverted plasmas similar to that for limited plasmas above?Need experimental program to assess these start-up issues for ITEREarly Diverted Start-up with a High Z DivertorSnipes, et al, Nucl Fus 28 (1988) 1085Operational Space in li vs q(a) Limited Plasmas in JETSlide18

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