ITPA IOS Meeting October 18 21 2011 Kyoto Japan T A Casper D Campbell Y Gribov SH Kim T Oikawa A Polevoi JA Snipes A Winter and L Zabeo ITER ID: 156058
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Summary of ITER scenario work
ITPA IOS MeetingOctober 18 – 21, 2011Kyoto, Japan
T. A. Casper, D. Campbell, Y. Gribov, S.H. Kim*, T. Oikawa, A. Polevoi, J.A. Snipes, A. Winter, and L. Zabeo ITER Organization, Route de Vinon sur Verdon, 13115 St Paul Lez Durance, France*Monaco post doctoral program at ITERAcknowledgement: CORSICA supportR. Bulmer, L.L. LoDestro, W.H. Meyer, and L.D. Pearlstein, Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, CA USA 94550Slide2
Modeling development for ITER scenarios: 1D transport + 2D equilibrium only (does not include other modeling work at ITER)Scenario development that requires lots of parameter variation studies can and often is done with prescribed boundary evolution Controller development and evaluation of engineering constraints require free-boundary with coupling to external systems
Scenarios of interest:Full field scenarios at BT=5.3T in H-mode:Baseline inductive: IP=15MA, Q=10, Pfus=500MW, to 400s durationAdvanced inductive or hybrid: IP=12.5MA, Q=5, 1000s durationSteady-state: IP=9MA, Q=5, steady state – likely internal transport barrierLow-activation scenarios: DD at I
P=7.5MA and BT=2.65T (half IP, BT) Under development and of current interest for early experimentsNon-activation scenarios: H or He operations at reduced IP, BTNew interest for modeling to minimize CS coil demandsMHD evaluation for scenariosSlide3
Approaches leading to development of ITER scenariosInternal at the IOTo develop internal ideas quickly and to test conceptsBuild on and supplement work done outside the IORapid response to committees and engineering design crises
Provide data to external research efforts, e.g. equilibria, profiles, constraints, etc.Funded ITER tasksMajor efforts to scope out scenarios and/or design modifications – longer termContracts and must be competed among the DAs, a somewhat slow processVolunteer – many efforts in DA programs typically coordinated by ITPABenchmarking with experimental dataModel and code validationModeling scenarios and detailed physics aspects – a few recent examples:ISM coordinated effort in EU (Litaudon) – several codes and variety of topicsIndividual efforts in scenarios with both DINA(Russia) and TSC(US)Data sent for many physics studies: BOUT and ELITE edge stability, MHD evaluation, ECH study, RMP study, first wall evaluation, runaways, ripple loss, etc. etc. etc.Slide4
Recent ITER tasks and internal studies have advanced understanding of likely ITER performance: mostly CORSICA, DINA, and TSCCurrent modeling includes latest modifications to ITER systemscoil and first wall geometry (may change again)power systems and source design parameters
Increasing awareness of the divertor and first wallBaseline inductive modeling – successful scenarios within operating spaceKessel, C.E. et al Nucl. Fusion 49 (2009) 085034Casper, T. et al accepted Nuc. Fusion 51(2011) ; in Fusion Energy 2010 (Proc. 23rd Int. Conf. Daejeon, 2010) (Vienna: IAEA) CD-ROM file
ITR/P1-19 http://www-naweb.iaea.org/napc/physics/FEC/FEC2010/html/index.htmITER tasks and efforts at the IO advanced modes: advanced inductive (hybrid) and steady-state scenarios (Gormezano, C. et al Nucl. Fusion 47 (2007) S285-S336)Kessel, C.E. et al in Fusion Energy 2010 (Proc. 23rd Int. Conf. Daejeon, 2010) (Vienna: IAEA) CD-ROM file ITR/P1-22 and http://www-naweb.iaea.org/napc/physics/FEC/FEC2010/html/index.htmEU/F4E modeling effort currently in progress – results later today?IO modeling effort started for hybrid mode: Sun Hee Kim presentationSlide5
Voluntary efforts have contributed significantly to ITER scenario development understanding – for example, a recent STAC report:TOPICS-1B: N. Hayashi et al., Final
Report on the ITER Task Agreement C19TD26FJ ITER_D_48DP5Z, 24 February 2011.
CRONOS: J. Citrin et al., Nucl. Fusion 50 115007 (2010).Code-code comparison for steady-state scenariosMurakami, M. et al. Nucl.
Fus
.
51
103006 (2011).Slide6
CORSICA: Current emphasis for modeling at the IO is control of scenarios and development of the plasma control system (PCS)2D equilibrium + 1D transport predictive modeling code provides capability for controller simulations - applied to shape, vertical stability and profile control
Crotinger, J.A. et al LLNL Report UCRL-ID-126284,1997 NTIS #PB2005-102154Full free-boundary GS solutions with various transport models - control of the evolution of plasma shape, vertical position and kinetic profilesSimultaneously converges free-boundary equilibrium with transport at each time step – solutions always self-consistent Calculates sources each time step - needed for feedback control applications Monte-Carlo NBI with orbits and Toray-GA ECH/ECCD – previously used for DIII-D modeling and updated for ITER by Sun Hee KimICH and LH capability recently added by Sun Hee Kim
DCON for time-dependent MHD stability assessmentCoupled with simulink control environment - independently executing and connected with RPCs (Meyer, W. et al, IAEA-TM, San Francisco June 2011) Modular, customizable with interruptable work flows from interpretive scripting language interface – flexible and extensible environmentSlide7
Elements in place at ITER for a PCS simulator: ITER control methods, JCT2001 controller, CORSICA implementation
(b) Corsica realization of control simulator
Casper, T.A. et al, FED 83 (2008) 552-556(c) ITER shape and vertical position control (d) JCT2001 controllerSlide8
CORSICA (or any code, e.g. DINA, TSC) free-boundary capabilities are required for controller modeling and developmentCORSICA modes of operation (Casper, T.A. et al, FED 83 (2008) 552-556)
“backing-out”: fast, prescribed boundary evolution (no controller) with free-boundary evaluation at each time step to couple to external systemsFast scenario developmentMost engineering constraints evaluated, e.g. currents, forces, limitsProvides feed-forward waveforms for forward control“forward” : full free-boundary shape and vertical stability evolution with controller – must run with dt ~ vertical growth time so lots of time-steps required“hybrid”: free-boundary shape from controller in simulink with vertical stability internal to CORSICA – a new development done for speed in long pulse control simulationsCoupling to simulink provides a mechanism to test controllers (shape, vertical stability, and profile) during development
JTC2001 controller +VS1,VS3 both in simulink and internal to CORSICAInterpretive interface with interrupts provides a mechanism for simulating event handlingSlide9
CORSICA feedback-controlled evolution for baseline inductive case: IP=15MA, Q=10, 400s duration burn and Pfus=500MW JCT-2001+VS1 controlled shape and vertical position, typically ~15,000 converged free-boundary solutions (700s discharge)
Performance results (a)Coil currents (b,c) and forces (g) within operational limitsController voltage demands for vertical stability (d) and shape (e,f)
(g)Slide10
Time-dependent evaluation (B,I)-limits and forces on coils
New diagnostic: UFC = utilization factor for superconducting coils – moved from equilibrium design to time-dependent
* Simulation from fast current ramp with 17%reduction in I*B ~ different initial magnetization state* Power ramp to control power to divertorSlide11
Summary/Future: the tools are in place and we are simulating a variety of controller aspects for ITERController development - simulations will support these effortsNew controllers have been proposed for improving ITER performanceThe Plasma Control System (PCS) conceptual design in progress Shape and vertical position
Significant efforts have been done for the baseline 15MA caseThis needs to be extended to the alternative scenariosAdvanced inductive (hybrid) is being worked onThe Steady-state control will be doneNon- and low-activation scenario are being defined and developedKinetic control efforts for performanceFeed-back control of q (current profile)Temperature and stored energy controlBurn controlStabilization of islandsEvent simulation, database and display testingSlide12
Additional concerns/emphasis for scenario modeling with regards to experimentsMore experimental validation of codes used for ITER scenario analysisLots has been done to date, keep going
Concepts that need to be integrated into scenarios, e.g. divertor and stabilityEffort to benchmark profile control between simulations and experimentsSpecific studies of current ramp-up/ ramp-down scenarios under ITER-relevant conditions (i.e. potentially with a tungsten divertor) Compatibility with tungsten divertorNow using power ramp (5-20MW) during current ramp Characterization of MHD during the current ramp-up in X-pointconfigurations
Fast, heated current ramp-up after X-point formationStability boundary lurking somewhereNon-activation or low activation DD scenariosIP/2 and BT/2 with ECHFull BT at reduced IP ~ 10 or 12MACS coil limitations for “reduced” operation