EngineeringEngineering DesignDesign EvolutionEvolution ofof thethe JTJT --60SA60SA ProjectProject P. Barabaschi, Y. Kamada, S. Ishida for the JT-60SA Integrated Project Team EU: F4E-CEA-ENEA-CNR/RFX-KIT-CRPP-CIEMAT-SCKCEN JA: JAEA 1 JTJT --60SA60SA ObjectivesObjectives •A combined project of the ITER Satellite Tokamak Program of JA-EU (Broader Approach) and National Centralized Tokamak Program in Japan. •Contribute to the early realization of fusion energy by its exploitation to support the exploitation of ITER and research towards DEMO. ITER DEMO Complement Support ITER ITER towards DEMO JT-60SA 2 TheThe NewNew LoadLoad AssemblyAssembly • JT60-U: Copper Coils (1600 T), Ip=4MA, Vp=80m 3 • JT60-SA: SC Coils (400 T), Ip=5.5MA, Vp=135m 3 JTJTJT-JT ---60U60U JTJTJT-JT ---60SA60SA JT-60SA(A ≥2.5,Ip=5.5 MA) ITER (A=3.1,15 MA) 3.0m 6.2m ~2.5m ~4m 1.8m KSTAR (A=3.6, 2 MA) 1.7m EAST (A=4.25,1 MA) 1.1m 3 SST-1 (A=5.5, 0.22 MA) 3 HighHigh BetaBeta andand LongLong PulsePulse • JT-60SA is a fully superconducting tokamak capable of confining break- max even equivalent class high-temperature deuterium plasmas ( Ip =5.5 MA ) lasting for a duration ( typically 100s ) longer than the timescales characterizing the key plasma processes, such as current diffusion and particle recycling. • JT-60SA should pursue full non-inductive steady-state operations with high βN (> no-wall ideal MHD stability limits). 4 4 PlasmaPlasma ShapingShaping • JT-60SA will explore the plasma configuration optimization for ITER and DEMO with a wide range of the plasma shape including the shape of ITER , with the capability to produce both single and double null configurations. 5 5 Ip=5.5MA, Lower Single Null Ip=5.5MA, Double Null Ip=4.6 MA ITER like PhasedPhased ResearchResearch PlanPlan • Exploitation within the BA period will aim at the initial research phase: - HH operation for plasma full commissioning - DD operation for identification of the issues in preparation for full DD operation • Principles of “Joint Exploitation ” later phases agreed between EU and JA • Detailed “Research Plan ” jointly prepared Annual Expected Remote Max Phase Neutron Divertor P-NB N-NB ECRF Power x Time Duration Handling Power Limit H 1.5MW Initial phase I 1-2 y - LSN 10MW x100s 23MW Research partial + NB: 20MW x 100s Phase phase II 2-3y D 4E19 R&D monoblock 1.5MW 33MW Perp. x5s 30MW x 60s 13MW duty = 1/30 D phase I 2-3y 4E20 10MW Integrated LSN ECRF: 100s Research full- Tang. 37MW Phase D monoblock 7MW phase II >2y 1E21 7MW Use Extended Research >5y D 1.5E21 DN 24MW 41MW 41MW x 100s 6 Phase BaselineBaseline ScheduleSchedule -Start of Tokamak Assembly : Early 2012 -Completion of Tokamak Assembly : October 2015 -First Plasma : Mid 2016. 7 Device re -baselining • In late 2007, cost concerns prompted the Parties to request a re-design of the device. • Several ways to reduce costs were found in “old” design: • Issues found: Maximum field in TF conductor rather large for cost effective [email protected] design (Operation point : 6.5T at 5K, with 1K temperature margin). Conductor hot spot temp was unnecessarily low Structures rather heavy and complex to fabricate – multiple coil types Nuclear heating too conservatively estimated … • Solution: Reduce TF field, decrease SC strands volume (segregation), decrease Cu section Optimise structural design Recover plasma performance lost by field reduction by plasma volume increase made possible by reduction of magnet size Rationalise requirements and ports • In parallel some other problems were addressed: Seismic Loads to be managed by supports Peak TF Ripple in Plasma to be reduced to 0.5% Inductive flux for plasma operation to be increased to reach 100s flattop 8 DesignDesign atat >6T>6T costlycostly forfor NbTiNbTi (when(when Tcs~6K)Tcs~6K) T=6K T=5K 9 Aspect Ratio Optimised • τ R/a is the real only free parameter in the design of a Tokamak for a given nT • Trade-off between volume and power density • R/a determines important engineering factors Access to In-Vessel Components Wall power density Field and technology of magnets Mechanical loads Controllability of plasma shape • Optimum A is largely a function of technology, machine size, and scaling laws The Toroidal Field , and the density increase with Aspect Ratio The Plasma volume the Plasma Current, and τE decrease with Aspect Ratio 10 MainMain ResultsResults ofof rere --DesignDesign onon TFTF MagnetMagnet 2007 Design CDR NEW 2007 IDR 2008 TF Total TF Energy [GJ] 1.51 1.06 TF coils # 18 TF Tension [MN] 6.80 4.70 Number of turns in 1 coil 90 72 Peak Field [T] 6.43 5.65 Total length of conductor [km] 30.0 24.4 Total Structure Mass [ton] ~650 ~280 Strand type NbTi Conductor current [kA] 25.3 25.7 Cable space dimensions [mm] 25.1x25.1 18x22 N SC Strands 720 324 N Cu Strands - 162 Tmarg (after burn) [K] ~1.1 ~1.4 SC Strand mass in windings of 18 New Design 92 34 coils [ton] Segregated copper mass in 18 coils [ton] - 14 11 MainMain ResultsResults ofof rere --DesignDesign Additional Design Changes: •Cryoplant : heat load re -assessed based on new operation scenarios with reduced neutron yield and reduction of magnet cold structure. From 16kW to ~10kW and much improved dynamics •Cryostat : Single Wall with simplified geometry •Vacuum Vessel : Better distribute VV ports to provide a simpler out of plane support to the TF magnet structure. Reduction of shells •PF system : •Balance the distribution of turns in the EF system, •6 Coils (Vs 7), •Broader betap -li range, •28% less conductor •4 Independent CS coils (Vs 3) •TF Ripple Lowered: with Ferritic Insert will be <0.5% •Inductive Flux Increased: to ensure 100s flattop 12 MachineMachine ParametersParameters • After successful completion of the re-baselining in late 2008, the JT-60SA project was launched with the new design with the following parameters. Cryostat Basic machine parameters P-NBI P-NBI Plasma Current 5.5 MA Toroidal Field, Bt 2.25 T Major Radius, Rp 2.96 ECH Minor Radius, a 1.18 κ Elongation, X 1.95 δ Triangularity, X 0.53 N-NBI Aspect Ratio, A 2.5 Shape Parameter, S 6.7 Safety Factor, q95 ~3 Flattop Duration 100 s Heating & CD Power 41 MW N-NBI 10 MW P-NBI 24 MW ECRF 7 MW ２ Divertor wall load 15 MW/m 13 13 HeatingHeating andand CDCD SystemsSystems Variety of heating/current-drive/ momentum-input combinations NB: 34MWx100s Positive-ion-source NB 85keV 12units x 2MW=24MW COx2u, 4MW CTRx2u, 4MW Perpx8u, 16MW Negative-ion-source NB 500keV, 10MW for off-axis NBCD ECRF: 110GHz, 7MW x 100s 9 Gyrotrons, 4 Launchers with movable mirror 14 14 MagnetMagnet • All SC Magnet Nb3Sn for CS NbTi for TF, EF • 18 TF Coils • 6 EF Coils • 4 CS independent modules 15 ConductorsConductors Coil TF CS Type of strands NbTi Nb 3Sn Operating current (kA) 25.7 20 Nominal peak field (T) 5.65 ~9 Operating temperature (K) <5K <5.1K Number of SC strands/Cu strands 324 / 162 216 / 108 TFC conductor Local void fraction (%) 32 34 Cable dimensions (mm) 18.0 x 22.0 Φ21.0 Central hole (id x od) (mm) - 7 x 9 Conductor ext. dimensions (mm) 22.0 x 26.0 27.9 x 27.9 Conductor type EF-H EF-L No. of coils EF3, 4 EF1, 2, 5, 6 CS conductor Type of strand NbTi ← Operating current (kA) 20.0 ← Nominal peak field (T) 6.2 4.8 Operating temperature (K) 5.0 4.8 Number of SC/Cu strands 450 / 0 216 / 108 Local void fraction (%) 34 34 Cable dimensions (mm) 21.8 19.1 Central hole (id x od) (mm) 7 x 9 ← Conductor ex. dimensions (mm) 27.7 25.0 EF-L&H conductor16 16 TFTF MagnetMagnet featuresfeatures TF winding pack Connections area • Cable in Conduit Conductor , 72 turns, 25.7kA each • 6 double pancakes, 6 turns/pancake. Helium inlets in OIS high field side – joints in external low field side EF1 hanging • Windings enclosed in Steel Casings support arm • Steel casings supported to ground vertically and toroidally - connected in inboard curved regions by “Inner Intercoil Structure” • Steel casings guided toroidally by “Outer Intercoil Structure” to support out of plane loads. EF support pedestals Gravity support Reinforcement ribs 17 ViewView ofof MagnetMagnet -- assemblyassembly 18 TFCTFC ColdCold TestsTests • All TFC will be cold tested at full current before shipping to Japan • Test Facility will be in CEA-Saclay • PA prepared with test facility specifications and cold testing specifications HV Tests Leak Tests Flow, Pressure Drop Dimensional Stability during and after cooldown Resistance, Joints Tmargin, Quench tests (2 coils) • Cryostat and jigs being fabricated. • Cryostat to be delivered in Saclay in first half 2011 19 PowerPower SuppliesSupplies • Largely a full new set of Power Supplies compatible with long pulse operation have been designed and will be procured. These will include: • TFC, grouped in 3 units of 6 coils 6 pulse unidirectional, 26kA, 80V 3 Fast Discharge QPC Units (1.5KV to ground) • PFC, each coil with: 12 pulse, 20kA, ~1KV Booster (old units) or new Switching Network Unit Fast Discharge QPC Unit • In-vessel Coils • QPC Units: Under final tendering phase • SCM-PS: Technical Specs completed, Procurement Arrangement in final stage 20 VacuumVacuum VesselVessel • Double Walled • 18mm+18mm • Boronised Water interspace (~160mm) • 200C Baking • Procurement started, fabrication tests underway 21 MHDMHD ControlControl inin --vesselvessel componentscomponents ErrorError FieldField CorrectionCorrection CoilCoil (EFCC)(EFCC) ••toroidaltoroidal 66 xx poloidalpoloidal 22 coilscoils (TBD)(TBD) ••30kAT30kAT (TBD)(TBD) ••frequencyfrequency ~100Hz~100Hz (TBD)(TBD) ••RMPRMP forfor ELMELM controlcontrol FastFast PositionPosition ControlControl CoilCoil (FPCC)(FPCC) ••upperupper andand lowerlower coilscoils ••120kATurn120kATurn ••timetime responseresponse <10ms<10ms ••VDEVDE RWMRWM controlcontrol CoilCoil (RWMC)(RWMC) ••toroidaltoroidal 66 xx poloidalpoloidal 33 coilscoils (TBD)(TBD) ••20kAT20kAT (TBD)(TBD) StabilizingStabilizing PlatePlate ••SUS316LSUS316L ••DoubleDouble ShellShell 22 ••VDEVDE & & RWMRWM 22 CryostatCryostat • Originally (2007): spherical double walled with concrete shielding.