Presentation Transcript

1. DPG Meeting Dresden The optimized stellarator as a candidatefor a fusion power plant Thomas Klinger C. Beidler, J. Boscary, H.S. Bosch, A. Dinklage, P. Helander, H. MaaßbergT.S. Pedersen, T. Rummel, F. Schauer, L. Wegener, R. Wolf andthe Wendelstein 7-X team Max-Planck Institute for Plasma Physics, Greifswald DPG 2013
2. Outline ofthe talk Max-Planck Society Challenges Stellarators Wendelstein 7-X Research program Fusion power plant National funding via the Helmholtz Association Co-FundedbytheEuropean Commission DPG 2013
3. Challenges in fusionresearch nuclearfusionof D and T nuclearphysics well understood hightemperatureplasma inertialconfinement magneticconfinement temperatures > 10 keVOK densities > 1020 m-3 OK confinement > 10 s × 10 steadystateoperation O(s) superconductivityLHe tritiumbreeding wall materials 1D2 + 1T3 2He 4 (3.5 MeV) + 0 n1 (14.1 MeV) T. Klinger on Wendelstein 7-X 3
4. The classical stellarator Stellarator (1951 Spitzer)Stella = thestar„bringingthestar“ T. Klinger on Wendelstein 7-X 4
5. Physicsoptimisation sevenoptimisationcriteria highqualityofvacuummagneticsurfaces good finite equilibriumproperties @ < > = 5% good MHD stabilityproperties@ < > = 5% reducedneoclassicaltransport in 1/ -regime smallbootstrapcurrent in lmfp-regime goodcollisionless fast particleconfinement goodmodular coilfeasibility 3d computercodes vacuumfieldandcoils MHD equilibrium MHD linear stability neoclassicaltransport Monte Carlo testparticle edgeand divertor T. Klinger on Wendelstein 7-X 5
6. Facts andfigures fivemagneticfieldperiods modular non-planarcoils quasi-isodynamicequilibrium lowbootstrapcurrent<50 kA highiotaandlowshear flexible magneticfieldconfigurations 725 t masswith 425 t coldmass 70 superconductingNbTicoils 3 T magneticinduction on axis 254 portsof 120 different types 30 m3 plasmavolume 265 m2 in-vesselcomponents height 4.5m diameter 16 m 30 min plasmaoperation T. Klinger on Wendelstein 7-X 6
7. Major devicecomponents fiveroughlyidenticalmodules 254 ports cryostatvessel~ 500 openings accessdomesandinstrumentationplugins SC bus bar 3d-shapedplasmavessel He pipes 2500 in-vesselcomponents cryofeet machinebase 14 HTSCcurrentleads plasma 50 non-planar20 planar SC coils thermal insulationMLI and He gas cooledshield centralsupport ring T. Klinger on Wendelstein 7-X 7
8. The island divertor concept intersection of natural magnetic islands with target plates target plates plasma contour divertor units triangular plane triangular plane bean plane T. Klinger on Wendelstein 7-X 8
9. The in-vesselcomponents activelycooled wall elementsheatloadfrom 100kW/m2to 10MW/m2 tenwater-cooled divertor controlandsweepcoils 20m2targetelements CFC sealed on cooledCuCrZr ten cryo pumps 20m2 baffleelementsgraphiteclamped on CuCrZr 60m2 heatshieldsgraphitebolted on CuCrZrand 60m2steelpanels T. Klinger on Wendelstein 7-X 9
10. 6 Yearsof Magnet Manufacturing completedmagnetmodule14 non-planarand 4 planarcoils T. Klinger on Wendelstein 7-X 10
11. 10 Yearsof Device Assembly high-precisionjoiningtwomagnetmodules130 t deadweighteach T. Klinger on Wendelstein 7-X 11
12. Assemblystatusoverview all 5 modulesarecompletedand on themachinebase assemblyofthe 254 portsclosetocompletion all moduleseparation planes closed magnetsystemcompleted in-vesselassemblyworksstarted theprojectis on schedulesince > 5 y T. Klinger on Wendelstein 7-X 12
13. Presentviewoftheassemblysite T. Klinger on Wendelstein 7-X 13
14. A viewintothetorus hall 2014 T. Klinger on Wendelstein 7-X 14
15. Research needstowards DEMO verificationof stellarator optimizationpoints 1.-6.thephysicsis well understood; goalscanbereachedduringthefirstfewyearsofoperationincludinghigh- and fast particleconfinement highdensities, hightemperature, goodenergyconfinementenergyconfinement must beasgoodasfor a similarsizetokamakatlowcollisionality, high- andhigh-nT (integratedscenarios) densitycontrolwithcentralfuellingneoclassicalthermodiffusionleadstohollowdensityprofilescontrolledhighdensityoperationwithcentral pellet fuelling noimpurityaccumulationathighdensitiestheambipolarelectricfieldtendstobe negative radiationcollapse in ELM-free H-mode – HDH modeassolution? viable divertor performancehighdensity 21020 m-3operationwithsteady-state 10 MW/m3heatloadfulldensitycontrol, partial detachment, 90% radiated power fraction microwaveheatingofhighdensityplasmasdenseplasmaswith O2 andoverdenseplasmaswith OXB T. Klinger on Wendelstein 7-X 15
16. Neoclassicaltransport hollowdensityprofiles D2a>0outwardthermodiffusion theD‘sare larger fortheionsthanfortheelectrons (4) inwardErcausingimpurityaccumulation T. Klinger on Wendelstein 7-X 16
17. Wendelstein 7-AS HDH Mode (4) highdensity H-mode not well understood T. Klinger on Wendelstein 7-X 17 McCormick et al. PRL (2002)
18. Wendelstein 7-X Forecast Numericalsimulationspredictgoodproperties: neoclassicaltransportstronglyreduced good MHD stabilityandequilibriumproperties reducedfluxoftrapped 50 keVparticlesfromthecore * continuous pellet fuellingfordensityprofilecontrol divertor detachmentandhighrecycling well achievable divertor magneticlowbootstrapcurrentconfigurations * athigh <> nomajorissue was foundduringtheconstructionperiod T. Klinger on Wendelstein 7-X 18
19. Research plan – firstthoughts I developcrediblesteady-statescenarios 1st operationphase T=5-10s 8 MW ECRH 3.5 MW H+-NBI shutdown 2y controlledhighdensitydischarges divertor loadsand operationlimits divertor detachmentandhighrecycling confinementandstabilityproperties denseplasmaswith NBI and O2 impuritycontrolinvestigations end ofdevicecommissioning X2 ECCD foredgeiotacontrol initialimpuritytransportstudies high- plasmasand fast particleconfinement 1st NBI heatedplasmas 1st X2-heated plasmas T. Klinger on Wendelstein 7-X 19
20. Research plan – firstthoughts II high-power steadystateoperation 2nd operationphase T=30s … 30min 10 MW ECRH (steadystate) 7 MW H+-NBI 10 MW D+-NBI 5 MW ICRH HHF steady-state divertor controlledlong pulse discharges fullscenario integration HHF divertor loadsandoperationlimits densityandimpuritycontrol … long pulse full power X2 heatingand CD densityprofileshapingwithpellets end ofdevicecommissioning -limitexplorationand fast particlephysics long pulse full power O2 heating 1st NBI heatedplasmas 1st ICRH heatedplasmas 1st X2-heated plasmas T. Klinger on Wendelstein 7-X 20
21. A stellarator FPP * a few stellarator FPP design aspects highaspectratio (R/a > 10) relaxesnumeroustechnicalconstraints thecoilsarebasically 3d-shaped ITER TF coils (Nb3Sn 12 × 7.5 m) the divertor geometryfollows a helicalpath shapeof wall elementsisgivenbymagneticfieldtopology enoughspaceforblanketbetweenplasmasurfaceandcoilcasing (1.3 m) sufficiently large verticalports (4.3 × 2.2 m2) * Beidler et al., Coordinated Working Group Meeting (2012) T. Klinger on Wendelstein 7-X 21
22. A stellarator DEMO study Schauer et al., SOFT 2012 T. Klinger on Wendelstein 7-X 22
23. Conclusions The constructionof Wendelstein 7-X is still on track. The last threemajorworkpackageshavebeenlaunched. Technical challangesareahead. Therearemanylessonslearned. The Wendelstein 7-X research plan isunderdevelopment. The knowledebaseiscontinuouslyextended. A research plan will bedevelopedjointlywithourpartners. The majorgoalsare- relevant plasmaperformance -high power steady-stateoperation -fullscenariointegration The researchistargetedtowards a stellarator FPP. T. Klinger on Wendelstein 7-X 23