Transcript IEA_IA_AUG
Status of the ASDEX Upgrade Tokamak Programme Hartmut Zohm MPI für Plasmaphysik, EURATOM Association • Status of flywheel generator(s) • Midterm hardware extensions • planning for 2007/2008 campaign(s) • Status of ITPA joint experiments Joint Executive Committee session of IEA-IAs on Pol. Div Tokamaks and Large Tokamaks, Naka, Japan, May 21, 2007 Status of Generator EZ4 ASDEX Upgrade powered by 3 flywheel generators: • EZ2 (1450 MJ / 167 MVA) for toroidal field coils • EZ3 ( 500 MJ / 144 MVA) + EZ4 (650 MJ / 220 MVA) for poloidal field coils and auxiliary heating Accident in April 2006 led to severe damage on EZ4 • failure of control system – generator continued to run until out of oil • rotor touched stator – damage to stator windings, rotor shaft rotor - can be repaired stator - must be rebuilt Repair is possible at Siemens Dynamowerk Berlin • expensive and time consuming, projected delivery ~mid 2008 Midterm Hardware Extensions Midterm Hardware Extensions Will open unique possibilities for the EU Accompanying Programme Status of Tungsten Wall Project April 2007 Status of Tungsten Wall Project Full W-coverage in 2007: • all PFCs now W-coated Future AUG wall could be W or C: • depends on possible performance limitations • need qualified answer for ITER first • JET ‘ITER-like wall project’ may need direct experimental support) W-coated divertor tile with solid W Langmuir heads Extension of ASDEX Upgrade ECRH system Fast (50 ms)steerable launcher for real-time deposition control 2-frequency gyrotron (GYCOM, Russia) 105/140 GHz, 1 MW, 10 s (first of its kind – next will be 4-frequency) Internal Coils and Conducting Shell 3 poloidal sets (midplane outside) 4 toroidal sets Proposal is staged to allow several physics applications • 24 coils to generate up to n=4 error fields with different poloidal strucuture • with 1 power supply, n=1,2 and 4 is possible (fast track to ELM suppression) • with 12 power supplies, n=3 and rotating helical field studies can be done • together with conducting shell, n=1 RWM stabilisation experiments possible • further upgrade to 24 power supplies would enable multi-mode control Planning for 2007/2008 campaigns Programme Planning for 2007 Operation of ASDEX Upgrade without EZ4 possible at reduced parameters • limit to current/shaping capability, pulse length and heating power The tungsten wall programme in 2007 can be conducted • will require careful approach (power, pulse length) anyway ITER relevant plasma physics experiments will need EZ4 back in 2008 • need to go to small r* at low collisionality • demonstration of sophisticated feedback control needs longs pulses Programme Planning for 2007 A stepwise approach for the tungsten programme was agreed: 1.) study of compatibility of W-wall with ITER scenarii 2.) extension of parameter space to higher power/lower density 3.) ITER physics studies where emphasis is not on W (e.g. Improved Hmode) significant limitation to general ITER physics studies in 2007 (also impacting possibilities for ITPA joint experiments) Startup without boronisation… • Operation/investigation of W machine without (any) intrinsic low-Z radiator • Comparison of boronised / un-boronised machine: maybe able to proof of hypothesis on B influence • D retention ‚without‘ low-Z (C,B) contamination • Comparison of D pumping W wall / boronised W wall and H-D transition However, at the cost of higher (initial) O-concentration Together with reduced generator power, restart was somewhat slower …successfully accomplished this month! …successfully accomplished this month! …successfully accomplished this month! Low loop voltage startup Saves generator power …successfully accomplished this month! Radiated power is low (Prad/Ptot = 1/3) and stable …successfully accomplished this month! Managed to inject 3 MW (2.5 absorbed) of ECRH from 5 gyrotrons! Status of ITPA joint experiments Status of ITPA joint experiments No experiments since April 2006, but AUG staff participating in other joint experiments: • role of pedestal in improved H-mode (C. Maggi at DIII-D) • investigation of b-scaling of transport (L. Vermare at DIII-D) • size scaling of NTM stabilisation by ECCD (L. Urso at JT-60U) Highest priority in 2007 is on tungsten wall programme • ITPA experiments only within present boundary conditions In mid 2008, full performance experiments should be possible again • damaged generator should be back in operation • full W-wall is still a boundary condition that has to be observed