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Assessment of fuel retention in JET : Contingency – 2 shifts on 6 th of february E. Tsitrone for J. Bucalossi and T. Loarer Motivation Previous results Pulse configuration. T inventory (g). Nb of ITER pulses. Motivation : tritium retention in ITER. ITER predictions :
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Assessment of fuel retention in JET : • Contingency – 2 shifts on 6th of february • E. Tsitrone for J. Bucalossi and T. Loarer • Motivation • Previous results • Pulse configuration
T inventory (g) Nb of ITER pulses Motivation : tritium retention in ITER • ITER predictions : • Codeposition dominates • T retention : 1 to 4 g of T per 400s pulse • ITER in vessel T inventory limit : 360 g of T 100 to 350 pulses Code validation : Underestimation of the JET DTE1 T retention by a factor 10-40 need for experimental data G. Federici, Workshop on In Vessel Tritium Inventory, JET, March 2003
Medium Gas Puff Shot 59197 16 s of flat top in H mode Ip = 1 MA, 6 MW of NBI Previous results : H mode long discharges at JET • Particle balance during shot : • Dynamic retention : 50 % of injected gas (TS) • Integrated particle balance : • Long term retention : 10 % of injected gas
Assessment of fuel retention in JET TFE C14 - Feb. 6th Early and Late SCs: J. Bucalossi/T. Loarer SLs: G. Matthews/M. Stamp • Aim: perform a gas balance with the maximum accuracy • Divertor Cryopump regeneration just before and just after the session (+ gas analysis) • no NBI (no LHCD) to avoid NBI Box (LHCD) pumping • no disruption • high D2 fuelling rate (in feedback control to avoid disruption) • maximum pulse rate • Calibration : gas injection w/o B field and w/o div cryopump (to calibrate pressure gauges) • dry run with gas puff (to check divertor pumping speed) • Scenario: 2MA/2.43T, 5-6MW ICRH, 42 MHz dipole, high density (90fr) • ref. pulse #61751… (POG/TTE_CLEANUP/1.3), Gas ~ 6 bar.l • combined with QMB available data for divertor configuration choice • (DOC L/Vertical/Corner/Horizontal target,4 pulse types ?) • 40 pulses at 6 bar.l/pulse ~ 240 bar.l (reasonable for PCD and GB)
22 JPN 61751 - Plasma Parameters Gas Injection x 10 4 2.5 RF (MW) 2 2 ne (1019m-3) 1.5 Electrons / s 0 1 NBI (MW) -2 0.5 Z Xp (m) -4 0 40 50 60 70 80 40 50 60 70 80 Ip (MA) P /P Pressure Measurements divertor vessel -2 10 200 150 -4 10 100 mbar -6 10 50 sub-div -8 0 10 40 50 60 70 80 40 50 60 70 80 vessel Typical scenario (from TTE clean-up)
23 JPN 61751 - Particle Balance x 10 3 N puff N 2.5 nbi N e N 2 div N exh N 1.5 wall electrons 1 0.5 0 JPN 61751 1 Retention -0.5 0.9 40 45 50 55 60 65 70 75 80 85 t (s) 0.8 @ t = 88.6 s 0.7 3 3 Injection : 599 Pa.m Exh. Div. : 205 Pa.m 0.6 3 3 Wall : 389 Pa.m Exh. Ves. : 4.34 Pa.m 0.5 0.4 0.3 0.2 0.1 0 56 57 58 59 60 61 62 63 64 65 66 t (s) Tentative particle balance (with 2001 calibrations) “Dynamic” D retention Feb 6th in-vessel fuel retention ~ (total gas input – PD Regen.)/total gas input