TF System Quench analyses in operation condition

Transcription

1 Agenzia Nazionale per le Nuove Tecnologie, l Energia e lo Sviluppo Economico Sostenibile RICERCA DI SISTEMA ELETTRICO TF System Quench analyses in operation condition U. Besi-Vetrella, G.M. Polli, contributors: L. Zani(F4E), B. Lacroix (CEA) Report RdS/2011/ 391

2 TF SYSTEM QUENCH ANALYSES IN OPERATION CONDITION U. Besi-Vetrella, G.M. Polli (ENEA) Contributors: L. Zani(F4E), B. Lacroix (CEA) Novembre 2011 Report Ricerca di Sistema Elettrico Accordo di Programma Ministero dello Sviluppo Economico ENEA Area: Governo, gestione e sviluppo del sistema elettrico nazionale Progetto: Fusione nucleare: Attività di fisica e tecnologia della fusione complementari ad ITER, denominate Broader Approach Responsabile Progetto: Aldo Pizzuto, ENEA

3 UTFUS TF System Quench analyses in operation condition RT-JT60SA-012 Pag 1 di 15 Rev. 0 TF SYSTEM QUENCH ANALYSES IN OPERATION CONDITION Rev. 0 30/11/2011 List of Contributors: L. Zani (F4E) B. Lacroix (CEA) 0 30/11/2011 U. Besi-Vetrella G.M. Polli Rev. Date Author Reviewer Approver

4 TF system quenchanalyses U. BESI-VETRELLA (ENEA), B. LACROIX (CEA), G. M. POLLI (ENEA), L. ZANI (F4E) 1- Introduction 2- Reference configuration 3- Parametric analyses 4- Conclusion & perspectives DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI 1/13

5 1- Introduction Recent investigations on the impact of some design changes regarding components linked to the TF magnets system (TF strand, Power Supplies) Need of finalization for the protection system features New modelisation works were launched both regarding thermohydraulics approach (Gandalf) or with more simple thermal approach (xls solver) The results presented here aim at setting the main parameters for protection circuit and show their robustness in terms of reliability for magnet protection purpose DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI 2/13

6 2- Reference configuration Simulation of a quench with the GANDALF code: on the CW median conductor in operating conditions (Iop = A) with the heat perturbation deposited in the middle of the Bmax zone (x = 12.5 m) Main hypotheses: Model limited to the 114 m conductor (cryolines/feeders not represented) Updated friction factor correlation according to pressure drop measurements Updated strand design (A Cu reduced of 5% >> CuNi barrier change), RRR=100 DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI 3/13

7 2- Reference configuration Initial conditions (magnetic field & temperature distributions) correspond to the End Of Burn for the 100 s burn scenario with NY = n/s B (T) Magnetic field before quench initiation (EOB) Bmax = 5.55 T on perturbated zone T (K) Tconductor & Tcs before quench initiation (EOB) Tma = 1.6 K on perturbated zone Tcond Tcs x (m) Calculation baseline configuration: DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI 4/ x (m) 1 m heat deposition on equatorial plane (from 12 to 13 m) during 1 s Reference MQE (RMQE) = 132 W ~ 791 mj/cc Quench triggered with 2*RMQE Reference features for protection circuit : Voltage detection threshold = 0.5 V Tdelay (after detection) = 1 s highly conservative approach with respect to PID conditions, but referring to real exploitation conditions (e.g. Tore Supra)

8 2- Reference configuration Case # V_detect[V] T_delay[s] RRR heated length[m] Mdot[g/s] T_duration [s] P_perturb MQE [W/m] MQE [mj/cm^3] Ref *MQE 2*132 2* ,50E+06 1,50 2,70E+04 Tcond (K) Tcond at x = 12.5 m Pressure at x = 12.5 m 2,00E+06 1,50E+06 1,00E+06 5,00E+05 Pressure [Pa] Volatge (V) 1,00 0,50 Voltage Current 2,60E+04 2,50E+04 2,40E+04 2,30E+04 2,20E+04 2,10E+04 Current [A] 0 0,00E+00 0,00 10,00 20,00 30,00 40,00 50,00 time (s) Pressure < 25 bar (value considered for mechanical analyses) the conductor temperature < 130 K (upper classical limit ~150 K) 0,00 2,00E+04 0,00 1,00 2,00 3,00 4,00 5,00 Voltage detection threshold (0.5 V) time (s) Delay time after detection (1 s) DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI 5/13

9 2- Reference configuration Case # V_detect[V] T_delay[s] RRR heated length[m] Mdot[g/s] T_duration [s] P_perturb MQE [W/m] MQE [mj/cm^3] Ref *MQE 2*132 2*791 Tmeperature (K) 1,40E+02 1,20E+02 1,00E+02 8,00E+01 6,00E+01 4,00E+01 2,00E+01 Temp. vs. 40 s REF. case 0,00E+00 0,00 50,00 100,00 Distance from inlet (m) Length (m) 35,00 30,00 25,00 20,00 15,00 10,00 5,00 Normal length vs. time REF. case 0,00 0,00 10,00 20,00 30,00 40,00 50,00 time (s) The extension of the normal length keeps below 40 m during the period considered for simulation Current (A) Current vs. time 0 0,00 20,00 40,00 time (s) At 40 s I ~ 1000 A DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI 6/13

10 3- Parametric analysis: overview Case RRR T_delay [s] A_Cu [mm 2 ] P_perturb [W/m] Length [m] V_detect [V] Ref * RRR T_delay A_Cu strand MQE *132 - Length V_detection DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI 7/13

11 3- Parametric analysis Sensitivity to detection voltage Voltage (V) Tmax (K) Pmax (bar) at x = 12.5m Tcond max x=12.5m Tcond (K) P (bar) Reference Strong impact of detection voltage on Temperature 0 0,2 0,4 0,6 0,8 1 1,2 Detection Voltage (V) Sensitivity to perturbation length Perturbation length (m) Tmax (K) Pmax (bar) at x = 12.5m Perturbation Power (W/m) ,05 157,2 17,9 2*524 0,2 149,5 18,5 2*196 Tcond (K) Tcond max x=12.5m 20 P (bar) Reference ,1 2* ,2 21,5 2*112 The lower heated length, the higher Tcond, but acceptable Triggering zone length (m) DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI 8/13

12 3- Parametric analysis 6 Shifting the heated zone in the Bmax area low impact B (T) Heated zone shifted upstream or downstream Heated zone position Tmax (K) Pmax (bar) at x = 12.5m upstream Center (ref.) downstream x (m) Influence of the perturbation energy 1,E+05 Perturbation & Joule volumic energy P_perturb 2 MQE = 2 * 132 W/m 10 MQE = 10 * 132 W/m Tmax (K) Pmax (bar) at x = 12.5m E (mj/cc) 8,E+04 6,E+04 4,E+04 2,E+04 Ejoule - 10 RMQE Ejoule - 2 RMQE Eperturb - 10 RMQE Eperturb - 2 RMQE Joule heating dominates limited impact of perturbation energy 0,E time (s) DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI 9/13

13 3- Parametric analysis Sensitivity to delay time after quench detection 150,00 140,00 Tcond max x=12.5 m 24,5 24 Reference Delay time (s) Tmax (K) at x = 12.5m Pmax (bar) at x = 12.5m Tcond[K] 130,00 120,00 110,00 23,5 23 Pressure [bar] ,00 22,5 90,00 0 0,5 1 1,5 2 Delay time [s] 22 The longer delay time, the higher Tcond, but acceptable DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI 10/13

14 3- Parametric analysis Sensitivity to parameters relevant of manufacturing tolerances RRR Tmax (K) Pmax (bar) at x = 12.5m Tcond [K] Tco max at t = 40 s Pmax at x=12.5 m Pressure [bar] RRR The lower the RRR time, the higher Tcond, but acceptable Pressure also increases even if not dramatically critical DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI 11/13

15 3- Parametric analysis Conservative model cross-check used for design in a straightforward approach (see presentation TCM ). Working hypotheses : - reference scenario same as Gandalf, with reaching V detect immediatly - RRR taken as minimum in TF strand specifications value of 80 T MAX ~ 263 K Gandalf cross check - in similar conditions (no He) T MAX ~ 25 K good consistency, still under investigations Mitigation : RRR is in average higher than specifications - from Cu and NbTi production the minimum "effective RRR" ~ 100 T MAX ~ 250 K - in similar conditions (no He) in Gandalf T MAX + 25 K still under investigations but good consistency, Remark : upper limit value commonly used is 250 K but the present situation is highly conservative (no Helium present in the cable) and this criterion is commonly considered for "dry magnets", which is not the case for JT-60SA. DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI 12/13

16 4- Conclusion & perspectives A reference configuration for TF magnet protection system was defined with : - a voltage detection threshold of 0.5 V - a delay after detection of 1 sec This configuration aims at enabling a good capacity to distinguish transient parasitic signals to real DC quench ones ("filter" by amplitude and frequency). The present analyses led with Gandalf showed that this reference configuration is robust, demonstrated as : - showing acceptable cable temperature (<130 K) and pressure (< 25 bar) increase for a quench scenario which is reasonably conservative. - being in a domain where the variations of central parameters (RRR, detection V, delay time or length quenched) do not imply a critical change in the temperature rise. Should this reference configuration features be agreed, it is then proposed that the PID is modified accordingly. Some further investigations are under consideration to consolidate the results before switching to the TF cold tests configuration. DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI

17 3- Parametric analysis Pressure [Pa] Sensitivity to parameters relevant of manufacturing tolerances Pressure distribution with RRR=130 2,00E+06 1,80E+06 t= 0.0 s 1,60E+06 t= 1.0 s 1,40E+06 t= 2.0 s 1,20E+06 t=10.0 s 1,00E+06 8,00E+05 6,00E+05 4,00E+05 2,00E+05 0,00E+00 0,00E+00 2,00E+01 4,00E+01 6,00E+01 8,00E+01 1,00E+02 1,20E+02 Distance [m] DRM13, Karlsruhe 5 December 2011 U. BESI-VETRELLA, B. LACROIX, G.M. POLLI, L. ZANI 14/13