Diapositive 1Toroidal Field coils tests in the
Cold Test Facility
W. Abdel Maksoud
TFC tests in the Cold Test Facility
The JT-60 SA TF coils Cold Test Facility main goals are : - Mitigate the manufacturing risks by testing the coils in nominal conditions of temperature
(5 K) and current (25.7 kA) - Check a certain number of performances of the TF coils : DC/AC insulation, cooling down
characterization, RRR of the conductor, pressure drop in the winding pack, etc. - Measure the temperature margin of the TF coils against a quench
MT25 – Amsterdam - 28/08/2017 3W. Abdel Maksoud
Tesing progress
Coils integrated in the Tokamak: 9?
- Wed-Af-Po3.02 : P. Decool, “Completion of the French JT-60SA Toroïdal Field Magnet Contribution” - Mon-Af-Or4 : G.M. Polli, “Completion of ENEA’s procurement for 9 TF coils of JT-60SA tokamak“
MT25 – Amsterdam - 28/08/2017 4W. Abdel Maksoud
Warm tests
TESTS RESULTS SUMMARY
Visual checks - Minor: marks and scratches on the casing surface - Major: holes on casing straight leg corresponding to weld defects
created during the electron beam-welding phase repaired or to be repaired by WT
Temperature sensors checks - Major: non working sensor dismounted and repaired by CEA
DC insulation at 3 kV - Major: insulation fault at the soldering point of the terminal voltage
taps of TFC01 repaired by ASG - Major: insulation fault on TFC08 under investigation
Expected values TFC10 TFC11 TFC01 TFC12 TFC03 TFC13 TFC14 TFC04 TFC05 TFC15 TFC06 TFC16 TFC07 TFC08
Visual checks OK/NOK
DC insulation at 3 kV > 0.5 G
Leak test at 20 bars < 10E-8 Pa.m3/s
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Cooling down
Cooling down duration - Since TFC12 (4th coil tested) a nominal cooling down duration of 7-8 days has been achieved by CTF
for all coils
Pollution level during cooling down - From TFC10 to TFC13 (except TFC12)
pollution clogging's has been observed below 200 K. Between 1 and 3 evacuations has been made each time to clean the coil and be able to continue the cooling down
- GE visually observed oil traces in WT casing tubes of TFC14 and applied since then a cleaning procedure with Methyl Ethyl Cetone. No pollution clogging observed in CTF for TFC14, 15 and 16.
- Low level of pollution for ASG coils TFC04, TFC06 and TFC07 but very high for TFC05. Same cleaning procedure for all coils random level of pollution
0
1
2
3
4
5
6
7
8
9
Pressure drop (bar) due to pollution clogging at 170 K before evacuation
MT25 – Amsterdam - 28/08/2017 6W. Abdel Maksoud
Tests at 5 K (no current)
TESTS RESULTS SUMMARY
DC insulation at 3 kV - TFC01 & TFC08 DC faults same as 300 K - Major: insulation fault during the DC test of TFC07 at 5 K current tests cancelled and postponed to
after investigations and repair. Cooling down induced a crack in the insulation of the joints area creating a short cut with the ground conductive paint repaired by ASG waiting for 2nd campaign
As the 3 DC tests faults were visible first under vacuum and not air, DC tests in vacuum were added to the testing procedure beginning from TFC07
Expected values TFC10 TFC11 TFC01 TFC12 TFC03 TFC13 TFC14 TFC04 TFC05 TFC15 TFC06 TFC16 TFC07 TFC08
RRR > 100
DC insulation at 3 kV > 0.5 G
AC insulation (4 kHz, 0.5 kV, 1.5 s) 85 ± 15 %
Pressure drop (24 g/s, 4 bar, 5 K) 600 mbar ± 15 %
ΔT = Tout - Tin < 0.4 K
MT25 – Amsterdam - 28/08/2017 7W. Abdel Maksoud
Tests at 5 K (no current)
TESTS RESULTS SUMMARY
ΔT inlet-outlet value - Between 0.6 K and 0.9 K for all the coils due to a low cooling efficiency of the casing pipes inducing
40% of heat loads transfer to the winding should be within specification in Tokamak operation
Expected values TFC10 TFC11 TFC01 TFC12 TFC03 TFC13 TFC14 TFC04 TFC05 TFC15 TFC06 TFC16 TFC07 TFC08
RRR > 100
DC insulation at 3 kV > 0.5 G
AC insulation (4 kHz, 0.5 kV, 1.5 s) 85 ± 15 %
Pressure drop (24 g/s, 4 bar, 5 K) 600 mbar ± 15 %
ΔT = Tout - Tin < 0.4 K
0.4
0.5
0.6
0.7
0.8
0.9
1
Tests at 5 K and 25.7 kA
QUENCH TEMPERATURE TESTS RESULTS
- Due to the too high inlet-outlet ΔT, a dynamic procedure for Tquench measurement has been implemented instead of the static one
- For all the tested coils, the measured quench temperature is between 7.44 K and 7.52 K. These values are in agreement with the expected values computed thanks to the Tcs measurements made on the TF coils conductor and well above the minimum required value in the Tokamak (> 7.3 K)
MT25 – Amsterdam - 28/08/2017 9W. Abdel Maksoud
Tests at 5 K and 25.7 kA
QUENCH INITIATION
*Daniel Ciazynski *Valerio Tomarchio / Yawei Huang
57 % of quench initiated on side pancakes VS 29 % on central pancakes
Quench location
Inlet temperature
DP type
TFC10_2 DP1 - Side
TFC07 TBD TBD TBD
- Tue-Af-Po2.03 : D. Ciazynski, “analysis of early quench development in jt-60sa toroidal field coils tested in the cold test facility”
MT25 – Amsterdam - 28/08/2017 10W. Abdel Maksoud
Tests at 5 K and 25.7 kA
QUENCH PROPAGATION
Understanding the complex experimental physical behavior of the JT-60SA TF coils quench and modelling it is an important step in quench understanding that could be useful for JT-60SA operation and the protection and stability designs of ITER and DEMO.
- Thu-Af-Po4.02 : Y. Huang, “Numerical modelling of the quench propagation phase in the JT-60SA TF coils tested in CTF” - Thu-Af-Po4.02 : S. Nicollet, “parametric analyses of jt-60sa tf coil in cold test facility with supermagnet code“ - Tue-Af-Po2.03 : F. Bonne, “Dynamical Cryodistribution Model of the JT-60SA Toroidal Field Coil in Cold Test Facility”
MT25 – Amsterdam - 28/08/2017 11W. Abdel Maksoud
Tests at 5 K and 25.7 kA
INTER PANCAKE JOINT MEASUREMENTS
- All the inter pancake joint values are well within the specifications : < 10 n for the total value and < 5 n for the highest one
0.96 1.35 1.13 0.7 1.43
0.74 1.3 1.57 1.23 1.15 0.88 1.04 1.36
2.98 3.53 3.79
4.76
TFC10 TFC11 TFC01 TFC12 TFC03 TFC13 TFC14 TFC04 TFC05 TFC15 TFC06 TFC16 TFC07 TFC08
DPs interjoint resistance (n)
Conclusion
The JT-60 SA TF coils cold tests allowed to :
- Successfully cool down and test 13 JT-60SA TF coils under nominal conditions of temperature (5 K) and current (25.7 kA)
- Validate major performances of the TFCs like quenching temperature (between 7.44 K and 7.52 K) and joint resistances ( < 2 n)
- Find and solve or repair a certain number of non-conformities that could have caused major problems during the Tokamak operation like:
- Identify pollution clogging inside the coils during cooling down and find a procedure to clean the coils and proceed the cooling down
- Identify DC faults on 3 coils: 2 have been repaired, the 3rd is under investigation and one will be re-cold tested after repair
- Better understand and model the quench behavior of the coils (sometimes unexpected) through deep scientific experimental analysis and several modelling studies
13 TFCs tested with success 5 coils left!
MT25 – Amsterdam - 28/08/2017 13W. Abdel Maksoud
Thank you for your attention