The ITER toroidal field model coil project

218 A. Ulbricht et al. / Fusion Engineering and Design 73 (2005) 189–327
control dewar (B250). With this method, the coils were
kept cold, the control dewar (B250) was filled, and the
running time of the He pumps was reduced by about
60%. An unattended operation during nights and weekends
was possible and the change from standby mode
to the operation mode with the full mass flow rate was
done every morning in about 2 h (Fig. 4.19). The mass
Fig. 4.15. Heat load of the TFMC winding vs. coil current in test
Phases 1 and 2. The difference between the measured losses and the
calculated resistive losses are the AC losses caused by the current
ripple of about 40 W (see Section 6.1.3).
Fig. 4.14. Re-cooling after a safety discharge from rated currents.
flow rates were adjusted to rated values after the daily
high voltage and interlock tests at low currents, which
did not require a high mass flow rate.
An overview of the complete test Phase 2 is given in
Fig. 4.20. The cool down started August the 20th and
the warm up finished December the 19th, 2002 without
significant problems. The availability of the TOSKA
facility was larger than 98%.
4.4. 80 kA current leads performance
4.4.1. Design of the 80 kA current leads
For the test of the TFMC in TOSKA, two 80 kA
current leads were designed and manufactured based
on the design principles developed within the last 15
years [55], see Fig. 4.21.
A significant experience was acquired from the construction
and the performance tests of the 30 kA forcedflow-cooled
current leads used for the POLO model
coil experiment, the LCT coil 1.8 K test, the W 7-X
conductor tests in the STAR facility, and the W 7-X
DEMO coil test. The 80 kA current leads were designed
based on that experience and according to the design
principles worked out in the course of construction of
forced-flow-cooled current leads and testing of those
devices.