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Development of CORC® cable terminations and
low-loss joints for use in magnets for fusion
Tapering of tapes allows even current injection
CORC® conductors
Future work
Joints tested with and without tapering
Consistent contact resistance between terminations and every tape in
an HTS cable is essential to energize the cable to its full capacity
Milled MSR
powder
Demountable joints
This work was in part supported by the US
Department of Energy under agreement
numbers DE-SC0013723, DE-SC0018125,
DE-SC0014009
Conductor on Round Core (CORC®) cables
and wires consist of High Temperature
Superconducting (HTS) tapes wound
helically around a small former
CORC® magnet cables and wires are being
developed for fusion magnets with high in-field
operating currents
Jeremy Weiss and Danko van der Laan Advanced Conductor Technologies LLC, Boulder, Colorado 80301, U.S.A
CORC® tube terminals can easily be
clamped together into joints
CORC® cables or wires can be bundled
together into cable-in-conduit
conductors (CICC) rated for currents of
50-100 kA or more
CORC®
magnet cables CORC®
magnet wires
Diameter 5 to 8 mm 2.5 to 4.5 mm
Temperature, Field 4.2 K, 20 T 30 K, 8 T 4.2 K, 20 T 30 K, 8 T
Current > 10,000 A > 7,500 A > 5,000 A > 3,500 A
Current density Up to 600
A/mm2
Up to 450 A/mm2
Up to 450 A/mm2
Up to 340 A/mm2
Tim Mulder and Herman ten Kate CERN and University of Twente
Tube terminals: R (76 K) = 5 to 50 nΩ
0 1000 2000 3000 4000
0.0000
0.0005
0.0010
0.0015
0.0020
0.0025
0.0030
101 n184 n
R (at 70 % Ic)
Untapered
Single taper
Fully tapered
V(V
)I(A)
76 K
350 n
Top terminals
(lap joint with current lead)
Bottom terminals/joint
(praying hands joint)
Plug style Male to Female connectors:
R (76 K) = 465 nΩ (old data, not-tapered)
Clamped praying hands joint between tube
terminals: R (4.2 K) = 7.9 nΩ
Image courtesy
of X. Wang
Uneven current injection from terminals with untapered tapes results in higher overall
contact resistance and non-linear V(I) transitions below the critical current
Joints tested between two CORC®
cables with 30 tapes each
Thu-Mo-Po4.04-02 [25]
0 5000 10000
0.00
0.05
0.10
77K
194 n
Vo
lta
ge
(m
V)
I(A)
7.9 n
4.2K
6x1 CORC® CICC terminations and joints
CORC® bundle O.D. 22 – 24 mm
Tim Mulder’s thesis: Advancing ReBCO-CORC Wire and Cable-
In-Conduit Conductor Technology for Superconducting Magnets
https://doi.org/10.3990/1.9789036546164
6x1 CICC terminations: R (5 K) = 2 to 4 nΩ
Splice between two samples: R (5 K) = 3.3 nΩ
Two samples tested in series at
the SULTAN test facility
Terminal dimensions
Sample 1: Top terminal
Sample 1: Bottom terminal
Sample 2: Top terminal
Sample 2: Bottom terminal
Sample 1: Total
Sample 2: Total
Plug style joint with tapered cables
Plate style joints
Next generation of CORC® demountable
joints aiming at < 1 nΩ resistance at 4.2 K
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