  The level of current non-uniformity in NbTi CICCs sections near the joints in
combination with the magnet field profile needs attention in view of proper
joint design. The strand Joule power and current distribution at quench under
DC conditions of two samples of ITER Poloidal Field Coil conductors, as tested
in the SULTAN facility and of the so called PFCI Model Coil Insert, have been
analyzed with the numerical cable model JackPot. The precise trajectories of
all individual strands, joint design, cabling configuration, spatial
distribution of the magnetic field, sample geometry and using experimentally
determined interstrand resistance distributions have been taken into account.
Although unable to predict the quench point due to the lack of a
thermal-hydraulic routine, the model allows to assess the instantaneous strand
power at quench and its local distribution in the cable, showing the hot spots,
once the quench conditions in terms of current and temperature are
experimentally known., The analysis points out the relation of the above
mentioned factors with the DC quench stability of both short samples and coils.
The possible small scale and local electrical-thermal interactions were ignored
in order to examine the relevance of such effects in the overall prediction of
the CICC performance The electromagnetic code shows an excellent quantitative
predictive potential for CICC transport properties, excluding any freedom for
matching the results. The influence of the local thermal effects in the
modeling is identified as being marginal and far less than the generally
accepted temperature margin for safe operation.
