The quest for high particle energies of modern super conducting lepton and
hadron storage rings assumes a strong minimisation of the non-magnetic
interconnection zones when compared to the total magnetic length of the main
quadrupoles and the dipoles. The ratio of non-magnetic to magnetic zones in
the LHC is close to 3%. Such a low percentage leads to a very compact
design of systems and sub-systems situated in the interconnections, like the
mechanical compensation system, composed of the bellows expansion joints,
that have to compensate for the thermal contraction of the magnets. Given
the complexity of the LHC interconnections, the requirements concerning
their reliability were considerably increased since the availability of the
collider for physics cannot be compromised. The failure modes taken into
account in the present analysis are grouped into 3 categories: material
failures, structural stability failures and fatigue failures. Optimisation
of stainless steel for cryogenic applications has been carried out. Also, a
concept of reliability oriented parametric optimisation of the LHC
interconnections is presented.