Drastic improvement of I/sub c/ of Nb/sub 3/Sn CIC conductor by prestraining at room temperature

The strain sensitivity of Nb/sub 3/Sn cable is well known. However the practical process to compensate for this effect when 316 LN is used for the jacket has never been considered. In this paper different proposals are analysed in order to prevent the 316 LN jacket contracting more than the Nb/sub 3/Sn cable. A first experiment performed in the FBI test facility of KfK has shown that a prestrain of 0.3% carried out at 275 K on a short straight sample of cable in conduit conductor (3/spl times/3/spl times/4 Nb/sub 3/Sn strands of 0.73 mm in a 316 L conduit) produced an improvement of the critical current. The improvement in this condition is about 80%. Different designs of tooling usable for the CS and TF coils of ITER are described.