Protection of conduction cooled Nb3SnSMES coil

A conduction tooled Nb3Sn SMES coil requires a protection analysis differen t from that of the Liquid helium cooled NbTi magnets. In a SMES coil constr ucted with a bronze processed Nb3Sn wire, hot spot temperature is high due to a slow normal zone propagation. In a conduction cooled system, re eddy c urrent generated heating in the cryogenic interface;enables a quench back. In order to design a proper protection scheme for a cryogen free Nb3Sn SMES system operating at 10 K, a computer code has been developed, The code sim ulates the quench behaviour of the coil protected with any combination of s hunt resistor, subdivision and quench bask, The modelling of the quench bac k requires the solution of the eddy current problem and the heat transfer b etween the coil and the interface, These are combined with the solution of the differential equations describing the protection with a shunt resistor or subdivision. Utilizing the developed code, the protection of a 0.2 MJ co nduction cooled Nb3Sn SMES coil has been designed.