Fabrication of the conductor for the Mirror Fusion Test Facility for Lawrence Livermore Laboratory

Large superconducting magnets are presently being designed for controlled thermonuclear fusion, energy storage and MHD applications. Mechanical, electrical and thermal requirements of these devices have led to the design of a new generation of conductors having a higher overall current density than the ''bubble chamber'' type conductors without sacrificing the necessary stability. A process to manufacture a monolithic conductor having internal cooling passages is described. The internal passages are formed by coining a pattern on a high-conductivity copper strip and forming this strip around a solder coated rectangular multifilament NbTi core. After forming, the assembly is heated and compressed to firmly solder the core to the coined strip. Perforations in the strip allow liquid helium to circulate along the internal passages thereby increasing the cooled perimeter of the conductor