Experience highlights from the design and manufacture of U.S. LCT coils

The international Large Coil Task (LCT) is a major activity in the development of superconducting toroidal field (TF) coils for tokamak fusion reactors. The technical objective of this program is to design, build, and test six large TF coils, thereby producing information and data that can be used directly by program planners and designers of tokamak reactors. After an intensive competetive bidding cycle, contracts were awarded in 1977 to three U.S. industrial firms for the design and manufacture of test coils. Subsequently Japan, EURATOM, and Switzerland agreed to supply one coil each. External dimensions and minimum performance requirements are identical but freedom was allowed in the choice of internal design and manufacturing techniques. All six coils will be tested in a compact toroidal array in the Large Coil Test Facility (LCTF) in Oak Ridge, Tennessee. With the coil fabrication phase approaching completion, it is an appropriate time to review the major technical challenges and lessons from the design and manufacture of the three U.S. LCT coils.