THE SUPERCONDUCTING TOROIDAL FIELD-COILS AND THE CENTRAL SOLENOID OF ITER - CONCEPT EVOLUTION AND PRESENT STATUS

During the NET Conceptual Design Phase, the design of the superconducting coils for the toroidal system and the central solenoid changed considerably in terms of conductor layout, jacket thickness, mechanical structure, number of coils, etc. Only one concept survived the continuous changes: all the coils were to be built with the pancake technique. This concept was inherited by ITER, but in 1992 the layer-by-layer technique was strongly proposed with the intent of solving or simplifying a number of problems, the most important of which the transmission of forces. The advantages and disadvantages of the two techniques are being analysed by associated laboratories and industries. The most recent results of these studies and those of other construction proposals are described.