Report of Magnetic Fusion Energy Group
The group’s discussion was principally concerned with the relatively near-term problems of the next generation of large fusion devices, which are expected to be constructed within 10–15 years. In this regard, it was generally felt that the major problems will be of a mechanical nature and that these will limit the maximum fields to ∿10–12 T. For such magnets, the critical current densities, fields and temperatures now being achieved in the best composites presently available, were felt to be quite adequate. Mechanical properties were thought to be much less satisfactory, however, and the group would welcome further improvements in strain tolerance. As a typical example, requirements for the conductor in the proposed ETF Tokamak might be a manufacturing strain of 0.8% and a cyclic operating strain of 0.2%. It may thus be seen that improved handling capability during coil manufacture is the major requirement. This could be brought about either by further improvements in materials properties or by better technologies for conductor fabrication or coil winding.