Engineering challenges in the tokamak program

The challenge posed by tokamak is discussed in the context of the Engineering Test Facility, noting the complexity, scale, and uncertainty of the undertaking. With regard to uncertainty, it is noted that there are unresolved physics issues relating to confinement, heating, and control. With regard to scale, it is pointed out that challenges are being met for both conventional and superconducting coils. Considerations of scale are such that favor will be given to those construction techniques that are most amenable to pre-construction of components and simplified field assembly. Complexity arises from the fact that the requirements imposed on fusion systems are sometimes conflicting. In addition, the components of a system may be highly interrelated or else located in inaccessible places. The importance to the U.S. of the experience with fusion systems gained in other countries is stressed