The installation of the JET pumped divertor systems inside the vacuum vessel

The JET (Joint European Torus) pumped divertor, designed to study impurity control, will be installed during 1992/1993. The related in-vessel components are essentially four magnetic coils, 48 beryllium divertor plate assemblies, one toroidal LHe cryopump, eight ICRH (ion cyclotron resonance heating) antennae, and poloidal limiters. With the exception of the magnetic coils, which will be wound and brazed inside the vessel, all other components will be preassembled and prepared before installation. To minimize the installation time and to optimize the working conditions inside the vessel (beryllium, tritium, radiation limited space) suitable procedures, jigs, and equipment have been developed and special working methods and organization will be implemented. The authors describe the organization and the installation principles to undertake and to accomplish all the activities. The work sequence to integrate the installation of the various components is presented, and the reference system with respect to the magnetic configuration and the achievable accuracy is discussed