R&D for modification of RFX-mod fusion toroidal complex

An upgrade of the RFX-mod experiment is presently under design, aimed at widening the explored operational scenarios both in RFP and Tokamak configuration. The proposed upgrade implies a major modification and reconfiguration of the internal components of the machine, such as the replacement of the whole first wall, the change of the support system of the magnetic stabilizing shell and the adaption of the present toroidal mechanical support structure to provide the function of vacuum vessel. After the conceptual study developed to identify the feasibility of the proposed modification, the engineering design is presently being completed and supported by R&D activities developed to sort out specific critical issues related in particular to: 1) electrical connection and insulation of in-vessel components, to guarantee their reliability during normal and off-normal operation; 2) implementation of poloidal and toroidal crossed joints of the new vacuum vessel, with a novel solution conceived to ensure suitable vacuum tightness and proper electrical resistance, to allow the penetration of electro-magnetic fields within the plasma chamber. The contribution will focus on the design choices, implemented on the base of results of experimental tests performed on mock-ups of the new components.