Design of the First Divertor in the DTT Facility

The Divertor Tokamak Test facility (DTT) under construction in Italy aims at studying the power exhaust for the future nuclear fusion power plants. The tokamak is, in fact, designed to have conditions at the divertor comparable to those in ITER and DEMO. DTT will work alongside ITER, allowing with its flexibility important support for the DEMO design. DTT divertor design and construction has been included in the activities 2021-2027 of the EUROfusion consortium and is conducted within the work package DIV. Focusing on the divertor study, it is planned that DTT divertor will be changed several times during the machine life. Accordingly, huge efforts and resources are devoted to the divertor remote handling. In the first phase of operation, DTT will focus on the study of the most promising plasma scenarios for DEMO. For this reason, the first divertor was designed to accommodate different magnetic configurations. With this aim, the largest flexibility was ensured by allocating to the divertor the widest possible space, and using the design and technologies that ensure the highest performance in power removal capacity. For the dome, the same monoblock design of the inner and outer vertical targets was used giving to the dome the characteristics of a third target and providing the required flexibility in the plasma scenarios testing. The technology chosen for the plasma facing unit manufacturing is the one developed in the ENEA laboratory and qualified for the production of the ITER inner vertical divertor target. Starting from the preliminary requirements, this paper presents the compatibility of the various magnetic configurations with the constraints posed by the integration and the technological choices. The comparison between configurations in terms of power exhaust (performed with the 2D edge fluid-kinetic SOLEDGE2D-EIRENE code), the main results of the structural, hydraulic and pumping verification are reported.