The DTT device: Rationale for the choice of the parameters

The main goal of the Divertor Tokamak Test facility (DTT) is to explore alternative power exhaust solutions for the next step after ITER, i.e., a demonstration power plant DEMO that will explore steady-state operation. The principal objective of DTT is to mitigate the risk of a difficult extrapolation to fusion reactor of the conventional divertor based on detached conditions under test on ITER. The task includes several issues, but with the main target to study the completely integrated (physics-technology and bulk-edge) power exhaust problems and to demonstrate how the possible implemented solutions (e.g., advanced divertor configurations or liquid metals) can be integrated in a DEMO device. This paper shows how the parameters for the design of a “flexible” facility, capable to perform this difficult task, can be worked out within the constraint of a fixed budget.