The DTT device: Power and particle exhaust

The possible scenarios at full power of the DTT (Divertor Test Tokamak) device with the standard single null (SN) and X divertor (XD) configurations have been analysed for the aspect of safely handling the power to be exhausted on the divertor targets. In this conceptual design phase the computational tools have been chosen mainly on the basis of their simplicity and rapidity. The code COREDIV was used for a preliminary self-consistent description of the coupled edge-core system. Subsequently, a more punctual analysis has been carried out on the SOL with the TECXY code. COREDIV results show that operations without impurity seeding may be problematic in all scenarios, and especially at the higher densities where tungsten is virtually absent in the core and the core radiation very low. The main outcome of this study is that in term of global parameters little difference exists between the two configurations for low working densities. The reason is identified in the fact that the topology modifications occur in region where the dissipative processes, radiation inelastic collisions etc.. are rather negligible to be enhanced at significant level. The situation shows different at higher density where the XD seems indeed to favour detached operations and strongly radiating regimes. This trend is reinforced by lowering the power entering the SOL and by faster cross-field diffusion. These very important regimes seem to be reachable by the advanced configurations of DTT, for some appropriate choice of the working parameters. (C) 2017 Published by Elsevier B.V.