Structural integrity evaluation of the DTT plasma facing unit using detailed CFD and thermo-mechanical analyses

A new Divertor Tokamak Test (DTT) facility is currently being built in Italy to investigate different divertor configurations under different plasma scenarios. The divertor and in particular its target, consisting of Plasma Facing Units (PFUs), is exposed to high heat loads due to plasma fluence. In this paper, the structural integrity of the PFU is evaluated for a reference Single Null (SN) divertor configuration under three different plasma scenarios. A comprehensive structural integrity analysis has been carried out in three stages. In the first stage, computational fluid dynamic (CFD) analyses of the divertor’s PFU with a cooling channel were performed at three different heat loads corresponding to three plasma scenarios. The temperature fields calculated by the CFD analyses were then used as input for the second stage, in which thermo-mechanical simulations were performed to predict the stresses and displacements in the PFU. Due to the high local heat loads, high stresses or even yielding are expected in the PFU’s structural components. Therefore, in the third stage, the structural integrity of critical cross-sections has been verified using the Structural Design Criteria for In-vessel Components (SDC-IC). It has been demonstrated that structural components of the PFU are able to withstand the expected loads, although some non-structural components experienced yielding while not exceeding the critical values.