Preliminary thermo-structural analyses of the new DTT bolometric camera

Abstract

The Divertor Tokamak Test (DTT) facility is currently under construction at the ENEA Frascati Research Centre, Italy, with the aim of studying divertor configurations in support to the design and construction of ITER and DEMO. In the context of monitoring the radiated power, it is crucial to measure the entire spectrum of electromagnetic radiation emitted by the plasma. This need is particularly relevant in the divertor region, especially in the specific case of DTT scientific programme. This work presents the preliminary thermal and structural analyses of the bolometric camera foreseen to be implemented in the tomographic diagnostic system, aimed at monitoring the emissivity of the plasma total radiated power. First, the design has been optimised, minimising the space occupied in the port by the arrays of metal foil bolometers, still ensuring the best possible coverage of the lines of sight (LoS) in the vessel and at the same time avoiding interferences with other devices. Then, the devised layout has been validated with thermo-mechanical simulations, focusing on the design of the active cooling system of the bolometers themselves, necessary to manage the thermal conditions of the wall, particularly baking, and the intense loads during machine operations. The results confirmed that, under the specific conditions of mirror polishing of components, the currently proposed layout is promising, but needs further optimisation.