Inside the research field of Nuclear Fusion, the Divertor Tokamak Test facility (DTT) [1] is an Italian project, aimed at investigating alternative power exhaust solutions under integrated physics and technical conditions that can reliably be extrapolated to the future nuclear fusion DEMOnstration power plant. In DTT, to achieve a large ratio value of the power crosses the separatrix, it is necessary to provide to the plasma supplementary heating power of 45 MW. One of the three heating systems is the Electron Cyclotron Resonance Heating. Its architecture is based on 4 clusters, each one constituted of 8 gyrotrons (Radio-Frequency source), 1 quasi-optical multi-beam transmission line (MBTL) and 8 independent antennae. The power, generated by the RF sources (170 GHz, 1 MW, 100 s pulse duration), is transmitted by a series of oversized flat and focusing mirrors and launched into the plasma by an antenna. In the MBTL, the reflection of the 8 separate microwave beams on the same mirror surface heats the structure, being a fraction of beam power absorbed. So, during the RF operation, the mirror temperature increases, thus generating deformations due to thermal expansion that would result in lower transmission line efficiency. For this reason, the mirrors need to be cooled and carefully designed in terms of thermal and structural properties, to guarantee the required optical performances. The refrigerant fluid is the water and the maximum power to be disposed of is 13 kW with heat flux peaks in the range of 0.1-0.2 MW/m2. In this work the conceptual design of different MBTL flat and parabolic mirrors and their cooling layouts is presented, resorting to thermo-structural finite element simulations. The presented analyses aim to individuate the deformed structures and reconstruct the deformed reflective surfaces necessary to include this effect in the evaluation of the transmission line losses.
Thermal and structural analyses on different mirrors of the Multi Beam Transmission Line of DTT ECRH system
Bruschi A;Garavaglia S;Granucci G;Moro A;Platania P;
2023
Abstract
Inside the research field of Nuclear Fusion, the Divertor Tokamak Test facility (DTT) [1] is an Italian project, aimed at investigating alternative power exhaust solutions under integrated physics and technical conditions that can reliably be extrapolated to the future nuclear fusion DEMOnstration power plant. In DTT, to achieve a large ratio value of the power crosses the separatrix, it is necessary to provide to the plasma supplementary heating power of 45 MW. One of the three heating systems is the Electron Cyclotron Resonance Heating. Its architecture is based on 4 clusters, each one constituted of 8 gyrotrons (Radio-Frequency source), 1 quasi-optical multi-beam transmission line (MBTL) and 8 independent antennae. The power, generated by the RF sources (170 GHz, 1 MW, 100 s pulse duration), is transmitted by a series of oversized flat and focusing mirrors and launched into the plasma by an antenna. In the MBTL, the reflection of the 8 separate microwave beams on the same mirror surface heats the structure, being a fraction of beam power absorbed. So, during the RF operation, the mirror temperature increases, thus generating deformations due to thermal expansion that would result in lower transmission line efficiency. For this reason, the mirrors need to be cooled and carefully designed in terms of thermal and structural properties, to guarantee the required optical performances. The refrigerant fluid is the water and the maximum power to be disposed of is 13 kW with heat flux peaks in the range of 0.1-0.2 MW/m2. In this work the conceptual design of different MBTL flat and parabolic mirrors and their cooling layouts is presented, resorting to thermo-structural finite element simulations. The presented analyses aim to individuate the deformed structures and reconstruct the deformed reflective surfaces necessary to include this effect in the evaluation of the transmission line losses.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
