An analytical thermal model for the optimization of EU DEMO feeder thermal shields

The present work aims at defining a first design of the DEMO EU's feeder thermal shield for the CFT, by exploring the temperature distribution resulting from radiation and conduction coming from different sources including the vacuum duct, the containment duct and the cryogenic He lines on the thermal shield. In order to achieve these results, at first a numerical FEM representation was produced and parameterized. To ease the burden of such a complex and highly non-linear solution, an analytical model however was created and validated against the numerical one with very good results. The sensitivity of several parameters was computed with respect to the temperature distribution of the thermal shield and the heat flow to the containment duct, finding a candidate configuration for the thermal shield. To complete the study, an evolutive optimization based on gradient descent was implemented to understand the influence of the circumferential positioning of the cooling He lines.