On the evaluation of the DEMO WCLL breeding blanket sector thermal-hydraulic performances at a system level

To obtain an affordable BB design, one of the key issues is assessing its thermal-hydraulic performances during operational and accidental conditions. For this, an analysis of the component transient behavior is needed to improve and refine the project. To achieve this goal, during the last year, the Nuclear Engineering Research Group of Sapienza University of Rome, in collaboration with ENEA, has developed a detailed model of the DEMO WCLL BB sector, including both the inboard and outboard segments. The rationale has been dividing the overall stack of cells belonging to each segment in poloidal sections. The number of these sections has been the object of a sensitivity study. The preliminary objective of this work is to have a dedicated BB sector model to evaluate its thermal-hydraulic performances at a system level during the DEMO normal operations, considering the pulsed plasma regime and the spatial distributions of the various loads insisting on this component. In addition, the developed input deck allowed to have insights into the BB behavior during accidental conditions, demonstrating the capability of the current design to effectively withstand such scenarios without exceeding safety margins. The level of detail adopted to prepare the BB model enabled to preliminary exclude the occurrence of local damaging phenomena, such as thermal crisis.