Thermal-hydraulic Performance of Water-Cooled Ceramic Breeder Test Blanket Module

Abstract

A comprehensive thermal–hydraulic evaluation of the Water‑Cooled Ceramic Breeder (WCCB) Test Blanket Module (TBM) to be tested in ITER was conducted using a combined approach of Computational Fluid Dynamics (CFD) analyses, finite‑element thermal analyses, and full‑scale experiments. The CFD results showed that most regions of the First Wall (FW) attain coolant velocities above 1 m/s, supporting the validity of previously assumed heat‑transfer coefficients. Localized low‑velocity regions were identified near the partition plate and the outlets of the 3‑mm channels; however, conservative thermal analyses assuming zero heat‑transfer coefficient in these areas confirmed that FW temperatures remain below the F82H limit of 550 °C under both design (0.30 MW/m²) and maximum (0.84 MW/m²) ITER heat loads. Pressure‑drop analyses revealed a total submodule pressure drop of 57.2 kPa, with U‑shaped pipes contributing more than half of the total loss. Full‑scale pressure‑drop measurements, combined with a dedicated bypass loop to isolate inlet and outlet losses, showed good agreement with the CFD predictions for mass flow rates up to 0.1 kg/s. These results validate the numerical models and confirm that the current WCCB TBM submodule satisfies thermal–hydraulic requirements. The established methodology provides a foundation for future optimization and higher‑flow experimental campaigns.