Flow rate measurement across the upper core structure of a sodium fast reactor using a scaled model and a simulant fluid

• Published in: Nuclear engineering and design Vol. 427; p. 113518
• Main Authors: Guenadou, D., Aubert, P., Descamps, J.P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2024
• Subjects: Code validation; Experiment; Mock-up; Sodium fast reactor; Mock-up; Sodium fast reactor; Code validation; Experiment
• ISSN: 0029-5493
• DOI: 10.1016/j.nucengdes.2024.113518

•A part of the flow coming from the fuel assemblies cross the Upper Core Structure (UCS).•Pressure loss versus flow rate in the guide tubes was determined in a mimic UCS.•The flow rate is calculated in the actual USC by measuring the height of water in the guide tubes.•The results are in the same order as those determined using the velocity integration method.•The errors due to the sensors are high but may be improved by a better calibration. In the purpose of the design of SFR reactors, the CEA is developing codes, which must be validated from experimental data. Since experiments with sodium are complicated, a part of the studies is performed on small scale mock-ups using water thanks to the dimensional analysis. The mock-up MICAS, representative of the ASTRID upper plenum at a scale 1/6th, allows studies of the thermal hydraulics behavior in the vessel for the code validation. Numerical codes usually model the Upper Core Structure (UCS) as porous media because of its complexity. This methodology requires data about the pressure loss coefficients of the different components of the UCS. They are evaluated using correlations from the literature, but this method leads to uncertainties owing the complex geometry of the UCS. One aim of the work carried out on the MICAS mock-up was to obtain data about the flow rate crossing the UCS to compare them with the numerical results. In former studies, it has been calculated by measuring and integrating the velocity around the core and the UCS. Another technic, based on pressure losses measurements, was performed in the aim of comparison. The pressure drop coefficients were calculated in a dedicated mock-up replicating the UCS geometry. These results and the measurements of the pressure losses in the MICAS UCS allowed determining the flow rate crossing this component. Comparisons with numerical and former method results show some discrepancies.