Computational Fluid Dynamics aimed nuclear reactor design
Abstract: The design of the cooling system of nuclear reactors is supported by thermal-hydraulic scaled experiments and numerical simulations. In this work, we show the process and the experience we have gained in more than ten years of aiding the thermal-hydraulic design with CFD and scaled experiments. MYRRHA (Multi-purpose Hybrid Research Reactor for High-tech Applications) is a flexible fast spectrum nuclear reactor concept cooled by lead-bismuth eutectic. As liquid metals are opaque and usually hot, their experimental characterization is limited, making CFD an invaluable tool to explore their flow and thermal characteristics, especially in turbulent conditions.
Academic research helps to understand the underlying physical processes of liquid metal flows and allows parametric studies and identification of general rules leading to better models for the industrial context. Scaled water facilities represent the same geometry, but due to transparency optical measurements are possible, leading to a detailed description of the flow field. However, the thermal similarity is not achievable between water and liquid metals, so scaled liquid metal experiments are necessary to ensure the full characterization of the thermal behavior of the system under design. All the experimental efforts finally linked together with CFD to supply all the information that cannot be measured, allow the assessment of the design changes before construction and describe accidental scenarios that one wishes not to study experimentally due to safety hazards.
