Passive spherical check valve is a key component in the passive residual heat removal system of an integral fast reactor (IFR), since it opens and closes automatically with the primary pump flow and its flow resistance controls the natural circulation capability of the decay heat removal path. Hydraulic tests using liquid sodium at the reactor operating temperature are expensive and hazardous, so a mock-up working medium is required. In this work, experiments were performed with water as the working medium in a constant-temperature loop at 85 °C. The pressure drops across the valve were measured for forward volumetric flow rates, with the spherical blocking element fixed on its seat. In the present work, attention is focused on the forward-flow condition of the valve. A three-dimensional numerical model of the valve was then established and validated against the measurements, and good agreement was obtained. The validated model was further applied to liquid sodium at 360 °C with constant properties; the loss coefficient K calibrated from the water simulation was used to predict the liquid-sodium pressure drops, and the predicted values agree with those of the liquid-sodium numerical simulation. For the forward-flow condition, the simulation results indicate that the dimensionless loss coefficient of the valve depends only weakly on the Reynolds number and remains nearly constant in the forced-circulation range, and that the pressure drop increases monotonically with increasing radius of the spherical blocking element. The pressure-drop characteristics obtained in this way provide a direct basis for the design and analysis of the passive spherical check valve (PSCV) in IFR.


 

passive check valve,integral fast reactor,pressure-drop,characteristics,numerical simulation,liquid sodium