For achieving high separation efficiency and a large throughput in the nuclear fuel reprocessing industry, it is crucial to have a profound understanding of the flooding characteristics in pulsed disc and doughnut extraction columns (PDDCs). For this purpose, the least absolute shrinkage and selection operator (LASSO) method was utilized to obtain predictive equations that provide high applicability and analytical convenience. The effects of three operating conditions (dispersed-phase velocity, continuous-phase velocity, and pulse intensity) on the hydrodynamic parameters (dispersed phase holdup, slip velocity, characteristic velocity, and flooding point) were studied in a Φ50 PDDC in the kerosene-water system.

The LASSO method was applied to select highly correlated features of the hydrodynamic parameters and to propose second-order prediction equations. The effectiveness of LASSO was also compared to the published correlations and traditional linear regression. The second-order-regression of LASSO produced more intuitive prediction equations with the mean relative error within 15%. The impact of each operating variable on the hydrodynamic parameters was quantitatively analyzed by calculating the partial derivatives of these prediction equations. The dispersed-phase flow rate predominantly affects the holdup within the operating conditions. Pulse intensity emerges as the primary factor affecting slip velocity, characteristic velocity, and flooding throughput.