A physical-mathematical model of jet mixing was developed based on the multicomponent flow model, k-ε turbulent pulsation model and implicit pump model. Verification of the model was based on experimental data. It was found that the modeling error is less than 12 %. Mathematical modeling of mixing processes in extraction cycle nitric acid uranium solutions reception tanks was performed using the developed physical-mathematical model. The analysis results showed that there is a stagnation zone in the tank. The location and the size of the zone and its impact on mixing process were determined. Some ways of mixing efficiency improvement are offered.