[en] Electrochemical parametric pumping is a novel separation process in which cycles of reversible electrochemical processes on high surface area electrodes are conducted in synchronization with cycles of solution flow through the separating column. In the present work, isotope separation by electrochemical parametric pumping is studied theoretically. The proposed model is based on the similarity between the parametric pumping and the countercurrent processes and on the division of the separating column to cells when dispersion processes are neglected. Steady-state isotopic concentration gradients are calculated and process optimization is performed with respect to system parameters such as the fraction of the isotopes bound to the electrode, the solution displacement volume, and the fraction of the isotopes withdrawn as product. The model may also be applicable to other types of parametric pumping. 20 references, 13 figures