Search of the optimum design used in practical squared-off cascades is usually started with optimization of various model cascades with the specified concentrations of a target component in their outgoing flows. After that, the approximation of the found model cascade is carried out. These two stages of research have been executed in solution of the problem of manufacturing the isotopically modified molybdenum (IMM), which is considered as an alternative construction material for nuclear power plants. A quasi-ideal cascade is chosen as a model cascade. Based on the results obtained for model cascades, the performance of single-cascade and double-cascade schemes has been analyzed under various requirements for thermal neutron capture cross section of the produced isotope product, and design of the squared-off cascades is completed. It is demonstrated that the most efficient separation scheme could be realized by means of either a single-cascade or double-cascade scheme, depending on the specific requirement. The 4-section squared-off cascades provide the highest metrics for cascade efficiency. The results of this research could provide necessary guidance for further design and construction of a separation plant for large-scale production of IMM. (C) 2017 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.