Comparative analysis of different approaches for theoretical simulation of ultracentrifuges isotopic separation cascades

In order to simulate a real cascade performance in terms of the external and internal flowrates and isotopic compositions, it is necessary to solve a system of equations composed of the internal mass balances for the element (U) and for the desired isotopes. Considering the separation of a binary isotopic mixture, for a cascade with n stages, we have a system of 4 n independent equations with 6 n unknowns. This kind of system has infinite solutions, unless we introduce practical or theoretical new equations describing the centrifuge separation performance and/or use approximations in terms of restrictions to the stages behaviour. Depending on the equations and/or restrictions we use, the simulations results can be quite different. In this paper, six different combinations between theoretical equations and stage restrictions will be analyzed and compared using experimental results, in order to establish the best mathematical model to be used in the theoretical simulation of a real cascade performance.. (author)