Fast and strongly exothermic reactions can exhibit a well-known phenomenon called "thermal runaway". To identify high productivity and safe conditions for these reactions, with particular reference to industrial semibatch processes carried out using both isothermal and isoperibolic temperature control mode, a dedicated classification/optimization software has been implemented. This software is able to both classify a set of operating parameters from the thermal stability viewpoint and identify the optimum reacting/synthesis conditions using a topological criterion that binds the so-called "QFS region", where reactants accumulation is low and all the heat released is readily removed by the cooling equipment. During the search for system optimum a number of safety and quality constraints can be taken into account. The software reliability, in terms of both classification and optimization ability, has been tested using both laboratory and industrial scale experimental data. Obtained results confirm a good agreement between theoretical predictions and experimental evidence. (C) 2013 Elsevier Ltd. All rights reserved.