The task of real time chemical composition control of radiochemical process streams is a great challenge to analytical chemistry due to very complex composition of the media and high radioactivity. Most of the analytical methods employed at the moment assume tedious and time-consuming steps of sampling, sample pretreatment and sophisticated analysis. In this study we have developed potentiometric multisensor system which is capable of fast and simple direct quantification of U and Th in real process streams of radiochemical plant with relative errors around 10%. This appears to be a reasonable precision sufficient for technological monitoring purposes and gives a good promise for the development of novel approach to radiochemical analytics.