An on-line radiochemical monitoring system was developed to provide control information for the pressurized cation exchange chromatography process used at Savannah River to recover kilogram quantities of transplutonium elements. The effluent from the ion exchange column is circulated past Nal, BF3, and Ge(Li) detectors located outside the primary shielding wall. The individual radioisotopes are qualitatively and quantitatively analyzed. The system uses a PDP-9 computer with direct memory access for the pulse-height analysis of incoming data.