[en] This study was made to update an existing report on the current and future uses of ion exchange as a method for treating liquid radioactive waste streams at light-water reactor (LWR) power plants. Data were obtained from questionnaires sent to nuclear power plants, architect-engineering firms, and equipment suppliers. These data were supplemented by personal communications and, in a few cases, by information extracted from company reports. Detailed results obtained from responses received from the operators at 14 boiling water reactors (BWRs) and 19 pressurized water reactors (PWRs) are tabulated in the Appendix. Summary tables are presented for average decontamination factors (DFs) and for volumes and activities of the spent resin generated by operating reactors. A list of recommendations for improving the efficiency of the ion exchange process is also included