Control of nuclear reaction interferences in environmental analysis of I-129 using neutron activation

Neutron activation analysis for 129 I at levels close to the detection limit requires special consideration of nuclear reaction interferences. These interferences can be caused bu U, Cs and Te impurities, constituent of the materials to be irradiated, or by the chemical interferences present in the reagents used in the pre-irradiation purification. This work analyses the development and the integration of several steps applied to control and/or to eliminate potential sources of error in the determination of 129 I, as well as to present spurious results and thus to achieve the minimum detection limit. The pre and post-irradiation purification, neutron irradiation, radioactive counting and data analysis steps were analysed. High-resolution gamma spectrometry was used for detection and measurement of low levels of interferences. The magnitude of the nuclear and chemical interferences that affect this procedure has been determined. (author)