Analysis of I-129 in radwastes by neutron activation

Determination of 129I activity of low-level waste has become important from the standpoint of radiation safety and environmental concern. The 129I generated from power plants could be released into the environment through the subsequent fuel reprocessing and waste disposal. In order to minimize this impact, the concentrations of 129I and some affiliated radionuclides in the wastes to be disposed of should be determined and put in compliance with the stipulated regulations. In this work, neutron activation analysis is proposed to determine 129I/127I and 129I in radwastes. The long-lived 126I, activated from 127I, is selected to replace 128I as an indicator of stable iodine. Long-term neutron irradiation and γ-ray counting are permitted and the related detection limit can be improved. In addition, the proposed method has related advantages of low-counting interferences and convenience for chemical operation over traditional methods; these make it a practical alternative for analyzing 129I in radwastes in a facility near a research reactor.