RADIOCHEMICAL ANALYSIS OF I-129 IN RADIOACTIVE-WASTE STREAMS

I-129 is the longest lived of the volatile radionuclides produced in t he nuclear fuel cycle. This radionuclide emits soft beta-particles, a weak gamma-ray and X-rays. Since the half-life of I-129 is 1.57 X 10(7 ) y, the evaluation of optimum waste management practices, for this ra dionuclide, has received special consideration. This work proposes an analytical method for I-129 in radioactive ion exchange resins and eva porator concentrates based on two methods. The first method consists i n direct measurement, without chemical separation, by low energy gamma -ray spectrometry. The achieved detection limit of I-129, With 60 h of counting time, is 0.2 Bq. The second method is based on a radiochemic al separation process consisting in two precipitation steps of the bet a-gamma emitters present in the samples and I-129 measurement by low e nergy gamma-rays spectrometry. The achieved detection limit of I-129, with 5 h of counting time, is 0.02 Bq, ten times lower than those achi eved with the direct measurement method.