Abstract
For the design of radwaste disposal repository, the measurement of radioactivity in it is very important. Long half-life nuclides such as Tc-99 (t1/2=2.13x105y) which is very soluble and I-129 (t1/2=1.6x107y) which is easy to volatile play important roles for the environment and human. In general, the radioactivity is obtained from the energy of radiation emitted from the nuclides or from the “Scaling factor” method developed by Electric Power Research Institute (EPRI) of America. However, both of the methods are difficult to measure the radioactivity for long half-life nuclides. In this study, alkaline digestion used as the method of sample pretreatment for iodine and the TEVA extraction chromatographic resin for technetium are combined with ICP-MS to overcome these difficulties. The overall sample pre-treatment steps of both iodine and technetium have good precision and accuracy and the method detection limits of iodine and technetium by ICP-MS are 3 ng/L and 0.02 ng/L that are extremely lower than that by the traditional liquid scintillation counter (10 ng/L for 99Tc and 700 ng/L for 129I). The radioactivity of the real samples obtained by this method are all greatly lower than that obtained by the scaling factor. It proves that this method can improve the disadvantages of traditional methods.