Selection of ⁹⁰Sr distribution coefficient in environmental impact assessment of low and intermediate radioactive disposal sites

Distribution coefficient is a key parameter which is used to characterize the migration of radionuclides in soil media around the disposal site, and has a significant impact on the results of environmental impact assessment. There are great differences for different measurement methods, such as experimental period, economic cost and accuracy. From the engineering point of view, the method with short experimental period and low cost should be chosen as the priority, in the premise that the measurement result doesn't vary much. ⁹⁰Sr is one of the typical radionuclides in low and intermediate level radioactive solid waste which should be disposed in near surface. Batch and column experiments are conducted to obtain the migration rules of ⁹⁰Sr in several soils including sandy soil, clay, and loess, in vadose zone in arid area of Northern China. And the difference of ⁹⁰Sr distribution coefficient measured by different test methods is analysed. The results show that the dynamic column experiment method should be preferred for the measurement of ⁹⁰Sr distribution coefficient for the sandy soil, and the batch experiment method can be used for loess and clay, in terms of environmental impact assessment of low and intermediate level disposal sites. (authors)