Journal of Nuclear Fuel Cycle and Waste Technology

Radiotracer experiments were performed over two years using pot cultures in a greenhouse to investigate soil-to-rice seeds transfer factors of radioiodine and technetium for paddy fields around the radioactive-waste disposal site in Gyeongju. Before transplanting rice seedlings, the top about 20 cm soils were thoroughly mixed with 125I (2007) and 99Tc (2008), and the pots were irrigated to simulate flooded rice fields. Transfer factors were determined as the ratios of the radionuclide concentrations in dry rice seeds (brown rice) to those in dry soils. Transfer factors of radioiodine and technetium were in the ranges of 1.1×10-3～6.4×10-3 (three soils) and 5.4×10-4～2.5×10-3 (four soils), respectively, for different soils. It seems that the differences in the clay content among soils played a more important role for such variations than those in the organic matter content and pH. As the representative values of radioiodine and technetium transfer factors for rice seeds, 2.9×10-3 and 1.1×10-3, respectively, were proposed. In order to obtain more highly representative values in the future, investigations for the sites of interest need to be carried out continuously.

Keywords

Gyungju,Paddy Soil,Rice Seeds,Transfer Factor,Radioiodine,Technetium