Study on sorption of radioactive nuclides by carbonates. Present and future researches

Studies on sorption/adsorption behavior of radioactive nuclides by carbonates in the environment including the experimental methods and the partition coefficients are reviewed, and the future necessary researches for the geological disposal of high level radioactive waste are shown. The ubiquitous carbonates are expected to sorb and retain the leached nuclides. The partition coefficient is an important value for the sorption - inclusion process of element into the carbonate crystal. It is calculated by two ways; empirically and thermodynamically, however, they are quite different. As the former depends on the physicochemical parameters such as precipitation rate and temperature, etc., the relationships between the empirical partition coefficient and the physicochemical parameters should be clarified. Furthermore, the data for fission product elements and actinides should also be collected systematically because they are insufficiently reported. (author)