Study of alpha-nuclides sorption on granite by autoradiographic method

Sorption of two alpha nuclides, 237Np and 239Pu, on granite was studied by the autoradiographic method using a solid state track detector (CR-39). The autoradiographs for the surface of rock thin sections of the Inada biotite-granite which were immersed for 48h in the groundwater containing both nuclides, showed that the alpha nuclides sorbed preferentially on biotite rather than on quartz and feldspar. Mechanism of the alpha nuclides sorption on granite was discussed based on the results of optical microscopic observations of the thin section, track density measurements and alpha-ray spectrometry. It was considered that the ion exchange seems to be a major mechanism of the sorption of these nuclides on the granite. (author)