Development of a selective scintillation resin for the analysis of radioactive tin

Abstract

Nuclear wastes content high quantity of radioactive isotopes including isotopes of tin. These radioactive isotopes of tin have a relatively low yield as a fission product but they will have got an important relevance in the future due to their high mobility and the long-life time of some of them, as 126Sn and 121mSn. These isotopes are usually determined by liquid scintillation technique which leads to do several steps and to use high amounts of reagents in the purification and pre-concentration processes of radionuclides. Cross-linked plastic scintillation resins are a new material employed to separate, pre-concentrate and measure radionuclides in only one step as well as to obtain less contaminant wastes than those generated by liquid scintillation technique. The objective of this study is the development of C-PSresin used to pre-concentrate and measure the β-emitter isotopes of tin. First, the composition of resin which allows the best working conditions is determined and that corresponds to 80% of TBP in n-dodecane. Then, the elution medium effect in selectivity of C-PSresin is evaluated using cesium and antimony as interfering metals. From this study, it is determined the optimal elution medium that is HCl 2 M because it causes a quantitative retention of tin and a complete elution of cesium and antimony. Finally, the extraction and measurement of a radioactive sample from nuclear wastes is done. Because of the inexistency of a standard of radioactive tin, it is calibrated the detection efficiency depending on radionuclide energy using radioactive standards of known activity and energy. Thanks to this calibration, activity of the radioactive sample is determined with an error close to 3%