Age dating of liquid 90Sr-90Y sources

In the context of age dating of 90Sr, the selective adsorption of zirconium ions from the mixture with strontium and yttrium by adsorbents based on TiO2 with a chemically modified surface was investigated. The general features of the separation process of strontium, yttrium, and zirconium in batch conditions were determined. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to analyze the initial and residual concentrations of the studied cations. Separation of 90Zr and 90Sr from a liquid source containing 90Sr-90Y using adsorbents based on TiO2 was performed for the first time. The ratio of 90Zr/90Sr was measured, and the age of liquid 90Sr-90Y sources was determined. In addition, we studied the age dating of 90Sr-90Y sources using a combination of liquid-scintillation counting of 90Sr and ICP-MS measurement. The results of both methods - the method of age-dating with the chemical separation of isotopes and the combination of LSC and ICP-MS analysis - agree very well and thus serve for cross-validation. Moreover, the combination of the two methods increases the confidence in the age-dating results of 90Sr-90Y sources.

Investigation of the chemical and radiation stability of titanium dioxide with surface arsenate groups during 90Sr adsorption

The chemical and radiation stability of titanium dioxide with surface arsenate groups during ⁹⁰Sr adsorption has been studied. The oxalate technique has been used to obtain a solution containing ⁹⁰Sr from the objects of the aquatic environment of the Chornobyl Exclusion Zone. The dependence of the strontium adsorption on the acidity of the solution and the initial activity of the solution (Bq per mL) has been shown. SEM, XRF, and EDS spectroscopy confirm the chemical resistance of 4As-TiO₂ during regeneration. According to the study with ⁹⁰Sr, the decrease in the adsorption capacity of 4As-TiO₂ during regeneration is associated with incomplete leaching of strontium from 4As-TiO₂ micropores. Using an electron accelerator, the radiation resistance of titanium dioxide with surface arsenate groups to β^- -particles with an energy of 1 MeV has been studied. The invariability of the elemental composition and adsorption properties of 4As-TiO₂ at irradiation doses of 5·10⁷Sv testifies to the high radiation resistance of 4As-TiO₂. The result obtained indicates the promise of 4As-TiO₂ for improving radiochemical methods.