XAFS analysis of ruthenium in simulated iron phosphate radioactive waste glass

Abstract The chemical state of ruthenium in simulated iron phosphate radioactive waste glass was investigated by conventional X-ray absorption fine structure (XAFS) and imaging XAFS analyses. The EXAFS analysis suggested that ruthenium was contained as glass phase when content of the waste components was less than 10 wt.% in 30 mol%Fe2O3-P2O5 base glass. In other samples, crystalline RuO2 was observed and became prominent with the increase of waste content. According to the imaging XAFS analysis, RuO2 particles in all samples had length smaller than 50 μm. Large size aggregations of RuO2, which are found frequently in nuclear waste borosilicate glass, were not seen in any of the iron phosphate glass samples.