Alteration-Phase formation and Associated Cesium Release During Alteration of R7T7 Waste Glass

Abstract

ABSTRACTStatic corrosion tests were performed with an inactive HLW glass of R7T7 type in order to evaluate alteration-phase formation and associated Cs release during the glass corrosion. The tests were performed in NaOH solutions at elevated temperatures in order to accelerate the corrosion. Crystalline phases formed in the corroded glass were analyzed by use of XRD, in addition to the solution analysis. The results indicated that; 1)Analcime or Na-beidellite or both of them form during the corrosion depending on the conditions, 2)Si rich amorphous phases are contained in the alteration-phases, 3)In addition to solution pH, solution concentrations of Na and K sensitively affect formation of analcime and Na-beidellite, 4)Analcime formation accelerates the glass corrosion, 5)Most of Cs in the glass is retained in the alteration-phases by sorption onto Na-beidellite or incorporation into amorphous phases and pollucite