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

Abstract

Static 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

Resumption of Alteration at High Temperature and pH: Rates Measurements and Comparison with Initial Rates

“…Effect of sodium. pH is buffered by NaOH additions in this study and by KOH additions in the one of Gin and Mestre (2001) and sodium seems to slightly favor resumption of alteration compared to potassium , Inagaki et al, 2002, Inagaki et al, 2006, possibly because of the important "structure-forming" function of Na + during zeolite precipitation (Liu et al, 2014). Effect of pH stability.…”

Accelerated Leach Testing of GLASS (ALTGLASS): I. Informatics approach to high level waste glass gel formation and aging

“…Inagaki also demonstrated that solution pH and solution concentrations of Na and K were involved in the formation of analcime vs Na‐beidellite (a smectite clay). Other phases such as smectite clays that are rich in Fe 3+ compared to Al 3+ do not appear to accelerate glass corrosion .…”

Durable Glass for Thousands of Years

“…Two different glasses were studied, SM58 that contained 1. [126] demonstrated that solution pH and solution concentrations of Na and K were also involved in the formation of undesirable analcime versus Na-bedellite (a smectite clay). Other zeolites and smectite clays that are rich in Fe 3+ compared to Al 3+ do not appear to accelerate glass corrosion [110,127,128].…”